Fix coverage metadata commit info (#1323)

.buildkite/scripts/gen_coverage_metadata.sh

@@ -9,9 +9,23 @@ set -ex
 #   commit-sha: 6953daa563e8e44512bc349c9608484cfd4ec4ff
 #   timestamp: 2024-03-04T19:29:16Z
 
+# Required env variables:
+# - BUILDKITE_BRANCH
+# - BUILDKITE_COMMIT
+
 output_path="$1"
 
-echo "commit-sha: $(git rev-parse HEAD)" > "$output_path"
+if [ "$BUILDKITE_BRANCH" != "master" ] && [ "$BUILDKITE_BRANCH" != "origin/master" ]; then
+  echo "Coverage metadata is only generated for master branch. Current branch: $BUILDKITE_BRANCH"
+  exit 0
+fi
+
+if [ -z "$BUILDKITE_COMMIT" ]; then
+  echo "BUILDKITE_COMMIT is not set"
+  exit 1
+fi
+
+echo "commit-sha: $BUILDKITE_COMMIT" > "$output_path"
 echo "timestamp: $(date -u +%Y-%m-%dT%H:%M:%SZ)" >> "$output_path"
 
 echo "Coverage metadata written to $output_path"

docker/buildkite/docker-compose.yml

@@ -81,6 +81,8 @@ services:
       dockerfile: ./docker/buildkite/Dockerfile
     environment:
       - "GO111MODULE=on"
+      - BUILDKITE_BRANCH
+      - BUILDKITE_COMMIT
     volumes:
       - ../../:/go/src/go.uber.org/cadence
     networks: