[Small story] What to do if "Error with child process: Building resource'awsToolkitSamLocalResource'" does not work when Lambda is locally executed by SAM from VS Code

wrap up

If the version of pip inside SAM and the version of local pip do not match, it may not work, so you need to modify the version of local pip.

Execution environment

problem

It may not work when you want to test in a local environment using the AWS Toolkit from VS Code's "Run Locally". For example, the following error.

Local invoke of SAM Application has ended.
Preparing to run app.lambda_handler locally...
Building SAM Application...
An error occurred trying to run SAM Application locally: Error with child process: Building resource 'awsToolkitSamLocalResource'
,Running PythonPipBuilder:ResolveDependencies
,Error: PythonPipBuilder:ResolveDependencies - Traceback (most recent call last):
  File "<string>", line 1, in <module>
TypeError: 'module' object is not callable

Cause (probably)

It seems that the issue that occurred in SAM has not been solved yet in VS Code's AWS Toolkit. GitHub : sam build fails for python3.7 functions with pip==19.3 installed If you try the same settings and execute the following command from the terminal, there is no problem even if the verison of SAM and pip are the same.

$ sam local invoke HelloWorldFunction --event events/event.json

Coping

Although it is a temporary measure, if you modify the version of pip to the following, it will be possible to execute normally even from VS Code.

$ pip install pip==19.2.3

Log "Run Locally" from VS Code after changing pip version

Fetching lambci/lambda:python3.7 Docker container image......
Mounting /tmp/aws-toolkit-vscode/vsctkytL1AY/output/awsToolkitSamLocalResource as /var/task:ro,delegated inside runtime container

...(Omission)...

{"statusCode":200,"body":"{\"message\": \"hello worldXXX\"}"}