Make template_rule.bzl local to each workspace that use it.

PiperOrigin-RevId: 442755202

1 files changed, 58 insertions, 0 deletions

diff --git a/java_src/template_rule.bzl b/java_src/template_rule.bzl
new file mode 100644
index 000000000..badceb97c
--- /dev/null
+++ b/java_src/template_rule.bzl
@@ -0,0 +1,58 @@
+# Copyright 2022 Google LLC
+#
+# 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
+#
+# http://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.
+
+"""Rule for simple expansion of template files."""
+
+def _template_rule_impl(ctx):
+    """Modifies ctx.file.src keys in ctx.attr.substitutions with corresponding values."""
+    ctx.actions.expand_template(
+        template = ctx.file.src,
+        output = ctx.outputs.out,
+        substitutions = ctx.attr.substitutions,
+    )
+
+# Rule for simple expansion of template files. Modifies the templates in src substituting the keys
+# in substitutions with the corresponding values; the result is output to out.
+#
+# Borrowed from TensorFlow (https://github.com/tensorflow/tensorflow)
+#
+# Typical usage:
+#   template_rule(
+#       name = "ExpandMyTemplate",
+#       src = "my.template",
+#       out = "my.txt",
+#       substitutions = {
+#         "$VAR1": "foo",
+#         "$VAR2": "bar",
+#       }
+#   )
+#
+# Args:
+#   name: The name of the rule.
+#   src: The template file to expand
+#   out: The destination of the expanded file
+#   substitutions: A dictionary mapping strings to their substitutions
+template_rule = rule(
+    attrs = {
+        "src": attr.label(
+            mandatory = True,
+            allow_single_file = True,
+        ),
+        "substitutions": attr.string_dict(mandatory = True),
+        "out": attr.output(mandatory = True),
+    },
+    # output_to_genfiles is required for header files.
+    output_to_genfiles = True,
+    implementation = _template_rule_impl,
+)