elasticapm/contrib/serverless/aws_wrapper/elasticapm-lambda.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-

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import os
import shutil
import sys


class LambdaError(Exception):
    pass


if __name__ == "__main__":
    original_handler = os.environ.get("_HANDLER", None)
    if not original_handler:
        raise LambdaError("Cannot find original handler. _HANDLER is not set correctly.")

    # AWS Lambda's `/var/runtime/bootstrap.py` uses `imp.load_module` to load
    # the handler from "_HANDLER". This means that the handler will be reloaded
    # (even if it's already been loaded), and any instrumentation that we do
    # will be lost. Thus, we can't use our normal wrapper script, and must
    # replace the handler altogether and wrap it manually.
    os.environ["ELASTICAPM_ORIGINAL_HANDLER"] = original_handler
    os.environ["_HANDLER"] = "elasticapm_handler.lambda_handler"

    # Invoke the runtime
    args = sys.argv[1:]
    runtime = shutil.which(args[0])
    args = args[1:]
    os.execl(runtime, runtime, *args)