Add metadata logging when the build fails (#630)

* Add metadata logging when the build fails

bin/compile

@@ -70,6 +70,7 @@ handle_failure() {
   echo "       Read more: https://devcenter.heroku.com/changelog-items/1573"
   echo ""
 
+  meta_set "node-build-success" "false"
   header "Build failed"
   fail_yarn_outdated "$LOG_FILE"
   fail_yarn_lockfile_outdated "$LOG_FILE"
@@ -81,6 +82,7 @@ handle_failure() {
   warn_angular_resolution "$LOG_FILE"
   warn_missing_devdeps "$LOG_FILE" "$BUILD_DIR"
   warn_econnreset "$LOG_FILE"
+  log_meta_data >> "$BUILDPACK_LOG_FILE"
   failure_message | output "$LOG_FILE"
 }
 trap 'handle_failure' ERR

lib/builddata.sh

 #!/usr/bin/env bash
 
 log_initial_state() {
+  meta_set "buildpack" "nodejs"
   if "$YARN"; then
     meta_set "node-package-manager" "yarn"
     meta_set "has-node-lock-file" "true"

test/run

@@ -1043,11 +1043,9 @@ testMemoryMetrics() {
 }
 
 testBuildMetaData() {
-  env_dir=$(mktmpdir)
   local log_file=$(mktemp)
-  echo "$log_file" > $env_dir/BUILDPACK_LOG_FILE
 
-  compile "pre-post-build-scripts" "$(mktmpdir)" $env_dir
+  BUILDPACK_LOG_FILE="$log_file" compile "pre-post-build-scripts"
 
   # build info
   assertFileContains "node-package-manager=npm" $log_file
@@ -1084,7 +1082,7 @@ testBuildMetaData() {
 
   # erase the log file
   echo "" > $log_file
-  compile "yarn" "$(mktmpdir)" $env_dir
+  BUILDPACK_LOG_FILE="$log_file" compile "yarn"
 
   assertFileContains "node-package-manager=yarn" $log_file
   assertFileContains "has-node-lock-file=true" $log_file
@@ -1095,6 +1093,19 @@ testBuildMetaData() {
   assertFileContains "node-build-success=true" $log_file
 }
 
+testFailingBuildMetaData() {
+  local log_file=$(mktemp)
+
+  BUILDPACK_LOG_FILE="$log_file" compile "bad-json"
+  assertFileContains "failure=invalid-package-json" $log_file
+  assertCapturedError
+
+  echo "" > $log_file
+  BUILDPACK_LOG_FILE="$log_file" compile "yarn-lockfile-out-of-date"
+  assertFileContains "failure=outdated-yarn-lockfile" $log_file
+  assertCapturedError
+}
+
 testPropagateAppUUID() {
   env_dir=$(mktmpdir)
   local log_file=$(mktemp)