1 files changed, 90 insertions, 0 deletions
diff --git a/examples/policy_checker/license_policy_check.bzl b/examples/policy_checker/license_policy_check.bzl
new file mode 100644
index 0000000..bb35eee
--- /dev/null
+++ b/examples/policy_checker/license_policy_check.bzl
@@ -0,0 +1,90 @@
+# Copyright 2020 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
+#
+# 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.
+
+"""License compliance checking at analysis time."""
+
+load(
+    "@rules_license//examples/policy_checker:license_policy_provider.bzl",
+    "LicensePolicyInfo",
+)
+load(
+    "@rules_license//rules:gather_licenses_info.bzl",
+    "gather_licenses_info",
+)
+load("@rules_license//rules:providers.bzl", "LicenseInfo")
+load("@rules_license//rules/private:gathering_providers.bzl", "TransitiveLicensesInfo")
+
+# This is a crude example of the kind of thing which can be done.
+def _license_policy_check_impl(ctx):
+    policy = ctx.attr.policy[LicensePolicyInfo]
+    allowed_conditions = policy.conditions
+    if TransitiveLicensesInfo in ctx.attr.target:
+        for license in ctx.attr.target[TransitiveLicensesInfo].licenses.to_list():
+            for kind in license.license_kinds:
+                # print(kind.conditions)
+                for condition in kind.conditions:
+                    if condition not in allowed_conditions:
+                        fail("Condition %s violates policy %s" % (
+                            condition,
+                            policy.label,
+                        ))
+
+    if LicenseInfo in ctx.attr.target:
+        for license in ctx.attr.target[LicenseInfo].licenses.to_list():
+            for kind in license.license_kinds:
+                # print(kind.conditions)
+                for condition in kind.conditions:
+                    if condition not in allowed_conditions:
+                        fail("Condition %s violates policy %s" % (
+                            condition,
+                            policy.label,
+                        ))
+    return [DefaultInfo()]
+
+_license_policy_check = rule(
+    implementation = _license_policy_check_impl,
+    doc = """Internal implementation method for license_policy_check().""",
+    attrs = {
+        "policy": attr.label(
+            doc = """Policy definition.""",
+            mandatory = True,
+            providers = [LicensePolicyInfo],
+        ),
+        "target": attr.label(
+            doc = """Target to collect LicenseInfo for.""",
+            aspects = [gather_licenses_info],
+            mandatory = True,
+            allow_single_file = True,
+        ),
+    },
+)
+
+def license_policy_check(name, target, policy, **kwargs):
+    """Checks a target against a policy.
+
+    Args:
+      name: The target.
+      target: A target to test for compliance with a policy
+      policy: A rule providing LicensePolicyInfo.
+      **kwargs: other args.
+
+    Usage:
+
+      license_policy_check(
+          name = "license_info",
+          target = ":my_app",
+          policy = "//my_org/compliance/policies:mobile_application",
+      )
+    """
+    _license_policy_check(name = name, target = target, policy = policy, **kwargs)