Add N, N-1, and main branch release drafting

Updates the `ReleaseDrafter.yml` workflow to filter the base ref to
use when composing the release draft based on the GitHub trigger
context. This allows simultaneous release drafting in repos that
use release branches while repos with non-release branches (e.g.
main branch) are not impacted.

Adds a variable to `Version.njk` to track the previous Mu release
branch name. This files continues to serve as a single location
where the release branches are defined.

Updates the file sync process to sync the release drafter config
file as needed for the corresponding repo.

Signed-off-by: Michael Kubacki <michael.kubacki@microsoft.com>

Author: makubacki

.github/workflows/ReleaseDrafter.yml

@@ -6,6 +6,24 @@
 # the code is constantly maintained based on Project Mu label conventions to ensure
 # semantic versioning is followed and a release version is always ready.
 #
+# The workflow is set up to support three types of repos as used in Project Mu. The
+# config file name varies depending on the branch being built.
+#
+#   1. A "latest release branch"
+#      - Example: `release/202302`
+#      - Config file: `release-draft-config-n.yml`
+#   2. A "previous release branch"
+#      - Example: `release/202208`
+#      - Config file: `release-draft-config-n-1.yml`
+#   3. A "main branch"
+#      - Example: `main`
+#      - Config file: `release-draft-config.yml`
+#
+# Note:
+#   - The versions for the above types of repos are automatically read from .sync/Version.njk.
+#   - The correct config files are automatically synced to the corresponding branches by the
+#     Mu DevOps file sync operation. No manual maintenance is needed.
+#
 # Project Mu repos are encouraged to use this reusable workflow if this release
 # workflow makes sense in their repo.
 #
@@ -29,8 +47,51 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
+      - name: Download Version Information
+        if: ${{ startsWith(github.ref, 'refs/heads/release') }}
+        id: download_ver_info
+        shell: bash
+        run: |
+          mkdir $HOME/temp
+          versionFileUrl="https://raw.githubusercontent.com/microsoft/mu_devops/main/.sync/Version.njk"
+          localFilePath=$HOME/temp/Version.njk
+          curl $versionFileUrl --output "${localFilePath}"
+          echo "file_path=${localFilePath}" >> $GITHUB_ENV
+      - name: Extract Version Information
+        if: ${{ startsWith(github.ref, 'refs/heads/release') }}
+        id: extract_ver_info
+        shell: bash
+        env:
+          FILE_PATH: ${{ env.file_path }}
+        run: |
+          fileContent=$(cat "${FILE_PATH}")
+          latestMuReleaseBranch=$(echo "$fileContent" | grep -oP '(?<=latest_mu_release_branch = ").*(?=")')
+          previousMuReleaseBranch=$(echo "$fileContent" | grep -oP '(?<=previous_mu_release_branch = ").*(?=")')
+          echo "latest_mu_branch=${latestMuReleaseBranch}" >> $GITHUB_ENV
+          echo "latest_mu_branch_full=refs/heads/${latestMuReleaseBranch}" >> $GITHUB_ENV
+          echo "previous_mu_branch=${previousMuReleaseBranch}" >> $GITHUB_ENV
+          echo "previous_mu_branch_full=refs/heads/${previousMuReleaseBranch}" >> $GITHUB_ENV
+      - name: Build a ${{ env.latest_mu_branch }} Draft
+        if: ${{ startsWith(github.ref, env.latest_mu_branch_full) }}
+        id: update_draft_n
+        uses: release-drafter/release-drafter@v5.23.0
+        with:
+          # Note: Path is relative to .github/
+          config-name: release-draft-config-n.yml
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      - name: Build a ${{ env.previous_mu_branch }} Draft
+        if: ${{ startsWith(github.ref, env.previous_mu_branch_full) }}
+        id: update_draft_n_1
+        uses: release-drafter/release-drafter@v5.23.0
+        with:
+          # Note: Path is relative to .github/
+          config-name: release-draft-config-n-1.yml
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
       - name: Build the New Release Draft
-        id: update_draft
+        if: ${{ !startsWith(github.ref, 'refs/heads/release') }}
+        id: update_draft_non_release
         uses: release-drafter/release-drafter@v5.23.0
         with:
           # Note: Path is relative to .github/

.sync/Files.yml

@@ -441,6 +441,7 @@ group:
         trigger_branch_name: 'main'
     - source: .sync/workflows/config/release-draft/release-draft-config.yml
       dest: .github/release-draft-config.yml
+      template: true
     repos: |
       microsoft/mu_devops
       microsoft/mu_feature_config
@@ -451,14 +452,22 @@ group:
       microsoft/mu_tiano_platforms
 
 # Leaf Workflow - Release Draft
-# Note: The default branch name used to draft releases on in this group is
-#       the latest Mu release branch (e.g. "release/202302")
+# Note: This group has two files synced that allow separate configuration for
+#       n (e.g. "release/202302") and n-1 (e.g. "release/202208") branches.
   - files:
     - source: .sync/workflows/leaf/release-draft.yml
       dest: .github/workflows/release-draft.yml
       template: true
     - source: .sync/workflows/config/release-draft/release-draft-config.yml
-      dest: .github/release-draft-config.yml
+      dest: .github/release-draft-config-n.yml
+      template:
+        latest: true
+        release_branch: true
+    - source: .sync/workflows/config/release-draft/release-draft-config.yml
+      dest: .github/release-draft-config-n-1.yml
+      template:
+        latest: false
+        release_branch: true
     repos: |
       microsoft/mu_basecore
       microsoft/mu_common_intel_min_platform

.sync/Version.njk

@@ -34,6 +34,7 @@
 
 {# The latest Project Mu release branch value. #}
 {% set latest_mu_release_branch = "release/202302" %}
+{% set previous_mu_release_branch = "release/202208" %}
 
 {# The version of the ubuntu-22-build container to use. #}
 {% set linux_build_container = "ghcr.io/microsoft/mu_devops/ubuntu-22-build:bc713a5" %}

.sync/workflows/config/release-draft/release-draft-config.yml

@@ -17,9 +17,19 @@
 # For more information, see:
 # https://github.com/release-drafter/release-drafter
 
+{% import '../../../Version.njk' as sync_version -%}
+
 name-template: 'v$RESOLVED_VERSION'
 tag-template: 'v$RESOLVED_VERSION'
 
+{# `release_branch` applies a commitish. `latest` then determines the branch to use. -#}
+{# If a commitish is not specified, then the `github.ref` value is implicitly used. -#}
+{%- if release_branch %}
+{% set release_branch = "refs/heads/" + (sync_version.latest_mu_release_branch if latest else sync_version.previous_mu_release_branch) %}
+commitish: {{ release_branch }}
+filter-by-commitish: true
+{% endif %}
+
 template: |
   # What's Changed