No way to specify `python_gapic_opt` flag with `py_gapic_library` rule

[aohren]

We need to replicate the following protoc invocation from Bazel rule py_gapic_library. In particular, there's no current way to set --python_gapic_opt to the desired value below:

  protoc google/ads/googleads/${VERSION}/**/*.proto \
    --proto_path="${COMMON_PROTOS_PATH}" \
    --proto_path=. \
    --python_gapic_out=${OUTPUT_DIR} \
    --plugin=${GAPIC_GENERATOR_PATH}/gapic/cli/generate.py=python_gapic \
    --python_gapic_opt="old-naming,lazy-import,python-gapic-name=${GAPIC_NAME},python-gapic-templates=${GAPIC_GENERATOR_PATH}/gapic/ads-template"

where one var is custom:

GAPIC_NAME is googleads.

And the other vars are what you'd expect:

COMMON_PROTOS_PATH is api-common-protos dependencies
GAPIC_GENERATOR_PATH is root of gapic-generator-python

[aohren]

Output from a bazel build --verbose_failures run:

https://drive.google.com/a/google.com/file/d/1oKBkNbG6_wjwlNvS8F34CHQFBmLIpM8N/view?usp=sharing

[BenRKarl]

@aohren there's an updated value for python-gapic-templates now, it should point to the /gapic/ads-templates directory on the master branch of this repository.

[aohren]

@BenRKarl thanks for that. I've edited the original issue in-place to reflect the updated protoc arguments.

[vam-google]

Should be fixed in #411. Closing.

[software-dov]

Should be fixed by #402