build: upload release packages as job artifacts for PRs

Upload release packages as job artifacts for PRs. This allows
us to easily check out changes from a PR locally, without having
to manually check-out the branch, and building the release output.

Co-authored-by: George Kalpakas <kalpakas.g@gmail.com>

.circleci/config.yml

@@ -132,6 +132,12 @@ var_19: &skip_on_pull_requests_filter
       ignore:
         - /pull\/\d+/
 
+# Filter which ensures that jobs only run for pull requests.
+var_20: &only_on_pull_requests_filter
+  branches:
+      only:
+        - /pull\/\d+/
+
 # -----------------------------
 # Container version of CircleCI
 # -----------------------------
@@ -342,6 +348,21 @@ jobs:
           path: /tmp/cdk-umd-minified-bundles
           destination: /angular_material/cdk_release_output/
 
+  upload_release_packages:
+    <<: *job_defaults
+    steps:
+      - *checkout_code
+      - *restore_cache
+      - *attach_release_output
+      - *yarn_install
+
+      # Creates package archives and passes in an appropriate meaningful archive suffix. The
+      # suffix consists of the pull request number and a short SHA describing the current `HEAD`.
+      - run: ./scripts/create-package-archives.js --suffix "$CIRCLE_PR_NUMBER-$(git rev-parse --short HEAD)"
+      # Upload archives to the CircleCI job artifacts.
+      - store_artifacts:
+          path: dist/release-archives
+
   # ----------------------------------------
   # Job that publishes the build snapshots
   # ----------------------------------------
@@ -514,6 +535,12 @@ workflows:
           filters: *ignore_presubmit_branch_filter
       - build_release_packages:
           filters: *ignore_presubmit_branch_filter
+      - upload_release_packages:
+          # We don't want to run this job on push builds because for those, the
+          # `publish_snapshots` runs, and publishes build artifacts.
+          filters: *only_on_pull_requests_filter
+          requires:
+            - build_release_packages
       - lint:
           filters: *ignore_presubmit_branch_filter
       - ngcc_compatibility:

DEV_ENVIRONMENT.md

@@ -23,3 +23,38 @@ and rebuild. The browser should refresh automatically when changes are made.
 To run unit tests, run `yarn test <target>`. The `target` can be either a short name (e.g. `yarn test button`) or an explicit path `yarn test src/cdk/stepper`.
 To run the e2e tests, run `yarn e2e`.
 To run lint, run `yarn lint`.
+
+### Getting Packages from Build Artifacts
+Each CI run for a Pull Request stores the built Angular packages as
+[build artifacts](https://circleci.com/docs/2.0/artifacts). The artifacts are not guaranteed to be
+available as a long-term distribution mechanism, but they are guaranteed to be available around the
+time of the build.
+
+You can access the artifacts for a specific CI run by going to the workflow page, clicking on the
+`upload_release_packages` job and then switching to the "Artifacts" tab.
+
+#### Archives for each Package
+On the "Artifacts" tab, there is a list of links to compressed archives for Angular packages. The
+archive names are of the format `<package-name>-pr<pr-number>-<sha>.tgz` (for example
+`material-pr12345-a1b2c3d.tgz`).
+
+One can use the URL to the `.tgz` file for each package to install them as dependencies in a
+project they need to test the Pull Request changes against. [Yarn](https://yarnpkg.com/lang/en/docs/cli/add)
+supports installing dependencies from URLs to `.tgz` files. As an example, update the dependencies
+in `package.json` to point to the artifact URLs and then run `yarn` to install the packages:
+
+```json
+"dependencies": {
+  "@angular/cdk": "https://<...>.circle-artifacts.com<...>/cdk-pr12345-a1b2c3d.tgz",
+  "@angular/material": "https://<...>.circle-artifacts.com<...>/material-pr12345-a1b2c3d.tgz",
+}
+```
+
+#### Download all Packages
+In addition to the individual package archives, a `.tgz` file including all packages is also
+available (named `all-pr<pr-number>-<sha>.tgz`). This can be used if one prefers to download all
+packages locally and test them by either of the following ways:
+
+1. Update the dependencies in `package.json` to point to the local uncompressed package directories.
+2. Directly copy the local uncompressed package directories into the `node_modules/` directory
+   of a project.

scripts/create-package-archives.js

@@ -0,0 +1,56 @@
+#!/usr/bin/env node
+
+/**
+ * Script that creates tar archives of built release packages. These archives can then
+ * be uploaded to the CircleCI artifacts so that PRs or individual commits can be easily
+ * tested out without having to build the release packages manually, and packing them up.
+ *
+ * This is different to the snapshot builds repositories as those only are available for
+ * the primary `cdk` and `material` packages, and also don't run for pull requests.
+ */
+
+const {join} = require('path');
+const {rm, mkdir, test, ls, set, exec, cd} = require('shelljs');
+const {red, green} = require('chalk');
+const minimist = require('minimist');
+
+const projectDir = join(__dirname, '../');
+const archivesDir = 'dist/release-archives';
+const releasesDir = 'dist/releases';
+let {suffix} = minimist(process.argv.slice(2), {string: ['suffix']});
+
+if (!suffix) {
+  console.error(red('No suffix specified. Pass one with --suffix <text>'));
+  process.exit(1);
+}
+
+// Fail if any ShellJS command fails.
+set('-e');
+
+cd(projectDir);
+
+if (!test('-e', releasesDir)) {
+  console.error(red('The release output has not been built.'));
+  process.exit(1);
+}
+
+rm('-Rf', archivesDir);
+mkdir('-p', archivesDir);
+
+const builtPackages = ls(releasesDir)
+  .map(name => ({name, path: join(releasesDir, name)}))
+  .filter(pkg => test('-d', pkg.path));
+
+// If multiple packages should be archived, we also generate a single archive that
+// contains all packages. This makes it easier to transfer the release packages.
+if (builtPackages.length > 1) {
+  console.info('Creating archive with all packages..');
+  exec(`tar --create --gzip --directory ${releasesDir} --file ${archivesDir}/all-${suffix}.tgz .`);
+}
+
+for (const pkg of builtPackages) {
+  console.info(`Creating archive for package: ${pkg.name}`);
+  exec(`tar --create --gzip --directory ${pkg.path} --file ${archivesDir}/${pkg.name}-${suffix}.tgz .`);
+}
+
+console.info(green(`Created package archives in: ${archivesDir}`));