Arduino: python cleanup

- Move code in arduinobuilder.py to their own modules:
  - __main__.py
  - builder.py
  - core_installer.py
  - file_operations.py
- New log.py module
- os.system -> subprocess.run
- Move --run-* args in the 'show' subcommand under the 'run' subcommand.
  This allows running multiple steps in the same invocation. For
  example, this will execute 3 steps:

  arduino_builder run \
                  --run-objcopy \
                  --run-postbuild \
                  --run-upload-command teensyloader

Change-Id: Ibe5493689f39aa6e6aaeecf5bc7065929111499d
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/19143
Reviewed-by: Wyatt Hepler <hepler@google.com>
Commit-Queue: Anthony DiGirolamo <tonymd@google.com>

9 files changed, 1161 insertions, 874 deletions

diff --git a/pw_arduino_build/arduino.gni b/pw_arduino_build/arduino.gni
index bf30cd458..c21463251 100644
--- a/pw_arduino_build/arduino.gni
+++ b/pw_arduino_build/arduino.gni
@@ -32,7 +32,7 @@ declare_args() {
 }
 
 arduino_builder_script =
-    get_path_info("py/pw_arduino_build/arduinobuilder.py", "abspath")
+    get_path_info("py/pw_arduino_build/__main__.py", "abspath")
 
 _arduino_core_path =
     rebase_path("../third_party/arduino/cores/$arduino_core_name")
@@ -46,12 +46,20 @@ arduino_global_args = [
   arduino_package_name,
   "--compiler-path-override",
   _compiler_path_override,
-  "show",
-  "--delimit-with-newlines",
+]
+
+arduino_board_args = [
   "--build-path",
   rebase_path(root_build_dir),
   "--board",
   arduino_board,
   "--menu-options",
 ]
-arduino_global_args += arduino_menu_options
+arduino_board_args += arduino_menu_options
+
+arduino_show_command_args = arduino_global_args + [
+                              "show",
+                              "--delimit-with-newlines",
+                            ] + arduino_board_args
+
+arduino_run_command_args = arduino_global_args + [ "run" ] + arduino_board_args
diff --git a/pw_arduino_build/py/pw_arduino_build/arduinobuilder_test.py b/pw_arduino_build/py/builder_test.py
index 60eb1441f..60eb1441f 100644
--- a/pw_arduino_build/py/pw_arduino_build/arduinobuilder_test.py
+++ b/pw_arduino_build/py/builder_test.py
diff --git a/pw_arduino_build/py/file_operations_test.py b/pw_arduino_build/py/file_operations_test.py
new file mode 100644
index 000000000..7306fbbba
--- /dev/null
+++ b/pw_arduino_build/py/file_operations_test.py
@@ -0,0 +1,103 @@
+# Copyright 2020 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+"""Tests for file_operations module."""
+
+import os
+import shutil
+import tempfile
+import unittest
+from pathlib import Path
+from parameterized import parameterized
+
+import pw_arduino_build.file_operations as file_operations
+
+
+def file_set():
+    return [
+        "app.ino",
+        "core/asm.S",
+        "core/asm.s",
+        "core/pwm/pulse.c",
+        "core/pwm/pulse.h",
+        "libraries/a.c",
+        "libraries/b.cpp",
+        "libraries/c.cc",
+        "libraries/c.h",
+    ]
+
+
+def create_files(root_dir, file_names):
+    for file_name in file_names:
+        folder_path = Path(root_dir) / Path(os.path.dirname(file_name))
+        folder_path.mkdir(parents=True, exist_ok=True)
+        file_path = Path(root_dir) / Path(file_name)
+        file_path.touch(exist_ok=True)
+
+
+class TestFileOperations(unittest.TestCase):
+    """Tests to ensure arduino core library source files can be found."""
+    def setUp(self):
+        self.test_dir = tempfile.mkdtemp()
+
+    def tearDown(self):
+        shutil.rmtree(self.test_dir)
+
+    @parameterized.expand([
+        (
+            "sources recursive", file_set(), ["**/*.ino", "**/*.h", "**/*.cpp"],
+            [
+                "app.ino",
+                "core/pwm/pulse.h",
+                "libraries/b.cpp",
+                "libraries/c.h",
+            ]
+        ),
+        (
+            "directories recursive", file_set(), ["**"],
+            [
+                "core",
+                "core/pwm",
+                "libraries",
+            ]
+        ),
+        (
+            "directories one level deep", file_set(), ["*"],
+            [
+                "core",
+                "libraries",
+            ]
+        ),
+        (
+            "items one level deep", file_set(), ["*"],
+            [
+                "app.ino",
+                "core",
+                "libraries",
+            ]
+        )
+    ]) # yapf: disable
+    def test_find_files(self, test_case, base_fileset, patterns,
+                        expected_results):
+        """Test find_files on source files and directories.
+        """
+        create_files(self.test_dir, base_fileset)
+        result = file_operations.find_files(self.test_dir,
+                                            patterns,
+                                            directories_only=("directories"
+                                                              in test_case))
+        self.assertSequenceEqual(expected_results, result)
+
+
+if __name__ == '__main__':
+    unittest.main()
diff --git a/pw_arduino_build/py/pw_arduino_build/__main__.py b/pw_arduino_build/py/pw_arduino_build/__main__.py
new file mode 100644
index 000000000..0bdbcf124
--- /dev/null
+++ b/pw_arduino_build/py/pw_arduino_build/__main__.py
@@ -0,0 +1,457 @@
+#!/usr/bin/env python3
+# Copyright 2020 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+"""Command line interface for arduino_builder."""
+
+import argparse
+import glob
+import logging
+import os
+import pprint
+import shlex
+import subprocess
+import sys
+from typing import List
+
+from pw_arduino_build import core_installer, log
+from pw_arduino_build.builder import ArduinoBuilder
+
+_LOG = logging.getLogger(__name__)
+
+_pretty_print = pprint.PrettyPrinter(indent=1, width=120).pprint
+_pretty_format = pprint.PrettyPrinter(indent=1, width=120).pformat
+
+
+def list_boards_command(unused_args, builder):
+    # list-boards subcommand
+    # (does not need a selected board or default menu options)
+
+    # TODO(tonymd): Print this sorted with auto-ljust columns
+    longest_name_length = 0
+    for board_name, board_dict in builder.board.items():
+        if len(board_name) > longest_name_length:
+            longest_name_length = len(board_name)
+    longest_name_length += 2
+
+    print("Board Name".ljust(longest_name_length), "Description")
+    for board_name, board_dict in builder.board.items():
+        print(board_name.ljust(longest_name_length), board_dict['name'])
+    sys.exit(0)
+
+
+def list_menu_options_command(args, builder):
+    # List all menu options for the selected board.
+    builder.select_board(args.board)
+
+    print("All Options")
+    all_options, all_column_widths = builder.get_menu_options()
+    separator = "-" * (all_column_widths[0] + all_column_widths[1] + 2)
+    print(separator)
+
+    for name, description in all_options:
+        print(name.ljust(all_column_widths[0] + 1), description)
+
+    print("\nDefault Options")
+    print(separator)
+
+    default_options, unused_column_widths = builder.get_default_menu_options()
+    for name, description in default_options:
+        print(name.ljust(all_column_widths[0] + 1), description)
+
+
+def show_command_print_string_list(args, string_list: List[str]):
+    join_token = " "
+    if args.delimit_with_newlines:
+        join_token = "\n"
+    print(join_token.join(string_list))
+
+
+def show_command_print_flag_string(args, flag_string):
+    if args.delimit_with_newlines:
+        flag_string_with_newlines = shlex.split(flag_string)
+        print("\n".join(flag_string_with_newlines))
+    else:
+        print(flag_string)
+
+
+def run_command_lines(args, command_lines: List[str]):
+    for command_line in command_lines:
+        if not args.quiet:
+            print(command_line)
+        # TODO(tonymd): Exit with sub command exit code.
+        command_line_args = shlex.split(command_line)
+        process = subprocess.run(command_line_args,
+                                 stdout=subprocess.PIPE,
+                                 stderr=subprocess.STDOUT)
+        if process.returncode != 0:
+            _LOG.error('Command failed with exit code %d.', process.returncode)
+            _LOG.error('Full command:')
+            _LOG.error('')
+            _LOG.error('  %s', command_line)
+            _LOG.error('')
+            _LOG.error('Process output:')
+            print(flush=True)
+            sys.stdout.buffer.write(process.stdout)
+            print(flush=True)
+            _LOG.error('')
+
+
+def run_command(args, builder):
+    """Run sub command function.
+
+    Runs Arduino recipes.
+    """
+
+    if args.run_prebuilds:
+        run_command_lines(args, builder.get_prebuild_steps())
+
+    if args.run_link:
+        line = builder.get_link_line()
+        archive_file_path = args.run_link[0]  # pylint: disable=unused-variable
+        object_files = args.run_link[1:]
+        line = line.replace("{object_files}", " ".join(object_files), 1)
+        run_command_lines(args, [line])
+
+    if args.run_objcopy:
+        run_command_lines(args, builder.get_objcopy_steps())
+
+    if args.run_postbuilds:
+        run_command_lines(args, builder.get_postbuild_steps())
+
+    if args.run_upload_command:
+        command = builder.get_upload_line(args.run_upload_command,
+                                          args.serial_port)
+        run_command_lines(args, [command])
+
+
+# pylint: disable=too-many-branches
+def show_command(args, builder):
+    """Show sub command function.
+
+    Prints compiler info and flags.
+    """
+    if args.cc_binary:
+        print(builder.get_cc_binary())
+
+    elif args.cxx_binary:
+        print(builder.get_cxx_binary())
+
+    elif args.objcopy_binary:
+        print(builder.get_objcopy_binary())
+
+    elif args.ar_binary:
+        print(builder.get_ar_binary())
+
+    elif args.size_binary:
+        print(builder.get_size_binary())
+
+    elif args.c_compile:
+        print(builder.get_c_compile_line())
+
+    elif args.cpp_compile:
+        print(builder.get_cpp_compile_line())
+
+    elif args.link:
+        print(builder.get_link_line())
+
+    elif args.objcopy:
+        print(builder.get_objcopy(args.objcopy))
+
+    elif args.objcopy_flags:
+        objcopy_flags = builder.get_objcopy_flags(args.objcopy_flags)
+        show_command_print_flag_string(args, objcopy_flags)
+
+    elif args.c_flags:
+        cflags = builder.get_c_flags()
+        show_command_print_flag_string(args, cflags)
+
+    elif args.s_flags:
+        sflags = builder.get_s_flags()
+        show_command_print_flag_string(args, sflags)
+
+    elif args.cpp_flags:
+        cppflags = builder.get_cpp_flags()
+        show_command_print_flag_string(args, cppflags)
+
+    elif args.ld_flags:
+        ldflags = builder.get_ld_flags()
+        show_command_print_flag_string(args, ldflags)
+
+    elif args.ld_libs:
+        print(builder.get_ld_libs())
+
+    elif args.ar_flags:
+        ar_flags = builder.get_ar_flags()
+        show_command_print_flag_string(args, ar_flags)
+
+    elif args.core_path:
+        print(builder.get_core_path())
+
+    elif args.postbuild:
+        print(builder.get_postbuild_line(args.postbuild))
+
+    elif args.upload_command:
+        print(builder.get_upload_line(args.upload_command, args.serial_port))
+
+    elif args.upload_tools:
+        tools = builder.get_upload_tool_names()
+        for tool_name in tools:
+            print(tool_name)
+
+    elif args.library_includes:
+        show_command_print_string_list(args, builder.library_includes())
+
+    elif args.library_c_files:
+        show_command_print_string_list(args, builder.library_c_files())
+
+    elif args.library_cpp_files:
+        show_command_print_string_list(args, builder.library_cpp_files())
+
+    elif args.core_c_files:
+        show_command_print_string_list(args, builder.core_c_files())
+
+    elif args.core_s_files:
+        show_command_print_string_list(args, builder.core_s_files())
+
+    elif args.core_cpp_files:
+        show_command_print_string_list(args, builder.core_cpp_files())
+
+    elif args.variant_c_files:
+        vfiles = builder.variant_c_files()
+        if vfiles:
+            show_command_print_string_list(args, vfiles)
+
+    elif args.variant_s_files:
+        vfiles = builder.variant_s_files()
+        if vfiles:
+            show_command_print_string_list(args, vfiles)
+
+    elif args.variant_cpp_files:
+        vfiles = builder.variant_cpp_files()
+        if vfiles:
+            show_command_print_string_list(args, vfiles)
+
+
+def add_common_options(parser, serial_port, build_path, build_project_name,
+                       project_path, project_source_path):
+    """Add command line options common to the run and show commands."""
+    parser.add_argument(
+        "--serial-port",
+        default=serial_port,
+        help="Serial port for flashing flash. Default: '{}'".format(
+            serial_port))
+    parser.add_argument(
+        "--build-path",
+        default=build_path,
+        help="Build directory. Default: '{}'".format(build_path))
+    parser.add_argument(
+        "--project-path",
+        default=project_path,
+        help="Project directory. Default: '{}'".format(project_path))
+    parser.add_argument(
+        "--project-source-path",
+        default=project_source_path,
+        help="Project directory. Default: '{}'".format(project_source_path))
+    parser.add_argument(
+        "--build-project-name",
+        default=build_project_name,
+        help="Project name. Default: '{}'".format(build_project_name))
+    parser.add_argument("--board",
+                        required=True,
+                        help="Name of the board to use.")
+    # nargs="+" is one or more args, e.g:
+    #   --menu-options menu.usb.serialhid menu.speed.150
+    parser.add_argument("--menu-options", nargs="+", type=str)
+
+
+def main():
+    """Main command line function.
+
+    Parses command line args and dispatches to sub `*_command()` functions.
+    """
+    def log_level(arg: str) -> int:
+        try:
+            return getattr(logging, arg.upper())
+        except AttributeError:
+            raise argparse.ArgumentTypeError(
+                f'{arg.upper()} is not a valid log level')
+
+    parser = argparse.ArgumentParser()
+    parser.add_argument("-q",
+                        "--quiet",
+                        help="hide run command output",
+                        action="store_true")
+    parser.add_argument('-l',
+                        '--loglevel',
+                        type=log_level,
+                        default=logging.INFO,
+                        help='Set the log level '
+                        '(debug, info, warning, error, critical)')
+
+    build_path = os.path.realpath(
+        os.path.expanduser(os.path.expandvars("./build")))
+    project_path = os.path.realpath(
+        os.path.expanduser(os.path.expandvars("./")))
+    project_source_path = os.path.join(project_path, "src")
+    build_project_name = os.path.basename(project_path)
+
+    serial_port = "UNKNOWN"
+    # TODO(tonymd): Temp solution to passing in serial port. It should use
+    # arduino core discovery tools.
+    possible_serial_ports = glob.glob("/dev/ttyACM*") + glob.glob(
+        "/dev/ttyUSB*")
+    if possible_serial_ports:
+        serial_port = possible_serial_ports[0]
+
+    # Global command line options
+    parser.add_argument("--arduino-package-path",
+                        help="Path to the arduino IDE install location.")
+    parser.add_argument("--arduino-package-name",
+                        help="Name of the Arduino board package to use.")
+    parser.add_argument("--compiler-path-override",
+                        help="Path to arm-none-eabi-gcc bin folder. "
+                        "Default: Arduino core specified gcc")
+
+    # Subcommands
+    subparsers = parser.add_subparsers(title="subcommand",
+                                       description="valid subcommands",
+                                       help="sub-command help",
+                                       dest="subcommand",
+                                       required=True)
+
+    # install-core command
+    install_core_parser = subparsers.add_parser(
+        "install-core", help="Download and install arduino cores")
+    install_core_parser.set_defaults(func=core_installer.install_core_command)
+    install_core_parser.add_argument("--prefix",
+                                     required=True,
+                                     help="Path to install core files.")
+    install_core_parser.add_argument(
+        "--core-name",
+        required=True,
+        choices=core_installer.supported_cores(),
+        help="Name of the arduino core to install.")
+
+    # list-boards command
+    list_boards_parser = subparsers.add_parser("list-boards",
+                                               help="show supported boards")
+    list_boards_parser.set_defaults(func=list_boards_command)
+
+    # list-menu-options command
+    list_menu_options_parser = subparsers.add_parser(
+        "list-menu-options",
+        help="show available menu options for selected board")
+    list_menu_options_parser.set_defaults(func=list_menu_options_command)
+    list_menu_options_parser.add_argument("--board",
+                                          required=True,
+                                          help="Name of the board to use.")
+
+    # show command
+    show_parser = subparsers.add_parser("show",
+                                        help="Return compiler information.")
+    add_common_options(show_parser, serial_port, build_path,
+                       build_project_name, project_path, project_source_path)
+    show_parser.add_argument("--delimit-with-newlines",
+                             help="Separate flag output with newlines.",
+                             action="store_true")
+
+    output_group = show_parser.add_mutually_exclusive_group(required=True)
+    output_group.add_argument("--c-compile", action="store_true")
+    output_group.add_argument("--cpp-compile", action="store_true")
+    output_group.add_argument("--link", action="store_true")
+    output_group.add_argument("--c-flags", action="store_true")
+    output_group.add_argument("--s-flags", action="store_true")
+    output_group.add_argument("--cpp-flags", action="store_true")
+    output_group.add_argument("--ld-flags", action="store_true")
+    output_group.add_argument("--ar-flags", action="store_true")
+    output_group.add_argument("--ld-libs", action="store_true")
+    output_group.add_argument("--objcopy", help="objcopy step for SUFFIX")
+    output_group.add_argument("--objcopy-flags",
+                              help="objcopy flags for SUFFIX")
+    output_group.add_argument("--core-path", action="store_true")
+    output_group.add_argument("--cc-binary", action="store_true")
+    output_group.add_argument("--cxx-binary", action="store_true")
+    output_group.add_argument("--ar-binary", action="store_true")
+    output_group.add_argument("--objcopy-binary", action="store_true")
+    output_group.add_argument("--size-binary", action="store_true")
+    output_group.add_argument("--postbuild",
+                              help="Show recipe.hooks.postbuild.*.pattern")
+    output_group.add_argument("--upload-tools", action="store_true")
+    output_group.add_argument("--upload-command")
+    output_group.add_argument("--library-includes", action="store_true")
+    output_group.add_argument("--library-c-files", action="store_true")
+    output_group.add_argument("--library-cpp-files", action="store_true")
+    output_group.add_argument("--core-c-files", action="store_true")
+    output_group.add_argument("--core-s-files", action="store_true")
+    output_group.add_argument("--core-cpp-files", action="store_true")
+    output_group.add_argument("--variant-c-files", action="store_true")
+    output_group.add_argument("--variant-s-files", action="store_true")
+    output_group.add_argument("--variant-cpp-files", action="store_true")
+
+    show_parser.set_defaults(func=show_command)
+
+    # run command
+    run_parser = subparsers.add_parser("run", help="Run Arduino recipes.")
+    add_common_options(run_parser, serial_port, build_path, build_project_name,
+                       project_path, project_source_path)
+    run_parser.add_argument("--run-link",
+                            nargs="+",
+                            type=str,
+                            help="Run the link command. Expected arguments: "
+                            "the archive file followed by all obj files.")
+    run_parser.add_argument("--run-objcopy", action="store_true")
+    run_parser.add_argument("--run-prebuilds", action="store_true")
+    run_parser.add_argument("--run-postbuilds", action="store_true")
+    run_parser.add_argument("--run-upload-command")
+
+    run_parser.set_defaults(func=run_command)
+
+    args = parser.parse_args()
+
+    log.install()
+    log.set_level(args.loglevel)
+
+    _LOG.debug(_pretty_format(args))
+
+    # Check for and set alternate compiler path.
+    compiler_path_override = False
+    if args.compiler_path_override:
+        compiler_path_override = os.path.realpath(
+            os.path.expanduser(os.path.expandvars(
+                args.compiler_path_override)))
+
+    if args.subcommand == "install-core":
+        args.func(args)
+    elif args.subcommand in ["list-boards", "list-menu-options"]:
+        builder = ArduinoBuilder(args.arduino_package_path,
+                                 args.arduino_package_name)
+        builder.load_board_definitions()
+        args.func(args, builder)
+    else:
+        builder = ArduinoBuilder(args.arduino_package_path,
+                                 args.arduino_package_name,
+                                 build_path=args.build_path,
+                                 build_project_name=args.build_project_name,
+                                 project_path=args.project_path,
+                                 project_source_path=args.project_source_path,
+                                 compiler_path_override=compiler_path_override)
+        builder.load_board_definitions()
+        builder.select_board(args.board, args.menu_options)
+        args.func(args, builder)
+
+    sys.exit(0)
+
+
+if __name__ == '__main__':
+    main()
diff --git a/pw_arduino_build/py/pw_arduino_build/arduinobuilder.py b/pw_arduino_build/py/pw_arduino_build/builder.py
index 239517d64..06c4117cb 100755
--- a/pw_arduino_build/py/pw_arduino_build/arduinobuilder.py
+++ b/pw_arduino_build/py/pw_arduino_build/builder.py
@@ -14,130 +14,23 @@
 # the License.
 """Extracts build information from Arduino cores."""
 
-import argparse
 import glob
-import hashlib
 import logging
 import os
 import platform
 import pprint
 import re
-import shutil
-import shlex
-import stat
 import sys
-import tarfile
 import time
-import urllib.request
-import zipfile
 from collections import OrderedDict
-from pathlib import Path
-from typing import List, Dict
+from typing import List
+
+from pw_arduino_build import file_operations
 
 _LOG = logging.getLogger(__name__)
-_STDERR_HANDLER = logging.StreamHandler()
 
 _pretty_print = pprint.PrettyPrinter(indent=1, width=120).pprint
 _pretty_format = pprint.PrettyPrinter(indent=1, width=120).pformat
-# yapf: disable
-_ARDUINO_CORE_ARTIFACTS = {
-    # pylint: disable=line-too-long
-    "teensy": {
-        "Linux": {
-            "arduino-ide": {
-                "url": "https://downloads.arduino.cc/arduino-1.8.13-linux64.tar.xz",
-                "file_name": "arduino-1.8.13-linux64.tar.xz",
-                "sha256": "1b20d0ec850a2a63488009518725f058668bb6cb48c321f82dcf47dc4299b4ad",
-            },
-            "teensyduino": {
-                "url": "https://www.pjrc.com/teensy/td_153/TeensyduinoInstall.linux64",
-                "file_name": "TeensyduinoInstall.linux64",
-                "sha256": "2e6cd99a757bc80593ea3de006de4cc934bcb0a6ec74cad8ec327f0289d40f0b",
-            },
-        },
-        # TODO(tonymd): Handle 32-bit Linux Install?
-        "Linux32": {
-            "arduino-ide": {
-                "url": "https://downloads.arduino.cc/arduino-1.8.13-linux32.tar.xz",
-                "file_name": "arduino-1.8.13-linux32.tar.xz",
-                "sha256": "",
-            },
-            "teensyduino": {
-                "url": "https://www.pjrc.com/teensy/td_153/TeensyduinoInstall.linux32",
-                "file_name": "TeensyduinoInstall.linux32",
-                "sha256": "",
-            },
-        },
-        # TODO(tonymd): Handle ARM32 (Raspberry Pi) Install?
-        "LinuxARM32": {
-            "arduino-ide": {
-                "url": "https://downloads.arduino.cc/arduino-1.8.13-linuxarm.tar.xz",
-                "file_name": "arduino-1.8.13-linuxarm.tar.xz",
-                "sha256": "",
-            },
-            "teensyduino": {
-                "url": "https://www.pjrc.com/teensy/td_153/TeensyduinoInstall.linuxarm",
-                "file_name": "TeensyduinoInstall.linuxarm",
-                "sha256": "",
-            },
-        },
-        # TODO(tonymd): Handle ARM64 Install?
-        "LinuxARM64": {
-            "arduino-ide": {
-                "url": "https://downloads.arduino.cc/arduino-1.8.13-linuxaarch64.tar.xz",
-                "file_name": "arduino-1.8.13-linuxaarch64.tar.xz",
-                "sha256": "",
-            },
-            "teensyduino": {
-                "url": "https://www.pjrc.com/teensy/td_153/TeensyduinoInstall.linuxaarch64",
-                "file_name": "TeensyduinoInstall.linuxaarch64",
-                "sha256": "",
-            },
-        },
-        "Darwin": {
-            "teensyduino": {
-                "url": "https://www.pjrc.com/teensy/td_153/Teensyduino_MacOS_Catalina.zip",
-                "file_name": "Teensyduino_MacOS_Catalina.zip",
-                "sha256": "401ef42c6e83e621cdda20191a4ef9b7db8a214bede5a94a9e26b45f79c64fe2",
-            },
-        },
-        "Windows": {
-            "arduino-ide": {
-                "url": "https://downloads.arduino.cc/arduino-1.8.13-windows.zip",
-                "file_name": "arduino-1.8.13-windows.zip",
-                "sha256": "78d3e96827b9e9b31b43e516e601c38d670d29f12483e88cbf6d91a0f89ef524",
-            },
-            "teensyduino": {
-                "url": "https://www.pjrc.com/teensy/td_153/TeensyduinoInstall.exe",
-                "file_name": "TeensyduinoInstall.exe",
-                "sha256": "88f58681e5c4772c54e462bc88280320e4276e5b316dcab592fe38d96db990a1",
-            },
-        }
-    },
-    "adafruit-samd": {
-        "all": {
-            "core": {
-                "url": "https://github.com/adafruit/ArduinoCore-samd/archive/1.6.2.tar.gz",
-                "sha256": "5875f5bc05904c10e6313f02653f28f2f716db639d3d43f5a1d8a83d15339d64",
-            }
-        },
-        "Linux": {},
-        "Darwin": {},
-        "Windows": {},
-    },
-    "stm32duino": {
-        "all": {
-            "core": {
-                "url": "https://github.com/stm32duino/Arduino_Core_STM32/archive/1.9.0.tar.gz",
-                "sha256": "4f75ba7a117d90392e8f67c58d31d22393749b9cdd3279bc21e7261ec06c62bf",
-            }
-        },
-        "Linux": {},
-        "Darwin": {},
-        "Windows": {},
-    },
-} # type: Dict[str, Dict]
-# yapf: enable
 
 
 def arduino_runtime_os_string():
@@ -149,327 +42,6 @@ def arduino_runtime_os_string():
     return arduno_platform[platform.system()]
 
 
-class FileOperations:
-    """File helper functions."""
-    @staticmethod
-    def find_files(starting_dir: str,
-                   patterns: List[str],
-                   directories_only=False) -> List[str]:
-        # ["**/*.S", "**/*.ino", "**/*.h", "**/*.c", "**/*.cpp"]
-
-        original_working_dir = os.getcwd()
-        if not (os.path.exists(starting_dir) and os.path.isdir(starting_dir)):
-            _LOG.error("Directory '%s' does not exist.", starting_dir)
-            raise FileNotFoundError
-
-        os.chdir(starting_dir)
-        files = []
-        for pattern in patterns:
-            for file_path in glob.glob(pattern, recursive=True):
-                if not directories_only or (directories_only
-                                            and os.path.isdir(file_path)):
-                    files.append(file_path)
-        os.chdir(original_working_dir)
-        return sorted(files)
-
-    @staticmethod
-    def sha256_sum(file_name):
-        hash_sha256 = hashlib.sha256()
-        with open(file_name, "rb") as file_handle:
-            for chunk in iter(lambda: file_handle.read(4096), b""):
-                hash_sha256.update(chunk)
-        return hash_sha256.hexdigest()
-
-    @staticmethod
-    def md5_sum(file_name):
-        hash_md5 = hashlib.md5()
-        with open(file_name, "rb") as file_handle:
-            for chunk in iter(lambda: file_handle.read(4096), b""):
-                hash_md5.update(chunk)
-        return hash_md5.hexdigest()
-
-    @staticmethod
-    def verify_file_checksum(file_path,
-                             expected_checksum,
-                             sum_function=sha256_sum):
-        downloaded_checksum = sum_function(file_path)
-        if downloaded_checksum != expected_checksum:
-            _LOG.error("Error: Invalid %s", sum_function.__name__)
-            _LOG.error("%s %s", downloaded_checksum,
-                       os.path.basename(file_path))
-            _LOG.error("%s (expected)", expected_checksum)
-            return sys.exit(1)
-
-        _LOG.info("  %s:", sum_function.__name__)
-        _LOG.info("  %s %s", downloaded_checksum, os.path.basename(file_path))
-        return True
-
-    @staticmethod
-    def download_to_cache(url: str,
-                          expected_md5sum=None,
-                          expected_sha256sum=None,
-                          cache_directory=".cache") -> str:
-
-        cache_dir = os.path.realpath(
-            os.path.expanduser(os.path.expandvars(cache_directory)))
-        downloaded_file = os.path.join(cache_dir, url.split("/")[-1])
-
-        if not os.path.exists(downloaded_file):
-            _LOG.info("Downloading: %s", url)
-            urllib.request.urlretrieve(url, filename=downloaded_file)
-
-        if os.path.exists(downloaded_file):
-            _LOG.info("Downloaded: %s", downloaded_file)
-            if expected_sha256sum:
-                FileOperations.verify_file_checksum(
-                    downloaded_file,
-                    expected_sha256sum,
-                    sum_function=FileOperations.sha256_sum)
-            elif expected_md5sum:
-                FileOperations.verify_file_checksum(
-                    downloaded_file,
-                    expected_md5sum,
-                    sum_function=FileOperations.md5_sum)
-
-        return downloaded_file
-
-    @staticmethod
-    def extract_zipfile(archive_file: str, dest_dir: str):
-        with zipfile.ZipFile(archive_file) as archive:
-            archive.extractall(path=dest_dir)
-
-    @staticmethod
-    def extract_tarfile(archive_file: str, dest_dir: str):
-        with tarfile.open(archive_file, 'r') as archive:
-            archive.extractall(path=dest_dir)
-
-    @staticmethod
-    def extract_archive(archive_file: str,
-                        dest_dir: str,
-                        cache_dir: str,
-                        remove_single_toplevel_folder=True):
-        """Extract a tar or zip file.
-
-        Args:
-            archive_file (str): Absolute path to the archive file.
-            dest_dir (str): Extraction destination directory.
-            cache_dir (str): Directory where temp files can be created.
-            remove_single_toplevel_folder (bool): If the archive contains only a
-                single folder move the contents of that into the destination
-                directory.
-        """
-        # Make a temporary directory to extract files into
-        temp_extract_dir = os.path.join(cache_dir,
-                                        "." + os.path.basename(archive_file))
-        os.makedirs(temp_extract_dir, exist_ok=True)
-
-        _LOG.info("Extracting: %s", archive_file)
-        if zipfile.is_zipfile(archive_file):
-            FileOperations.extract_zipfile(archive_file, temp_extract_dir)
-        elif tarfile.is_tarfile(archive_file):
-            FileOperations.extract_tarfile(archive_file, temp_extract_dir)
-        else:
-            _LOG.error("Unknown archive format: %s", archive_file)
-            return sys.exit(1)
-
-        _LOG.info("Installing into: %s", dest_dir)
-        path_to_extracted_files = temp_extract_dir
-
-        extracted_top_level_files = os.listdir(temp_extract_dir)
-        # Check if tarfile has only one folder
-        # If yes, make that the new path_to_extracted_files
-        if remove_single_toplevel_folder and len(
-                extracted_top_level_files) == 1:
-            path_to_extracted_files = os.path.join(
-                temp_extract_dir, extracted_top_level_files[0])
-
-        # Move extracted files to dest_dir
-        extracted_files = os.listdir(path_to_extracted_files)
-        for file_name in extracted_files:
-            source_file = os.path.join(path_to_extracted_files, file_name)
-            dest_file = os.path.join(dest_dir, file_name)
-            shutil.move(source_file, dest_file)
-
-        # rm -rf temp_extract_dir
-        shutil.rmtree(temp_extract_dir, ignore_errors=True)
-
-        # Return List of extracted files
-        return list(Path(dest_dir).rglob("*"))
-
-    @staticmethod
-    def remove_empty_directories(directory):
-        """Recursively remove empty directories."""
-
-        for path in sorted(Path(directory).rglob("*"), reverse=True):
-            # If broken symlink
-            if path.is_symlink() and not path.exists():
-                path.unlink()
-            # if empty directory
-            elif path.is_dir() and len(os.listdir(path)) == 0:
-                path.rmdir()
-
-
-class ArduinoCoreInstaller:
-    """Simple Arduino core installer."""
-    @staticmethod
-    def install_teensy_core_windows(install_prefix, install_dir, cache_dir):
-        """Download and install Teensyduino artifacts for Windows."""
-        teensy_artifacts = _ARDUINO_CORE_ARTIFACTS["teensy"][platform.system()]
-
-        arduino_artifact = teensy_artifacts["arduino-ide"]
-        arduino_zipfile = FileOperations.download_to_cache(
-            url=arduino_artifact["url"],
-            expected_sha256sum=arduino_artifact["sha256"],
-            cache_directory=cache_dir)
-
-        teensyduino_artifact = teensy_artifacts["teensyduino"]
-        teensyduino_installer = FileOperations.download_to_cache(
-            url=teensyduino_artifact["url"],
-            expected_sha256sum=teensyduino_artifact["sha256"],
-            cache_directory=cache_dir)
-
-        FileOperations.extract_archive(arduino_zipfile, install_dir, cache_dir)
-
-        # "teensy" here should match args.core_name
-        teensy_core_dir = os.path.join(install_prefix, "teensy")
-
-        # Change working directory for installation
-        original_working_dir = os.getcwd()
-        os.chdir(install_prefix)
-
-        _LOG.info("Installing Teensyduino to: %s", teensy_core_dir)
-
-        install_command = "{} \"--dir={}\"".format(teensyduino_installer,
-                                                   "teensy")
-        _LOG.info("  Running: %s", install_command)
-        _LOG.info("  Please click yes on the Windows 'User Account Control' "
-                  "dialog.")
-        _LOG.info("  You should see: 'Verified publisher: PRJC.COM LLC'")
-
-        os.system(install_command)
-        if not os.path.exists(
-                os.path.join(teensy_core_dir, "hardware", "teensy")):
-            _LOG.error(
-                "Error: Installation Failed.\n"
-                "Please try again and ensure Teensyduino is installed in "
-                "the folder:\n"
-                "%s", teensy_core_dir)
-            sys.exit(1)
-        else:
-            _LOG.info("  Install complete!")
-
-        FileOperations.remove_empty_directories(install_dir)
-        os.chdir(original_working_dir)
-
-    @staticmethod
-    def install_teensy_core_mac(unused_install_prefix, install_dir, cache_dir):
-        """Download and install Teensyduino artifacts for Mac."""
-        teensy_artifacts = _ARDUINO_CORE_ARTIFACTS["teensy"][platform.system()]
-
-        teensyduino_artifact = teensy_artifacts["teensyduino"]
-        teensyduino_zip = FileOperations.download_to_cache(
-            url=teensyduino_artifact["url"],
-            expected_sha256sum=teensyduino_artifact["sha256"],
-            cache_directory=cache_dir)
-
-        extracted_files = FileOperations.extract_archive(
-            teensyduino_zip,
-            install_dir,
-            cache_dir,
-            remove_single_toplevel_folder=False)
-        toplevel_folder = sorted(extracted_files)[0]
-        os.symlink(os.path.join(toplevel_folder, "Contents", "Java",
-                                "hardware"),
-                   os.path.join(install_dir, "hardware"),
-                   target_is_directory=True)
-
-    @staticmethod
-    def install_teensy_core_linux(install_prefix, install_dir, cache_dir):
-        """Download and install Teensyduino artifacts for Windows."""
-        teensy_artifacts = _ARDUINO_CORE_ARTIFACTS["teensy"][platform.system()]
-
-        arduino_artifact = teensy_artifacts["arduino-ide"]
-        arduino_tarfile = FileOperations.download_to_cache(
-            url=arduino_artifact["url"],
-            expected_sha256sum=arduino_artifact["sha256"],
-            cache_directory=cache_dir)
-
-        teensyduino_artifact = teensy_artifacts["teensyduino"]
-        teensyduino_installer = FileOperations.download_to_cache(
-            url=teensyduino_artifact["url"],
-            expected_sha256sum=teensyduino_artifact["sha256"],
-            cache_directory=cache_dir)
-
-        extracted_files = FileOperations.extract_archive(
-            arduino_tarfile, install_dir, cache_dir)
-        os.chmod(teensyduino_installer,
-                 os.stat(teensyduino_installer).st_mode | stat.S_IEXEC)
-
-        original_working_dir = os.getcwd()
-        os.chdir(install_prefix)
-        # "teensy" here should match args.core_name
-        os.system("{} --dir={}".format(teensyduino_installer, "teensy"))
-
-        # Remove original arduino IDE files
-        for efile in extracted_files:
-            if efile.is_file():
-                efile.unlink()
-
-        FileOperations.remove_empty_directories(install_dir)
-        os.chdir(original_working_dir)
-
-    @staticmethod
-    def install_arduino_samd_core(install_prefix: str, install_dir: str,
-                                  cache_dir: str):
-        # TODO(tonymd): Fetch core/tools as specified by:
-        # http://downloads.arduino.cc/packages/package_index.json
-        pass
-
-    @staticmethod
-    def install_adafruit_samd_core(install_prefix: str, install_dir: str,
-                                   cache_dir: str):
-        artifacts = _ARDUINO_CORE_ARTIFACTS["adafruit-samd"]["all"]["core"]
-        core_tarfile = FileOperations.download_to_cache(
-            url=artifacts["url"],
-            expected_sha256sum=artifacts["sha256"],
-            cache_directory=cache_dir)
-
-        package_path = os.path.join(
-            install_dir, "hardware", "samd",
-            os.path.basename(core_tarfile).replace(".tar.gz", ""))
-        os.makedirs(package_path, exist_ok=True)
-        FileOperations.extract_archive(core_tarfile, package_path, cache_dir)
-
-        original_working_dir = os.getcwd()
-        os.chdir(install_prefix)
-        # TODO(tonymd): Fetch platform specific tools as specified by:
-        # https://adafruit.github.io/arduino-board-index/package_adafruit_index.json
-        # Specifically:
-        #   https://github.com/ARM-software/CMSIS_5/archive/5.4.0.tar.gz
-        os.chdir(original_working_dir)
-        return True
-
-    @staticmethod
-    def install_stm32duino_core(install_prefix, install_dir, cache_dir):
-        artifacts = _ARDUINO_CORE_ARTIFACTS["stm32duino"]["all"]["core"]
-        core_tarfile = FileOperations.download_to_cache(
-            url=artifacts["url"],
-            expected_sha256sum=artifacts["sha256"],
-            cache_directory=cache_dir)
-
-        package_path = os.path.join(
-            install_dir, "hardware", "stm32",
-            os.path.basename(core_tarfile).replace(".tar.gz", ""))
-        os.makedirs(package_path, exist_ok=True)
-        FileOperations.extract_archive(core_tarfile, package_path, cache_dir)
-        original_working_dir = os.getcwd()
-        os.chdir(install_prefix)
-        # TODO(tonymd): Fetch platform specific tools as specified by:
-        # https://github.com/stm32duino/BoardManagerFiles/raw/master/STM32/package_stm_index.json
-        os.chdir(original_working_dir)
-        return True
-
-
 class ArduinoBuilder:
     """Used to interpret arduino boards.txt and platform.txt files."""
     # pylint: disable=too-many-instance-attributes,too-many-public-methods
@@ -517,7 +89,7 @@ class ArduinoBuilder:
 
         self.compiler_path_override_binaries = []
         if self.compiler_path_override:
-            self.compiler_path_override_binaries = FileOperations.find_files(
+            self.compiler_path_override_binaries = file_operations.find_files(
                 self.compiler_path_override, "*")
 
         # Container dicts for boards.txt and platform.txt file data.
@@ -1372,8 +944,8 @@ class ArduinoBuilder:
 
         library_path = os.path.join(self.project_path, "libraries")
 
-        library_folders = FileOperations.find_files(library_path, ["*"],
-                                                    directories_only=True)
+        library_folders = file_operations.find_files(library_path, ["*"],
+                                                     directories_only=True)
         library_source_root_folders = []
         for lib in library_folders:
             lib_dir = os.path.join(library_path, lib)
@@ -1396,7 +968,7 @@ class ArduinoBuilder:
         sources = []
         library_folders = self.library_folders()
         for lib_dir in library_folders:
-            for file_path in FileOperations.find_files(lib_dir, [pattern]):
+            for file_path in file_operations.find_files(lib_dir, [pattern]):
                 if not file_path.startswith("examples"):
                     sources.append(
                         os.path.relpath(os.path.join(lib_dir, file_path)))
@@ -1413,8 +985,8 @@ class ArduinoBuilder:
 
     def core_files(self, pattern):
         sources = []
-        for file_path in FileOperations.find_files(self.get_core_path(),
-                                                   [pattern]):
+        for file_path in file_operations.find_files(self.get_core_path(),
+                                                    [pattern]):
             sources.append(os.path.join(self.get_core_path(), file_path))
         return sources
 
@@ -1433,8 +1005,8 @@ class ArduinoBuilder:
     def variant_files(self, pattern):
         sources = []
         if self.build_variant_path:
-            for file_path in FileOperations.find_files(self.get_variant_path(),
-                                                       [pattern]):
+            for file_path in file_operations.find_files(
+                    self.get_variant_path(), [pattern]):
                 sources.append(os.path.join(self.get_variant_path(),
                                             file_path))
         return sources
@@ -1450,8 +1022,8 @@ class ArduinoBuilder:
 
     def project_files(self, pattern):
         sources = []
-        for file_path in FileOperations.find_files(self.project_path,
-                                                   [pattern]):
+        for file_path in file_operations.find_files(self.project_path,
+                                                    [pattern]):
             if not file_path.startswith(
                     "examples") and not file_path.startswith("libraries"):
                 sources.append(file_path)
@@ -1465,430 +1037,3 @@ class ArduinoBuilder:
 
     def project_ino_files(self):
         return self.project_files("**/*.ino")
-
-
-def install_core_command(args):
-    install_prefix = os.path.realpath(
-        os.path.expanduser(os.path.expandvars(args.prefix)))
-    install_dir = os.path.join(install_prefix, args.core_name)
-    cache_dir = os.path.join(install_prefix, ".cache", args.core_name)
-
-    shutil.rmtree(install_dir, ignore_errors=True)
-    os.makedirs(install_dir, exist_ok=True)
-    os.makedirs(cache_dir, exist_ok=True)
-
-    if args.core_name == "teensy":
-        if platform.system() == "Linux":
-            ArduinoCoreInstaller.install_teensy_core_linux(
-                install_prefix, install_dir, cache_dir)
-        elif platform.system() == "Darwin":
-            ArduinoCoreInstaller.install_teensy_core_mac(
-                install_prefix, install_dir, cache_dir)
-        elif platform.system() == "Windows":
-            ArduinoCoreInstaller.install_teensy_core_windows(
-                install_prefix, install_dir, cache_dir)
-    elif args.core_name == "adafruit-samd":
-        ArduinoCoreInstaller.install_adafruit_samd_core(
-            install_prefix, install_dir, cache_dir)
-    elif args.core_name == "stm32duino":
-        ArduinoCoreInstaller.install_stm32duino_core(install_prefix,
-                                                     install_dir, cache_dir)
-
-    sys.exit(0)
-
-
-def list_boards_command(unused_args, builder):
-    # list-boards subcommand
-    # (does not need a selected board or default menu options)
-
-    # TODO(tonymd): Print this sorted with auto-ljust columns
-    longest_name_length = 0
-    for board_name, board_dict in builder.board.items():
-        if len(board_name) > longest_name_length:
-            longest_name_length = len(board_name)
-    longest_name_length += 2
-
-    print("Board Name".ljust(longest_name_length), "Description")
-    for board_name, board_dict in builder.board.items():
-        print(board_name.ljust(longest_name_length), board_dict['name'])
-    sys.exit(0)
-
-
-def list_menu_options_command(args, builder):
-    # List all menu options for the selected board.
-    builder.select_board(args.board)
-
-    print("All Options")
-    all_options, all_column_widths = builder.get_menu_options()
-    separator = "-" * (all_column_widths[0] + all_column_widths[1] + 2)
-    print(separator)
-
-    for name, description in all_options:
-        print(name.ljust(all_column_widths[0] + 1), description)
-
-    print("\nDefault Options")
-    print(separator)
-
-    default_options, unused_column_widths = builder.get_default_menu_options()
-    for name, description in default_options:
-        print(name.ljust(all_column_widths[0] + 1), description)
-
-
-def show_command_print_string_list(args, string_list: List[str]):
-    join_token = " "
-    if args.delimit_with_newlines:
-        join_token = "\n"
-    print(join_token.join(string_list))
-
-
-def show_command_print_flag_string(args, flag_string):
-    if args.delimit_with_newlines:
-        flag_string_with_newlines = shlex.split(flag_string)
-        print("\n".join(flag_string_with_newlines))
-    else:
-        print(flag_string)
-
-
-def run_command_lines(args, command_lines: List[str]):
-    for command_line in command_lines:
-        if not args.quiet:
-            print(command_line)
-        # TODO(tonymd): Exit with sub command exit code.
-        os.system(command_line)
-
-
-# pylint: disable=too-many-branches
-def show_command(args, builder):
-    """Show sub command function.
-
-    Prints compile flags and runs Arduino recipes.
-    """
-    builder.select_board(args.board, args.menu_options)
-
-    if args.cc_binary:
-        print(builder.get_cc_binary())
-
-    elif args.cxx_binary:
-        print(builder.get_cxx_binary())
-
-    elif args.objcopy_binary:
-        print(builder.get_objcopy_binary())
-
-    elif args.ar_binary:
-        print(builder.get_ar_binary())
-
-    elif args.size_binary:
-        print(builder.get_size_binary())
-
-    elif args.run_c_compile:
-        print(builder.get_c_compile_line())
-
-    elif args.run_cpp_compile:
-        print(builder.get_cpp_compile_line())
-
-    elif args.run_link:
-        line = builder.get_link_line()
-        archive_file_path = args.run_link[0]  # pylint: disable=unused-variable
-        object_files = args.run_link[1:]
-        line = line.replace("{object_files}", " ".join(object_files), 1)
-        run_command_lines(args, [line])
-
-    elif args.run_objcopy:
-        run_command_lines(args, builder.get_objcopy_steps())
-
-    elif args.objcopy:
-        print(builder.get_objcopy(args.objcopy))
-
-    elif args.objcopy_flags:
-        objcopy_flags = builder.get_objcopy_flags(args.objcopy_flags)
-        show_command_print_flag_string(args, objcopy_flags)
-
-    elif args.c_flags:
-        cflags = builder.get_c_flags()
-        show_command_print_flag_string(args, cflags)
-
-    elif args.s_flags:
-        sflags = builder.get_s_flags()
-        show_command_print_flag_string(args, sflags)
-
-    elif args.cpp_flags:
-        cppflags = builder.get_cpp_flags()
-        show_command_print_flag_string(args, cppflags)
-
-    elif args.ld_flags:
-        ldflags = builder.get_ld_flags()
-        show_command_print_flag_string(args, ldflags)
-
-    elif args.ld_libs:
-        print(builder.get_ld_libs())
-
-    elif args.ar_flags:
-        ar_flags = builder.get_ar_flags()
-        show_command_print_flag_string(args, ar_flags)
-
-    elif args.core_path:
-        print(builder.get_core_path())
-
-    elif args.run_prebuilds:
-        run_command_lines(args, builder.get_prebuild_steps())
-
-    elif args.run_postbuilds:
-        run_command_lines(args, builder.get_postbuild_steps())
-
-    elif args.postbuild:
-        print(builder.get_postbuild_line(args.postbuild))
-
-    elif args.run_upload_command:
-        command = builder.get_upload_line(args.run_upload_command,
-                                          args.serial_port)
-        run_command_lines(args, [command])
-
-    elif args.upload_command:
-        print(builder.get_upload_line(args.upload_command, args.serial_port))
-
-    elif args.upload_tools:
-        tools = builder.get_upload_tool_names()
-        for tool_name in tools:
-            print(tool_name)
-
-    elif args.library_includes:
-        show_command_print_string_list(args, builder.library_includes())
-
-    elif args.library_c_files:
-        show_command_print_string_list(args, builder.library_c_files())
-
-    elif args.library_cpp_files:
-        show_command_print_string_list(args, builder.library_cpp_files())
-
-    elif args.core_c_files:
-        show_command_print_string_list(args, builder.core_c_files())
-
-    elif args.core_s_files:
-        show_command_print_string_list(args, builder.core_s_files())
-
-    elif args.core_cpp_files:
-        show_command_print_string_list(args, builder.core_cpp_files())
-
-    elif args.variant_c_files:
-        vfiles = builder.variant_c_files()
-        if vfiles:
-            show_command_print_string_list(args, vfiles)
-
-    elif args.variant_s_files:
-        vfiles = builder.variant_s_files()
-        if vfiles:
-            show_command_print_string_list(args, vfiles)
-
-    elif args.variant_cpp_files:
-        vfiles = builder.variant_cpp_files()
-        if vfiles:
-            show_command_print_string_list(args, vfiles)
-
-
-def main():
-    """Main command line function.
-
-    Parses command line args and dispatches to sub `*_command()` functions.
-    """
-    def log_level(arg: str) -> int:
-        try:
-            return getattr(logging, arg.upper())
-        except AttributeError:
-            raise argparse.ArgumentTypeError(
-                f'{arg.upper()} is not a valid log level')
-
-    parser = argparse.ArgumentParser()
-    parser.add_argument("-q",
-                        "--quiet",
-                        help="hide run command output",
-                        action="store_true")
-    parser.add_argument('-l',
-                        '--loglevel',
-                        type=log_level,
-                        default=logging.INFO,
-                        help='Set the log level '
-                        '(debug, info, warning, error, critical)')
-
-    build_path = os.path.realpath(
-        os.path.expanduser(os.path.expandvars("./build")))
-    project_path = os.path.realpath(
-        os.path.expanduser(os.path.expandvars("./")))
-    project_source_path = os.path.join(project_path, "src")
-    build_project_name = os.path.basename(project_path)
-
-    serial_port = "UNKNOWN"
-    # TODO(tonymd): Temp solution to passing in serial port. It should use
-    # arduino core discovery tools.
-    possible_serial_ports = glob.glob("/dev/ttyACM*") + glob.glob(
-        "/dev/ttyUSB*")
-    if possible_serial_ports:
-        serial_port = possible_serial_ports[0]
-
-    project_name = os.path.basename(
-        os.path.realpath(os.path.expanduser(os.path.expandvars("./"))))
-
-    # Global command line options
-    parser.add_argument("--arduino-package-path",
-                        help="Path to the arduino IDE install location.")
-    parser.add_argument("--arduino-package-name",
-                        help="Name of the Arduino board package to use.")
-    parser.add_argument("--compiler-path-override",
-                        help="Path to arm-none-eabi-gcc bin folder. "
-                        "Default: Arduino core specified gcc")
-
-    # Subcommands
-    subparsers = parser.add_subparsers(title="subcommand",
-                                       description="valid subcommands",
-                                       help="sub-command help",
-                                       dest="subcommand",
-                                       required=True)
-
-    # install-core command
-    install_core_parser = subparsers.add_parser(
-        "install-core", help="Download and install arduino cores")
-    install_core_parser.set_defaults(func=install_core_command)
-    install_core_parser.add_argument("--prefix",
-                                     required=True,
-                                     help="Path to install core files.")
-    install_core_parser.add_argument(
-        "--core-name",
-        required=True,
-        choices=[
-            "teensy",
-            "stm32duino",
-            "adafruit-samd",
-        ],
-        help="Name of the arduino core to install.")
-
-    # list-boards command
-    list_boards_parser = subparsers.add_parser("list-boards",
-                                               help="show supported boards")
-    list_boards_parser.set_defaults(func=list_boards_command)
-
-    # list-menu-options command
-    list_menu_options_parser = subparsers.add_parser(
-        "list-menu-options",
-        help="show available menu options for selected board")
-    list_menu_options_parser.set_defaults(func=list_menu_options_command)
-    list_menu_options_parser.add_argument("--board",
-                                          required=True,
-                                          help="Name of the board to use.")
-
-    # show command
-    show_parser = subparsers.add_parser("show",
-                                        help="Return compiler information.")
-    show_parser.add_argument(
-        "--serial-port",
-        default=serial_port,
-        help="Serial port for flashing flash. Default: '{}'".format(
-            serial_port))
-    show_parser.add_argument(
-        "--build-path",
-        default=build_path,
-        help="Build directory. Default: '{}'".format(build_path))
-    show_parser.add_argument(
-        "--project-path",
-        default=build_path,
-        help="Project directory. Default: '{}'".format(project_path))
-    show_parser.add_argument(
-        "--project-source-path",
-        default=project_source_path,
-        help="Project directory. Default: '{}'".format(project_source_path))
-    show_parser.add_argument(
-        "--build-project-name",
-        default=project_name,
-        help="Project name. Default: '{}'".format(build_project_name))
-    show_parser.add_argument("--board",
-                             required=True,
-                             help="Name of the board to use.")
-    show_parser.add_argument("--delimit-with-newlines",
-                             help="Separate flags output with newlines.",
-                             action="store_true")
-
-    output_group = show_parser.add_mutually_exclusive_group(required=True)
-    output_group.add_argument("--run-c-compile", action="store_true")
-    output_group.add_argument("--run-cpp-compile", action="store_true")
-    output_group.add_argument("--run-link",
-                              nargs="+",
-                              type=str,
-                              help="Run the link command. Expected arguments: "
-                              "the archive file followed by all obj files.")
-    output_group.add_argument("--run-objcopy", action="store_true")
-    output_group.add_argument("--run-prebuilds", action="store_true")
-    output_group.add_argument("--run-postbuilds", action="store_true")
-    output_group.add_argument("--c-flags", action="store_true")
-    output_group.add_argument("--s-flags", action="store_true")
-    output_group.add_argument("--cpp-flags", action="store_true")
-    output_group.add_argument("--ld-flags", action="store_true")
-    output_group.add_argument("--ar-flags", action="store_true")
-    output_group.add_argument("--ld-libs", action="store_true")
-    output_group.add_argument("--objcopy", help="objcopy step for SUFFIX")
-    output_group.add_argument("--objcopy-flags",
-                              help="objcopy flags for SUFFIX")
-    output_group.add_argument("--core-path", action="store_true")
-    output_group.add_argument("--cc-binary", action="store_true")
-    output_group.add_argument("--cxx-binary", action="store_true")
-    output_group.add_argument("--ar-binary", action="store_true")
-    output_group.add_argument("--objcopy-binary", action="store_true")
-    output_group.add_argument("--size-binary", action="store_true")
-    output_group.add_argument("--postbuild",
-                              help="Show recipe.hooks.postbuild.*.pattern")
-    output_group.add_argument("--upload-tools", action="store_true")
-    output_group.add_argument("--upload-command")
-    output_group.add_argument("--run-upload-command")
-    output_group.add_argument("--library-includes", action="store_true")
-    output_group.add_argument("--library-c-files", action="store_true")
-    output_group.add_argument("--library-cpp-files", action="store_true")
-    output_group.add_argument("--core-c-files", action="store_true")
-    output_group.add_argument("--core-s-files", action="store_true")
-    output_group.add_argument("--core-cpp-files", action="store_true")
-    output_group.add_argument("--variant-c-files", action="store_true")
-    output_group.add_argument("--variant-s-files", action="store_true")
-    output_group.add_argument("--variant-cpp-files", action="store_true")
-
-    # nargs="+" is one or more args, e.g:
-    #   --menu-options menu.usb.serialhid menu.speed.150
-    show_parser.add_argument("--menu-options", nargs="+", type=str)
-    show_parser.set_defaults(func=show_command)
-
-    args = parser.parse_args()
-
-    # Set logging level and output handler
-    _LOG.setLevel(args.loglevel)
-    _STDERR_HANDLER.setLevel(args.loglevel)
-    _STDERR_HANDLER.setFormatter(
-        logging.Formatter("[%(asctime)s] "
-                          "%(levelname)s %(message)s", "%Y%m%d %H:%M:%S"))
-    _LOG.addHandler(_STDERR_HANDLER)
-
-    _LOG.debug(_pretty_format(args))
-
-    compiler_path_override = False
-    if args.compiler_path_override:
-        compiler_path_override = os.path.realpath(
-            os.path.expanduser(os.path.expandvars(
-                args.compiler_path_override)))
-
-    if args.subcommand == "install-core":
-        args.func(args)
-    elif args.subcommand in ["list-boards", "list-menu-options"]:
-        builder = ArduinoBuilder(args.arduino_package_path,
-                                 args.arduino_package_name)
-        builder.load_board_definitions()
-        args.func(args, builder)
-    else:
-        builder = ArduinoBuilder(args.arduino_package_path,
-                                 args.arduino_package_name,
-                                 build_path=args.build_path,
-                                 build_project_name=args.build_project_name,
-                                 project_path=args.project_path,
-                                 project_source_path=args.project_source_path,
-                                 compiler_path_override=compiler_path_override)
-        builder.load_board_definitions()
-        args.func(args, builder)
-
-    sys.exit(0)
-
-
-if __name__ == '__main__':
-    main()
diff --git a/pw_arduino_build/py/pw_arduino_build/core_installer.py b/pw_arduino_build/py/pw_arduino_build/core_installer.py
new file mode 100644
index 000000000..a1e3d3c74
--- /dev/null
+++ b/pw_arduino_build/py/pw_arduino_build/core_installer.py
@@ -0,0 +1,346 @@
+#!/usr/bin/env python3
+# Copyright 2020 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+"""Arduino Core Installer."""
+
+import argparse
+import logging
+import os
+import platform
+import stat
+import sys
+import shutil
+import subprocess
+from typing import Dict
+
+import pw_arduino_build.file_operations as file_operations
+
+_LOG = logging.getLogger(__name__)
+
+# yapf: disable
+_ARDUINO_CORE_ARTIFACTS: Dict[str, Dict] = {
+    # pylint: disable=line-too-long
+    "teensy": {
+        "Linux": {
+            "arduino-ide": {
+                "url": "https://downloads.arduino.cc/arduino-1.8.13-linux64.tar.xz",
+                "file_name": "arduino-1.8.13-linux64.tar.xz",
+                "sha256": "1b20d0ec850a2a63488009518725f058668bb6cb48c321f82dcf47dc4299b4ad",
+            },
+            "teensyduino": {
+                "url": "https://www.pjrc.com/teensy/td_153/TeensyduinoInstall.linux64",
+                "file_name": "TeensyduinoInstall.linux64",
+                "sha256": "2e6cd99a757bc80593ea3de006de4cc934bcb0a6ec74cad8ec327f0289d40f0b",
+            },
+        },
+        # TODO(tonymd): Handle 32-bit Linux Install?
+        "Linux32": {
+            "arduino-ide": {
+                "url": "https://downloads.arduino.cc/arduino-1.8.13-linux32.tar.xz",
+                "file_name": "arduino-1.8.13-linux32.tar.xz",
+                "sha256": "",
+            },
+            "teensyduino": {
+                "url": "https://www.pjrc.com/teensy/td_153/TeensyduinoInstall.linux32",
+                "file_name": "TeensyduinoInstall.linux32",
+                "sha256": "",
+            },
+        },
+        # TODO(tonymd): Handle ARM32 (Raspberry Pi) Install?
+        "LinuxARM32": {
+            "arduino-ide": {
+                "url": "https://downloads.arduino.cc/arduino-1.8.13-linuxarm.tar.xz",
+                "file_name": "arduino-1.8.13-linuxarm.tar.xz",
+                "sha256": "",
+            },
+            "teensyduino": {
+                "url": "https://www.pjrc.com/teensy/td_153/TeensyduinoInstall.linuxarm",
+                "file_name": "TeensyduinoInstall.linuxarm",
+                "sha256": "",
+            },
+        },
+        # TODO(tonymd): Handle ARM64 Install?
+        "LinuxARM64": {
+            "arduino-ide": {
+                "url": "https://downloads.arduino.cc/arduino-1.8.13-linuxaarch64.tar.xz",
+                "file_name": "arduino-1.8.13-linuxaarch64.tar.xz",
+                "sha256": "",
+            },
+            "teensyduino": {
+                "url": "https://www.pjrc.com/teensy/td_153/TeensyduinoInstall.linuxaarch64",
+                "file_name": "TeensyduinoInstall.linuxaarch64",
+                "sha256": "",
+            },
+        },
+        "Darwin": {
+            "teensyduino": {
+                "url": "https://www.pjrc.com/teensy/td_153/Teensyduino_MacOS_Catalina.zip",
+                "file_name": "Teensyduino_MacOS_Catalina.zip",
+                "sha256": "401ef42c6e83e621cdda20191a4ef9b7db8a214bede5a94a9e26b45f79c64fe2",
+            },
+        },
+        "Windows": {
+            "arduino-ide": {
+                "url": "https://downloads.arduino.cc/arduino-1.8.13-windows.zip",
+                "file_name": "arduino-1.8.13-windows.zip",
+                "sha256": "78d3e96827b9e9b31b43e516e601c38d670d29f12483e88cbf6d91a0f89ef524",
+            },
+            "teensyduino": {
+                "url": "https://www.pjrc.com/teensy/td_153/TeensyduinoInstall.exe",
+                "file_name": "TeensyduinoInstall.exe",
+                "sha256": "88f58681e5c4772c54e462bc88280320e4276e5b316dcab592fe38d96db990a1",
+            },
+        }
+    },
+    "adafruit-samd": {
+        "all": {
+            "core": {
+                "version": "1.6.2",
+                "url": "https://github.com/adafruit/ArduinoCore-samd/archive/1.6.2.tar.gz",
+                "sha256": "5875f5bc05904c10e6313f02653f28f2f716db639d3d43f5a1d8a83d15339d64",
+            }
+        },
+        "Linux": {},
+        "Darwin": {},
+        "Windows": {},
+    },
+    "arduino-samd": {
+        "all": {
+            "core": {
+                "version": "1.8.8",
+                "url": "http://downloads.arduino.cc/cores/samd-1.8.8.tar.bz2",
+                "file_name": "samd-1.8.8.tar.bz2",
+                "sha256": "7b93eb705cba9125d9ee52eba09b51fb5fe34520ada351508f4253abbc9f27fa",
+            }
+        },
+        "Linux": {},
+        "Darwin": {},
+        "Windows": {},
+    },
+    "stm32duino": {
+        "all": {
+            "core": {
+                "version": "1.9.0",
+                "url": "https://github.com/stm32duino/Arduino_Core_STM32/archive/1.9.0.tar.gz",
+                "sha256": "4f75ba7a117d90392e8f67c58d31d22393749b9cdd3279bc21e7261ec06c62bf",
+            }
+        },
+        "Linux": {},
+        "Darwin": {},
+        "Windows": {},
+    },
+}
+# yapf: enable
+
+
+def install_core_command(args: argparse.Namespace):
+    install_prefix = os.path.realpath(
+        os.path.expanduser(os.path.expandvars(args.prefix)))
+    install_dir = os.path.join(install_prefix, args.core_name)
+    cache_dir = os.path.join(install_prefix, ".cache", args.core_name)
+
+    if args.core_name in supported_cores():
+        shutil.rmtree(install_dir, ignore_errors=True)
+        os.makedirs(install_dir, exist_ok=True)
+        os.makedirs(cache_dir, exist_ok=True)
+
+    if args.core_name == "teensy":
+        if platform.system() == "Linux":
+            install_teensy_core_linux(install_prefix, install_dir, cache_dir)
+        elif platform.system() == "Darwin":
+            install_teensy_core_mac(install_prefix, install_dir, cache_dir)
+        elif platform.system() == "Windows":
+            install_teensy_core_windows(install_prefix, install_dir, cache_dir)
+    elif args.core_name == "adafruit-samd":
+        install_adafruit_samd_core(install_prefix, install_dir, cache_dir)
+    elif args.core_name == "stm32duino":
+        install_stm32duino_core(install_prefix, install_dir, cache_dir)
+    elif args.core_name == "arduino-samd":
+        install_arduino_samd_core(install_prefix, install_dir, cache_dir)
+    else:
+        _LOG.error("Invalid core '%s'. Supported cores: %s", args.core_name,
+                   ", ".join(supported_cores()))
+        sys.exit(1)
+
+
+def supported_cores():
+    return _ARDUINO_CORE_ARTIFACTS.keys()
+
+
+def install_teensy_core_windows(install_prefix, install_dir, cache_dir):
+    """Download and install Teensyduino artifacts for Windows."""
+    teensy_artifacts = _ARDUINO_CORE_ARTIFACTS["teensy"][platform.system()]
+
+    arduino_artifact = teensy_artifacts["arduino-ide"]
+    arduino_zipfile = file_operations.download_to_cache(
+        url=arduino_artifact["url"],
+        expected_sha256sum=arduino_artifact["sha256"],
+        cache_directory=cache_dir)
+
+    teensyduino_artifact = teensy_artifacts["teensyduino"]
+    teensyduino_installer = file_operations.download_to_cache(
+        url=teensyduino_artifact["url"],
+        expected_sha256sum=teensyduino_artifact["sha256"],
+        cache_directory=cache_dir)
+
+    file_operations.extract_archive(arduino_zipfile, install_dir, cache_dir)
+
+    # "teensy" here should match args.core_name
+    teensy_core_dir = os.path.join(install_prefix, "teensy")
+
+    # Change working directory for installation
+    original_working_dir = os.getcwd()
+    os.chdir(install_prefix)
+
+    _LOG.info("Installing Teensyduino to: %s", teensy_core_dir)
+
+    install_command = [teensyduino_installer, "--dir=teensy"]
+    _LOG.info("  Running: %s", " ".join(install_command))
+    _LOG.info("  Please click yes on the Windows 'User Account Control' "
+              "dialog.")
+    _LOG.info("  You should see: 'Verified publisher: PRJC.COM LLC'")
+
+    install_command = [teensyduino_installer, "--dir=teensy"]
+    subprocess.run(install_command)
+    if not os.path.exists(os.path.join(teensy_core_dir, "hardware", "teensy")):
+        _LOG.error(
+            "Error: Installation Failed.\n"
+            "Please try again and ensure Teensyduino is installed in "
+            "the folder:\n"
+            "%s", teensy_core_dir)
+        sys.exit(1)
+    else:
+        _LOG.info("  Install complete!")
+
+    file_operations.remove_empty_directories(install_dir)
+    os.chdir(original_working_dir)
+
+
+def install_teensy_core_mac(unused_install_prefix, install_dir, cache_dir):
+    """Download and install Teensyduino artifacts for Mac."""
+    teensy_artifacts = _ARDUINO_CORE_ARTIFACTS["teensy"][platform.system()]
+
+    teensyduino_artifact = teensy_artifacts["teensyduino"]
+    teensyduino_zip = file_operations.download_to_cache(
+        url=teensyduino_artifact["url"],
+        expected_sha256sum=teensyduino_artifact["sha256"],
+        cache_directory=cache_dir)
+
+    extracted_files = file_operations.extract_archive(
+        teensyduino_zip,
+        install_dir,
+        cache_dir,
+        remove_single_toplevel_folder=False)
+    toplevel_folder = sorted(extracted_files)[0]
+    os.symlink(os.path.join(toplevel_folder, "Contents", "Java", "hardware"),
+               os.path.join(install_dir, "hardware"),
+               target_is_directory=True)
+
+
+def install_teensy_core_linux(install_prefix, install_dir, cache_dir):
+    """Download and install Teensyduino artifacts for Windows."""
+    teensy_artifacts = _ARDUINO_CORE_ARTIFACTS["teensy"][platform.system()]
+
+    arduino_artifact = teensy_artifacts["arduino-ide"]
+    arduino_tarfile = file_operations.download_to_cache(
+        url=arduino_artifact["url"],
+        expected_sha256sum=arduino_artifact["sha256"],
+        cache_directory=cache_dir)
+
+    teensyduino_artifact = teensy_artifacts["teensyduino"]
+    teensyduino_installer = file_operations.download_to_cache(
+        url=teensyduino_artifact["url"],
+        expected_sha256sum=teensyduino_artifact["sha256"],
+        cache_directory=cache_dir)
+
+    extracted_files = file_operations.extract_archive(arduino_tarfile,
+                                                      install_dir, cache_dir)
+    os.chmod(teensyduino_installer,
+             os.stat(teensyduino_installer).st_mode | stat.S_IEXEC)
+
+    original_working_dir = os.getcwd()
+    os.chdir(install_prefix)
+    # "teensy" here should match args.core_name
+    install_command = [teensyduino_installer, "--dir=teensy"]
+    subprocess.run(install_command)
+
+    # Remove original arduino IDE files
+    for efile in extracted_files:
+        if efile.is_file():
+            efile.unlink()
+
+    file_operations.remove_empty_directories(install_dir)
+    os.chdir(original_working_dir)
+
+
+def install_arduino_samd_core(install_prefix: str, install_dir: str,
+                              cache_dir: str):
+    artifacts = _ARDUINO_CORE_ARTIFACTS["arduino-samd"]["all"]["core"]
+    core_tarfile = file_operations.download_to_cache(
+        url=artifacts["url"],
+        expected_sha256sum=artifacts["sha256"],
+        cache_directory=cache_dir)
+
+    package_path = os.path.join(install_dir, "hardware", "samd",
+                                artifacts["version"])
+    os.makedirs(package_path, exist_ok=True)
+    file_operations.extract_archive(core_tarfile, package_path, cache_dir)
+    original_working_dir = os.getcwd()
+    os.chdir(install_prefix)
+    # TODO(tonymd): Fetch core/tools as specified by:
+    # http://downloads.arduino.cc/packages/package_index.json
+    os.chdir(original_working_dir)
+    return True
+
+
+def install_adafruit_samd_core(install_prefix: str, install_dir: str,
+                               cache_dir: str):
+    artifacts = _ARDUINO_CORE_ARTIFACTS["adafruit-samd"]["all"]["core"]
+    core_tarfile = file_operations.download_to_cache(
+        url=artifacts["url"],
+        expected_sha256sum=artifacts["sha256"],
+        cache_directory=cache_dir)
+
+    package_path = os.path.join(install_dir, "hardware", "samd",
+                                artifacts["version"])
+    os.makedirs(package_path, exist_ok=True)
+    file_operations.extract_archive(core_tarfile, package_path, cache_dir)
+
+    original_working_dir = os.getcwd()
+    os.chdir(install_prefix)
+    # TODO(tonymd): Fetch platform specific tools as specified by:
+    # https://adafruit.github.io/arduino-board-index/package_adafruit_index.json
+    # Specifically:
+    #   https://github.com/ARM-software/CMSIS_5/archive/5.4.0.tar.gz
+    os.chdir(original_working_dir)
+    return True
+
+
+def install_stm32duino_core(install_prefix, install_dir, cache_dir):
+    artifacts = _ARDUINO_CORE_ARTIFACTS["stm32duino"]["all"]["core"]
+    core_tarfile = file_operations.download_to_cache(
+        url=artifacts["url"],
+        expected_sha256sum=artifacts["sha256"],
+        cache_directory=cache_dir)
+
+    package_path = os.path.join(install_dir, "hardware", "stm32",
+                                artifacts["version"])
+    os.makedirs(package_path, exist_ok=True)
+    file_operations.extract_archive(core_tarfile, package_path, cache_dir)
+    original_working_dir = os.getcwd()
+    os.chdir(install_prefix)
+    # TODO(tonymd): Fetch platform specific tools as specified by:
+    # https://github.com/stm32duino/BoardManagerFiles/raw/master/STM32/package_stm_index.json
+    os.chdir(original_working_dir)
+    return True
diff --git a/pw_arduino_build/py/pw_arduino_build/file_operations.py b/pw_arduino_build/py/pw_arduino_build/file_operations.py
new file mode 100644
index 000000000..2bcdb69ca
--- /dev/null
+++ b/pw_arduino_build/py/pw_arduino_build/file_operations.py
@@ -0,0 +1,190 @@
+#!/usr/bin/env python3
+# Copyright 2020 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+"""File Helper Functions."""
+
+import glob
+import hashlib
+import logging
+import os
+import shutil
+import sys
+import tarfile
+import urllib.request
+import zipfile
+from pathlib import Path
+from typing import List
+
+_LOG = logging.getLogger(__name__)
+
+
+class InvalidChecksumError(Exception):
+    pass
+
+
+def find_files(starting_dir: str,
+               patterns: List[str],
+               directories_only=False) -> List[str]:
+    original_working_dir = os.getcwd()
+    if not (os.path.exists(starting_dir) and os.path.isdir(starting_dir)):
+        _LOG.error("Directory '%s' does not exist.", starting_dir)
+        raise FileNotFoundError
+
+    os.chdir(starting_dir)
+    files = []
+    for pattern in patterns:
+        for file_path in glob.glob(pattern, recursive=True):
+            if not directories_only or (directories_only
+                                        and os.path.isdir(file_path)):
+                files.append(file_path)
+    os.chdir(original_working_dir)
+    return sorted(files)
+
+
+def sha256_sum(file_name):
+    hash_sha256 = hashlib.sha256()
+    with open(file_name, "rb") as file_handle:
+        for chunk in iter(lambda: file_handle.read(4096), b""):
+            hash_sha256.update(chunk)
+    return hash_sha256.hexdigest()
+
+
+def md5_sum(file_name):
+    hash_md5 = hashlib.md5()
+    with open(file_name, "rb") as file_handle:
+        for chunk in iter(lambda: file_handle.read(4096), b""):
+            hash_md5.update(chunk)
+    return hash_md5.hexdigest()
+
+
+def verify_file_checksum(file_path,
+                         expected_checksum,
+                         sum_function=sha256_sum):
+    downloaded_checksum = sum_function(file_path)
+    try:
+        if downloaded_checksum != expected_checksum:
+            raise InvalidChecksumError
+    except InvalidChecksumError:
+        _LOG.exception("Invalid %s\n"
+                       "%s %s\n"
+                       "%s (expected)",
+                       sum_function.__name__, downloaded_checksum,
+                       os.path.basename(file_path), expected_checksum)
+        # Exit to stop installation
+        return sys.exit(1)
+
+    _LOG.info("  %s:", sum_function.__name__)
+    _LOG.info("  %s %s", downloaded_checksum, os.path.basename(file_path))
+    return True
+
+
+def download_to_cache(url: str,
+                      expected_md5sum=None,
+                      expected_sha256sum=None,
+                      cache_directory=".cache") -> str:
+
+    cache_dir = os.path.realpath(
+        os.path.expanduser(os.path.expandvars(cache_directory)))
+    downloaded_file = os.path.join(cache_dir, url.split("/")[-1])
+
+    if not os.path.exists(downloaded_file):
+        _LOG.info("Downloading: %s", url)
+        urllib.request.urlretrieve(url, filename=downloaded_file)
+
+    if os.path.exists(downloaded_file):
+        _LOG.info("Downloaded: %s", downloaded_file)
+        if expected_sha256sum:
+            verify_file_checksum(downloaded_file,
+                                 expected_sha256sum,
+                                 sum_function=sha256_sum)
+        elif expected_md5sum:
+            verify_file_checksum(downloaded_file,
+                                 expected_md5sum,
+                                 sum_function=md5_sum)
+
+    return downloaded_file
+
+
+def extract_zipfile(archive_file: str, dest_dir: str):
+    with zipfile.ZipFile(archive_file) as archive:
+        archive.extractall(path=dest_dir)
+
+
+def extract_tarfile(archive_file: str, dest_dir: str):
+    with tarfile.open(archive_file, 'r') as archive:
+        archive.extractall(path=dest_dir)
+
+
+def extract_archive(archive_file: str,
+                    dest_dir: str,
+                    cache_dir: str,
+                    remove_single_toplevel_folder=True):
+    """Extract a tar or zip file.
+
+    Args:
+        archive_file (str): Absolute path to the archive file.
+        dest_dir (str): Extraction destination directory.
+        cache_dir (str): Directory where temp files can be created.
+        remove_single_toplevel_folder (bool): If the archive contains only a
+            single folder move the contents of that into the destination
+            directory.
+    """
+    # Make a temporary directory to extract files into
+    temp_extract_dir = os.path.join(cache_dir,
+                                    "." + os.path.basename(archive_file))
+    os.makedirs(temp_extract_dir, exist_ok=True)
+
+    _LOG.info("Extracting: %s", archive_file)
+    if zipfile.is_zipfile(archive_file):
+        extract_zipfile(archive_file, temp_extract_dir)
+    elif tarfile.is_tarfile(archive_file):
+        extract_tarfile(archive_file, temp_extract_dir)
+    else:
+        _LOG.error("Unknown archive format: %s", archive_file)
+        return sys.exit(1)
+
+    _LOG.info("Installing into: %s", dest_dir)
+    path_to_extracted_files = temp_extract_dir
+
+    extracted_top_level_files = os.listdir(temp_extract_dir)
+    # Check if tarfile has only one folder
+    # If yes, make that the new path_to_extracted_files
+    if remove_single_toplevel_folder and len(extracted_top_level_files) == 1:
+        path_to_extracted_files = os.path.join(temp_extract_dir,
+                                               extracted_top_level_files[0])
+
+    # Move extracted files to dest_dir
+    extracted_files = os.listdir(path_to_extracted_files)
+    for file_name in extracted_files:
+        source_file = os.path.join(path_to_extracted_files, file_name)
+        dest_file = os.path.join(dest_dir, file_name)
+        shutil.move(source_file, dest_file)
+
+    # rm -rf temp_extract_dir
+    shutil.rmtree(temp_extract_dir, ignore_errors=True)
+
+    # Return List of extracted files
+    return list(Path(dest_dir).rglob("*"))
+
+
+def remove_empty_directories(directory):
+    """Recursively remove empty directories."""
+
+    for path in sorted(Path(directory).rglob("*"), reverse=True):
+        # If broken symlink
+        if path.is_symlink() and not path.exists():
+            path.unlink()
+        # if empty directory
+        elif path.is_dir() and len(os.listdir(path)) == 0:
+            path.rmdir()
diff --git a/pw_arduino_build/py/pw_arduino_build/log.py b/pw_arduino_build/py/pw_arduino_build/log.py
new file mode 100644
index 000000000..d5ed9f795
--- /dev/null
+++ b/pw_arduino_build/py/pw_arduino_build/log.py
@@ -0,0 +1,39 @@
+# Copyright 2020 The Pigweed Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License"); you may not
+# use this file except in compliance with the License. You may obtain a copy of
+# the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations under
+# the License.
+"""Configure the system logger for the default pw command log format."""
+
+import logging
+
+_LOG = logging.getLogger(__name__)
+_STDERR_HANDLER = logging.StreamHandler()
+
+
+def install(level: int = logging.INFO) -> None:
+    """Configure the system logger for the arduino_builder log format."""
+
+    # Set log level on root logger to debug, otherwise any higher levels
+    # elsewhere are ignored.
+    root = logging.getLogger()
+    root.setLevel(logging.DEBUG)
+
+    _STDERR_HANDLER.setLevel(level)
+    _STDERR_HANDLER.setFormatter(
+        logging.Formatter("[%(asctime)s] "
+                          "%(levelname)s %(message)s", "%Y%m%d %H:%M:%S"))
+    root.addHandler(_STDERR_HANDLER)
+
+
+def set_level(log_level: int):
+    """Sets the log level for logs to stderr."""
+    _STDERR_HANDLER.setLevel(log_level)
diff --git a/pw_arduino_build/py/setup.py b/pw_arduino_build/py/setup.py
index 5c472957b..1cb074f75 100644
--- a/pw_arduino_build/py/setup.py
+++ b/pw_arduino_build/py/setup.py
@@ -24,8 +24,7 @@ setuptools.setup(
     packages=setuptools.find_packages(),
     entry_points={
         'console_scripts':
-        ['arduino_builder = '
-         '    pw_arduino_build.arduinobuilder:main']
+        ['arduino_builder = pw_arduino_build.__main__:main']
     },
     install_requires=[
         'pyserial',