How to fix "`The --custom_entrypoint flag must be set for custom runtimes`"?

Question

I get this error on appengine when I run gcloud preview app run app.yaml: The --custom_entrypoint flag must be set for custom runtimes

My app.yamllooks like:

version: 0-1-1
runtime: custom
vm: true
api_version: 1
manual_scaling:
  instances: 1

handlers:
  - url: .*
    script: dynamic

My dockerfile is just: FROM google/nodejs-runtime

I reinstalled gcloud to get the latest version, did something change in the yaml config for managed VMs? This makes it impossible for me to test my app.

Schmaltzy

There was an earlier bug with Google Cloud SDK version 0.9.65, but should have been fixed. Can you verify what SDK version you have by running: gcloud version Related question and workaround is at: #30945821 – Baghdad

FYI - I am also seeing this error with Google Cloud SDK 0.9.67. I'm checking for a workaround or fix. – Baghdad

Just to update, I rolled back to previous version 0.9.66 and no longer see the error. I ran: gcloud config set component_manager/fixed_sdk_version 0.9.66 -- To get back to latest, run: gcloud config unset component_manager/fixed_sdk_version – Baghdad

Thank you, this worked for me (don't forget to do gcloud components update after). – Schmaltzy

Answer 1

There appears to be a bug or setup issue with Google Cloud SDK version 0.9.67 causing this error. As a temporary workaround, you can revert to previous SDK version, which is working, with the following commands:

gcloud config set component_manager/fixed_sdk_version 0.9.66
gcloud components update

To return to the current version of the SDK, run:

gcloud config unset component_manager/fixed_sdk_version
gcloud components update

This issue appeared a few versions ago and was addressed here: Running node.js on google cloud, but error running with docker

Baghdad

Answer 2

You can run gcloud help preview app run to show a man page describing the run command and its parameters. --custom-entrypoint is described as:

 --custom-entrypoint CUSTOM_ENTRYPOINT
    Specify an entrypoint for custom runtime modules. This is required when
    such modules are present. Include "{port}" in the string (without
    quotes) to pass the port number in as an argument. For instance:
    --custom_entrypoint="gunicorn -b localhost:{port} mymodule:application"

Note that the error message says --custom_entrypoint, with an underscore, but the parameter is --customer_entrypoint, with a dash. The correct name is --custom-entrypoint see: https://code.google.com/p/google-cloud-sdk/issues/detail?id=191

For a nodejs you should be able to use something like:

gcloud preview app run app.yaml --project=your-project-id --custom-entrypoint "node index.js {port}"

Depending on how you start your application. The port seems to also be available as the environment variable PORT so you don't need to use {port} if your app does not handle command line arguments.

I haven't been able to use npm start or other npm run <script> from the --custom-entrypoint however.

Cottonseed

Answer 3

Comment lines 391 to 397 in

google-cloud-sdk/platform/google_appengine/google/appengine/tools/devappserver2/module.py

#      if (self._module_configuration.effective_runtime == 'custom' and
#          os.environ.get('GAE_LOCAL_VM_RUNTIME') != '0'):
#        if not self._custom_config.custom_entrypoint:
#          raise ValueError('The --custom_entrypoint flag must be set for '
#                           'custom runtimes')
#        else:
#          runtime_config.custom_config.CopyFrom(self._custom_config)

Imperturbation