ci: Add sync workflow (#626)

Signed-off-by: Ryan Northey <ryan@synca.io>

.github/workflows/mirror.yml

@@ -0,0 +1,38 @@
+name: Sync Envoy
+
+on:
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}
+  cancel-in-progress: true
+
+permissions:
+  contents: read
+
+jobs:
+  sync:
+    runs-on: ubuntu-20.04
+    permissions:
+      contents: write
+    if: |
+      ${{
+          !contains(github.actor, '[bot]')
+          || github.actor == 'sync-envoy[bot]'
+      }}
+    steps:
+    # Checkout the repo at provided commit
+    - name: 'Checkout Repository'
+      uses: actions/checkout@v3
+
+    # Checkout the Envoy repo at latest commit
+    - name: 'Checkout Repository'
+      uses: actions/checkout@v3
+      with:
+        repository: envoyproxy/envoy
+        fetch-depth: 0
+        path: upstream
+
+    - run: mv upstream ../envoy
+    - run: ci/mirror.sh
+      working-directory: ../envoy

ci/mirror.sh

@@ -0,0 +1,39 @@
+#!/bin/bash
+
+set -e
+
+CHECKOUT_DIR=../data-plane-api
+API_MAIN_BRANCH="main"
+
+# Determine last envoyproxy/envoy SHA in envoyproxy/data-plane-api
+MIRROR_MSG="Mirrored from https://github.com/envoyproxy/envoy"
+LAST_ENVOY_SHA=$(git -C "$CHECKOUT_DIR" log --grep="$MIRROR_MSG" -n 1 | grep "$MIRROR_MSG" | \
+  tail -n 1 | sed -e "s#.*$MIRROR_MSG @ ##")
+
+echo "Last mirrored envoyproxy/envoy SHA is $LAST_ENVOY_SHA"
+
+# Compute SHA sequence to replay in envoyproxy/data-plane-api
+SHAS=$(git rev-list --reverse "$LAST_ENVOY_SHA"..HEAD api/)
+
+# For each SHA, hard reset, rsync api/ and generate commit in
+# envoyproxy/data-plane-api
+API_WORKING_DIR="../envoy-api-mirror"
+git worktree add "$API_WORKING_DIR"
+for sha in $SHAS; do
+    echo "Adding commit ${sha}"
+    git -C "$API_WORKING_DIR" reset --hard "$sha"
+    COMMIT_MSG=$(git -C "$API_WORKING_DIR" log --format=%B -n 1)
+    QUALIFIED_COMMIT_MSG=$(echo -e "$COMMIT_MSG\n\n$MIRROR_MSG @ $sha")
+    rsync -acv --delete --exclude "ci/" --exclude ".*" --exclude LICENSE \
+          "$API_WORKING_DIR"/api/ "$CHECKOUT_DIR"/
+    git -C "$CHECKOUT_DIR" add .
+    git -C "$CHECKOUT_DIR" commit -m "$QUALIFIED_COMMIT_MSG"
+done
+
+if [[ -n "$SHAS" ]]; then
+    echo "Pushing..."
+    git -C "$CHECKOUT_DIR" push origin "${API_MAIN_BRANCH}"
+else
+    echo "Nothing to push"
+fi
+echo "Done"