A proof of concept for attaching a debugger to a lambda running in AWS.

We use a custom Lambda runtime to open a tcp tunnel with ngrok and start nodejs with debugging enabled.

• Register for a free ngrok account at https://dashboard.ngrok.com/signup
• Get your ngrok auth token here https://dashboard.ngrok.com/auth
• Add the ngrok config file to ./debug_layer/bin/ngrok.yaml
  • See the example ngrok config file ./debug_layer/bin/ngrok.yaml.example for formatting

$ sls deploy

• $ sls invoke -f runTest -d '{"foo": "bar"}'
• Go to the ngrok dashboard and find your tunnel address https://dashboard.ngrok.com/status
• Open the chrome debugger chrome://inspect/#devices
• Click Open dedicated DevTools for Node and then Add Connection
  • Do not include the tcp protocol when pasting the connection, ex. 0.tcp.ngrok.io:18160
• The debugger should connect automatically and hit the top level breakpoint
• Click the play button to move to the next breakpoint, which is preconfigured to stop when the handler file has been loaded
• Your lambda function package will be located under file://var/task

• When you invoke your lambda the first time, the ngrok tunnel address may change a few times. You should refresh the ngrok dashboard a few times until the address seems stable. If you can't connect, go back to your dashboard and check if the address has changed.
• If the ngrok process dies, you'll have to redeploy to force the running lambda to stop or wait for AWS to kill it for you.