lambda_executor.py

#!/usr/bin/env python3
import os
import sys
import json
import base64
import boto3
from botocore.client import Config

def main():
    with open(sys.argv[1]) as file:
        command = file.read()

    # the prefix CUSTOM_ENV is added by gitlab, see:
    # https://docs.gitlab.com/runner/executors/custom.html#stages
    job_environment = {
        name[len("CUSTOM_ENV_"):] : value
        for name, value in os.environ.items()
        if name.startswith("CUSTOM_ENV_")
    }


    payload = json.dumps({
        "command": command,
        "environment": job_environment,
    })

    # we put a high read_timeout in order to let the lambda the time to finish
    client = boto3.client('lambda', region_name="<AWS_REGION>", config=Config(read_timeout=1200))
    response = client.invoke(
        FunctionName='<YOUR_LAMBDA_FUNCTION_ARN>',
        Payload=payload,
        LogType='Tail'
    )

    json_result = response['Payload'].read().decode('utf-8')
    result = json.loads(json_result)
    print(result["output"])

    # there was an error during the CI job, we need to tell
    # the gitlab runner the job has failed
    if result["return_code"] != 0:
        # we terminate as recommanded by gitlab documentation
        # https://docs.gitlab.com/runner/executors/custom.html#build-failure
        exit(os.environ["BUILD_FAILURE_EXIT_CODE"])

if __name__ == "__main__":
    main()