Create runtime image

Author: clareliguori

Dockerfile

@@ -39,8 +39,11 @@ RUN mkdir bin && \
 RUN curl -sS https://getcomposer.org/installer | ./bin/php -- --install-dir=/runtime/bin --filename=composer && \
     ./bin/php ./bin/composer require guzzlehttp/guzzle
 
+# Copy in runtime bootstrap
+COPY runtime/bootstrap /runtime/
+
 ###### Create runtime image ######
 
 FROM lambci/lambda:provided as runtime
 
-COPY --from=builder /runtime /opt
+COPY --from=builder /runtime/ /opt/

runtime/bootstrap

@@ -0,0 +1,41 @@
+#!/opt/bin/php
+<?php
+
+// This invokes Composer's autoloader so that we'll be able to use Guzzle and any other 3rd party libraries we need.
+require __DIR__ . '/vendor/autoload.php';
+
+function getNextRequest()
+{
+    $client = new \GuzzleHttp\Client();
+    $response = $client->get('http://' . $_ENV['AWS_LAMBDA_RUNTIME_API'] . '/2018-06-01/runtime/invocation/next');
+
+    return [
+      'invocationId' => $response->getHeader('Lambda-Runtime-Aws-Request-Id')[0],
+      'payload' => json_decode((string) $response->getBody(), true)
+    ];
+}
+
+function sendResponse($invocationId, $response)
+{
+    $client = new \GuzzleHttp\Client();
+    $client->post(
+    'http://' . $_ENV['AWS_LAMBDA_RUNTIME_API'] . '/2018-06-01/runtime/invocation/' . $invocationId . '/response',
+       ['body' => $response]
+    );
+}
+
+// This is the request processing loop. Barring unrecoverable failure, this loop runs until the environment shuts down.
+do {
+    // Ask the runtime API for a request to handle.
+    $request = getNextRequest();
+
+    // Obtain the function name from the _HANDLER environment variable and ensure the function's code is available.
+    $handlerFunction = array_slice(explode('.', $_ENV['_HANDLER']), -1)[0];
+    require_once $_ENV['LAMBDA_TASK_ROOT'] . '/src/' . $handlerFunction . '.php';
+
+    // Execute the desired function and obtain the response.
+    $response = $handlerFunction($request['payload']);
+
+    // Submit the response back to the runtime API.
+    sendResponse($request['invocationId'], $response);
+} while (true);