DNL: Add example of using expand_template to stamp a pacakge.json for use in an npm_package

expand_template/.aspect/bazelrc/.gitignore

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+user.bazelrc

expand_template/.aspect/bazelrc/ci.bazelrc

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+../../../bazelrc/.aspect/bazelrc/ci.bazelrc

expand_template/.aspect/bazelrc/common.bazelrc

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+../../../bazelrc/.aspect/bazelrc/common.bazelrc

expand_template/.aspect/bazelrc/common6.bazelrc

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+../../../bazelrc/.aspect/bazelrc/common6.bazelrc

expand_template/.aspect/bazelrc/javascript.bazelrc

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+../../../bazelrc/.aspect/bazelrc/javascript.bazelrc

expand_template/.bazeliskrc

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+../bazelrc/.bazeliskrc

expand_template/.bazelrc

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+# Import Aspect recommended Bazel settings for all projects
+import %workspace%/.aspect/bazelrc/common.bazelrc
+
+# Import Aspect recommended Bazel 6 only settings for all projects
+import %workspace%/.aspect/bazelrc/common6.bazelrc
+
+# Import Aspect recommended Bazel settings for JavaScript projects
+import %workspace%/.aspect/bazelrc/javascript.bazelrc
+
+common --enable_bzlmod
+
+# TODO: something is up with expand_template in the sandbox in this simple example
+build --spawn_strategy=local
+build --stamp
+build --workspace_status_command "${PWD}/workspace_status.sh"
+
+# Load any settings & overrides specific to the current user from `.aspect/bazelrc/user.bazelrc`.
+# This file should appear in `.gitignore` so that settings are not shared with team members. This
+# should be last statement in this config so the user configuration is able to overwrite flags from
+# this file. See https://bazel.build/configure/best-practices#bazelrc-file.
+try-import %workspace%/.aspect/bazelrc/user.bazelrc

expand_template/.bazelversion

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+../bazelrc/.bazelversion

expand_template/.gitignore

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+/bazel-*

expand_template/BUILD.bazel

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+# We can't use the bazel-lib one, because it doesn't have a program to read stamp vars.
+# see https://github.com/aspect-build/rules_js/pull/384#issue-1337742941
+# buildifier: disable=bzl-visibility
+load("@aspect_rules_js//js/private:expand_template.bzl", "expand_template")
+load("@aspect_rules_js//npm:defs.bzl", "npm_package")
+load("@bazel_skylib//rules:build_test.bzl", "build_test")
+
+expand_template(
+    name = "stamped_package_json",
+    out = "stamped_package.json",
+    stamp = 1,
+    substitutions = {
+        "{{VERSION}}": "{{STABLE_BUILD_SCM_TAG}}",
+    },
+    template = "package.json",
+)
+
+npm_package(
+    name = "package",
+    srcs = [
+        "index.js",
+        ":stamped_package_json",
+    ],
+    replace_prefixes = {
+        "stamped_package.json": "package.json",
+    },
+)
+
+build_test(
+    name = "build_test",
+    targets = [":package"],
+)

expand_template/MODULE.bazel

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+bazel_dep(name = "aspect_rules_js", version = "1.16.0")
+bazel_dep(name = "bazel_skylib",     version = "1.3.0")

expand_template/index.js

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+module.exports = 1;

expand_template/package.json

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+{
+  "version": "{{VERSION}}"
+}

expand_template/workspace_status.sh

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+#!/bin/bash
+# This script is called by Bazel when it needs info about the git state.
+# The --workspace_status_command flag tells Bazel the location of this script.
+# This is configured in `/.bazelrc`.
+set -o pipefail -o errexit -o nounset
+
+function has_local_changes {
+    if [ "$(git status --porcelain)" != "" ]; then
+        echo dirty
+    else
+        echo clean
+    fi
+}
+
+# "volatile" keys, these will not cause a re-build because they're assumed to change on every build
+# and its okay to use a stale value in a stamped binary
+echo "BUILD_TIME $(date "+%Y-%m-%d %H:%M:%S %Z")"
+
+# "stable" keys, should remain constant over rebuilds, therefore changed values will cause a
+# rebuild of any stamped action that uses ctx.info_file or genrule with stamp = True
+# Note, BUILD_USER is automatically available in the stable-status.txt, it matches $USER
+echo "STABLE_BUILD_SCM_SHA $(git rev-parse HEAD)"
+echo "STABLE_BUILD_SCM_LOCAL_CHANGES $(has_local_changes)"
+
+# For demonstration, STABLE_BUILD_SCM_TAG is hard-coded to 1.2.3. Typically you would set this to
+# the output of `git describe --tags` or use a program such as https://github.com/choffmeister/git-describe-semver
+# to produce a semver compliant version. Alex's blog post, https://blog.aspect.dev/versioning-releases-from-a-monorepo,
+# describes an alternative monorepo versioning scheme.
+echo "STABLE_BUILD_SCM_TAG 1.2.3"