JSON logging support

[sean-r-williams]

AWS Lambda offers support for both plain-text and JSON format logs.

Lambda exposes this configuration via the AWS_LAMBDA_LOG_FORMAT environment variable. It's currently missing from the environment variable documentation (see case 175226052300866), but the variable appears to be set to either Text or JSON depending on customer configuration.

There's a couple of aspects to supporting this:

• Runtime-intrinsic logs (e.g. anything that's Write-Host '[RUNTIME-<...>')
• Customer logs that use:
  • Unstructured string-only logs (Write-Debug, -Verbose, -Warning)
  • Unstructured partially-formatted logs (Write-Host)
  • Structured logs via Write-Information
• Implicit log events (e.g. ErrorRecords generated from parser errors)