本地测试时Lambda超时

Question

Problem

I'm testing an AWS Lambda function locally, but my container hits a timeout after 300 seconds. I've been doing some research and have already read some AWS documents about this , besides this document I also read other StackOverflow questions .

Context

I'm developing with Python and use Sentry to get telemetry about my function. When building the container to test things locally I use the following Dockerfile:

FROM public.ecr.aws/lambda/python:3.8

# Install the function's dependencies using file requirements.txt
# from your project folder.
COPY requirements.txt .
RUN pip install --upgrade pip -q
RUN pip install wheel
RUN pip install -r requirements.txt --target "${LAMBDA_TASK_ROOT}"

# Copy function code
COPY main.py ${LAMBDA_TASK_ROOT}
COPY misc/* ./misc/
COPY sql/* ./sql/

# Set the CMD to your handler (could be done as a parameter override)
CMD [ "main.lambda_handler" ]

And I create my API requests through Postman. Based on this I already checked if the timeout was originating in Postman or Sentry, but timeout settings in these tools are set above the 300 second timeout I'm getting. I've come to believe the timeout could be coming from the Docker image I'm using , but haven't found information about this online. To manage AWS related things in the code I import the boto3 library and also suspect the setting I'm looking for could be related to this library.

The lambda that's in production already has a timeout set to the 15-minute max allowed by AWS, but when testing locally the problem appears. I've also checked if the Access Keys I'm using to execute things locally have a timeout, but haven't found anything pointing in this direction.

I'm new to developing on AWS Lambda services so this might be some very basic stuff, thank you!

Answer 1

Your guess is correct. There is a default timeout in AWS Lambda Runtime Interface Emulator and it is 300 seconds. See its repo on GitHub. And specific line that shows it.

If you need to increase it, you'll have to pass it as ENV variable to docker.