Return helpful response if any required header is missing

[gr2m]

follow up to https://github.com/probot/adapter-aws-lambda-serverless/pull/63

/cc @axel3rd I think that would have saved you a lot of headache.

[axel3rd]

Yes 🤯 ^^, but could be part of #60

[gr2m]

yes I agree. I'm just not sure how pointing to https://docs.aws.amazon.com/lambda/latest/dg/monitoring-cloudwatchlogs.html would be helpful?

Accessing Amazon CloudWatch logs for AWS Lambda - AWS Lambda

AWS Lambda automatically monitors Lambda functions on your behalf, reporting metrics through Amazon CloudWatch. To help you troubleshoot failures in a function, Lambda logs all requests handled by your function and also automatically stores logs generated by your code through Amazon CloudWatch Logs.

[axel3rd]

I'm just not sure how pointing to https://docs.aws.amazon.com/lambda/latest/dg/monitoring-cloudwatchlogs.html would be helpful?

IMO, the CloudWatch logs is easy to access from Monitoring Tab (and not sure than Lambda Insight can be relevant here).

Using Probot log can do the job (log.debug for input event, log.error in the error catch). And the HTTP content can depend of API integration (for sample I have never viewed a ooops message).

Accessing Amazon CloudWatch logs for AWS Lambda - AWS Lambda

AWS Lambda automatically monitors Lambda functions on your behalf, reporting metrics through Amazon CloudWatch. To help you troubleshoot failures in a function, Lambda logs all requests handled by your function and also automatically stores logs generated by your code through Amazon CloudWatch Logs.

[gr2m]

so in case of an error response, shall we include a JSON key such as

{
  "error": "...",
  "documentation_url": "https://docs.aws.amazon.com/lambda/latest/dg/monitoring-cloudwatchlogs.html"
}