Added Lambda and API Gateway request IDs to Cloudwatch logs when there's a PHP-FPM issue

src/Event/Http/FpmHandler.php

@@ -49,6 +49,11 @@ final class FpmHandler extends HttpHandler
  /** @var Process|null */
  private $fpm;
 
+ /** @var string */
+ private $lambdaRequestId;
+ /** @var string */
+ private $apiGatewayRequestId;
+
  public function __construct(string $handler, string $configFile = self::CONFIG)
  {
  $this->handler = $handler;
@@ -79,7 +84,7 @@ public function start(): void
  $this->fpm->setTimeout(null);
  $this->fpm->start(function ($type, $output): void {
  // Send any PHP-FPM log to CloudWatch
- echo $output;
+ $this->logToCloudwatch($output);
  });
 
  $this->client = new Client;
@@ -108,16 +113,19 @@ public function __destruct()
  */
  public function handleRequest(HttpRequestEvent $event, Context $context): HttpResponse
  {
+ $this->lambdaRequestId = $context->getAwsRequestId();
+ $this->apiGatewayRequestId = $event->getRequestContext()['requestId'] ?? null;
+
  $request = $this->eventToFastCgiRequest($event, $context);
 
  try {
  $response = $this->client->sendRequest($this->connection, $request);
  } catch (Throwable $e) {
- printf(
- "Error communicating with PHP-FPM to read the HTTP response. A root cause of this can be that the Lambda (or PHP) timed out, for example when trying to connect to a remote API or database, if this happens continuously check for those! Bref will restart PHP-FPM now. Original exception message: %s %s\n",
+ $this->logToCloudwatch(sprintf(
+ 'Error communicating with PHP-FPM to read the HTTP response. A root cause of this can be that the Lambda (or PHP) timed out, for example when trying to connect to a remote API or database, if this happens continuously check for those! Bref will restart PHP-FPM now. Original exception message: %s %s',
  get_class($e),
  $e->getMessage()
- );
+ ));
 
  // Restart PHP-FPM: in some cases PHP-FPM is borked, that's the only way we can recover
  $this->stop();
@@ -221,7 +229,7 @@ private function killExistingFpm(): void
 
  // Never seen this happen but just in case
  if ($pid <= 0) {
- echo "PHP-FPM's PID file contained an invalid PID, assuming PHP-FPM isn't running.\n";
+ $this->logToCloudwatch("PHP-FPM's PID file contained an invalid PID, assuming PHP-FPM isn't running.");
  unlink(self::SOCKET);
  unlink(self::PID_FILE);
  return;
@@ -243,12 +251,12 @@ private function killExistingFpm(): void
  return;
  }
 
- echo "PHP-FPM seems to be running already. This might be because Lambda stopped the bootstrap process but didn't leave us an opportunity to stop PHP-FPM (did Lambda timeout?). Stopping PHP-FPM now to restart from a blank slate.\n";
+ $this->logToCloudwatch("PHP-FPM seems to be running already. This might be because Lambda stopped the bootstrap process but didn't leave us an opportunity to stop PHP-FPM (did Lambda timeout?). Stopping PHP-FPM now to restart from a blank slate.");
 
  // The previous PHP-FPM process is running, let's try to kill it properly
  $result = posix_kill($pid, self::SIGTERM);
  if ($result === false) {
- echo "PHP-FPM's PID file contained a PID that doesn't exist, assuming PHP-FPM isn't running.\n";
+ $this->logToCloudwatch("PHP-FPM's PID file contained a PID that doesn't exist, assuming PHP-FPM isn't running.");
  unlink(self::SOCKET);
  unlink(self::PID_FILE);
  return;
@@ -282,4 +290,33 @@ private function getResponseHeaders(ProvidesResponseData $response): array
  {
  return array_change_key_case($response->getHeaders(), CASE_LOWER);
  }
+
+ /**
+ * Log a message to Cloudwatch, this is specific for FPM related errors and will include AWS Request IDs for the
+ * current Lambda invocation and API Gateway (where applicable) to aid debugging any FPM-related issues.
+ */
+ private function logToCloudwatch(string $message): void
+ {
+ echo trim($message) . ' ' . json_encode($this->getLogContext()) . PHP_EOL;
+ }
+
+ /**
+ * Returns an array with AWS Request IDs for the current Lambda invocation and API Gateway (where applicable)
+ *
+ * @return string[]|array
+ */
+ private function getLogContext(): array
+ {
+ $logContext = [];
+
+ if ($this->lambdaRequestId) {
+ $logContext['lambdaRequestId'] = $this->lambdaRequestId;
+ }
+
+ if ($this->apiGatewayRequestId) {
+ $logContext['apiGatewayRequestId'] = $this->apiGatewayRequestId;
+ }
+
+ return $logContext;
+ }
 }