gcloud beta app gen-config

NAME: gcloud beta app gen-config - generate missing configuration files for a source directory
SYNOPSIS: gcloud beta app gen-config [SOURCE_DIR] [--config=CONFIG] [--custom] [--runtime=RUNTIME] [GCLOUD_WIDE_FLAG …]
DESCRIPTION: (BETA) (DEPRECATED) This command is deprecated and will soon be removed.
As an alternative, create an app.yaml file yourself using the directions at https://cloud.google.com/appengine/docs/flexible/reference/app-yaml (App Engine flexible environment) or https://cloud.google.com/appengine/docs/standard/reference/app-yaml (App Engine standard environment) under the tab for your language.
To create a custom runtime, please follow the instructions at https://cloud.google.com/appengine/docs/flexible/custom-runtimes/ This command generates all relevant config files (app.yaml, Dockerfile and a build Dockerfile) for your application in the current directory or emits an error message if the source directory contents are not recognized.
EXAMPLES: To generate configs for the current directory:
gcloud beta app gen-config

To generate configs for ~/my_app:
gcloud beta app gen-config ~/my_app
POSITIONAL ARGUMENTS: [SOURCE_DIR]

The source directory to fingerprint.
FLAGS: --config=CONFIG

The yaml file defining the service configuration. This is normally one of the generated files, but when generating a custom runtime there can be an app.yaml containing parameters.

--custom

If true, generate config files for a custom runtime. This will produce a Dockerfile, a .dockerignore file and an app.yaml (possibly other files as well, depending on the runtime).

--runtime=RUNTIME

Generate config files for a given runtime. Can be used in conjunction with --custom. Allowed runtimes are: contrib-dart, dart, go, php, php55, php72, python, python27, python-compat, java, java7, java8, nodejs, ruby, go111, go112.
GCLOUD WIDE FLAGS: These flags are available to all commands: --access-token-file, --account, --billing-project, --configuration, --flags-file, --flatten, --format, --help, --impersonate-service-account, --log-http, --project, --quiet, --trace-token, --user-output-enabled, --verbosity.
Run $ gcloud help for details.
NOTES: This command is currently in beta and might change without notice.