# Copyright 2018 Google LLC
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# https://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import jinja2
import yaml
import re
import os
from typing import (Any, DefaultDict, Dict, Mapping, List)
from hashlib import sha256
from collections import (OrderedDict, defaultdict)
from gapic.samplegen_utils.utils import (
coerce_response_name, is_valid_sample_cfg)
from gapic.samplegen_utils.types import InvalidConfig
from gapic.samplegen import (manifest, samplegen)
from gapic.generator import options
from gapic.generator import formatter
from gapic.schema import api
from gapic import utils
from google.protobuf.compiler.plugin_pb2 import CodeGeneratorResponse
[docs]class Generator:
"""A protoc code generator for client libraries.
This class provides an interface for getting a
:class:`~.plugin_pb2.CodeGeneratorResponse` for an :class:`~api.API`
schema object (which it does through rendering templates).
Args:
opts (~.options.Options): An options instance.
templates (str): Optional. Path to the templates to be
rendered. If this is not provided, the templates included with
this application are used.
"""
def __init__(self, opts: options.Options) -> None:
# Create the jinja environment with which to render templates.
self._env = jinja2.Environment(
loader=jinja2.FileSystemLoader(searchpath=opts.templates),
undefined=jinja2.StrictUndefined,
extensions=["jinja2.ext.do"],
)
# Add filters which templates require.
self._env.filters['rst'] = utils.rst
self._env.filters['snake_case'] = utils.to_snake_case
self._env.filters['sort_lines'] = utils.sort_lines
self._env.filters['wrap'] = utils.wrap
self._env.filters['coerce_response_name'] = coerce_response_name
self._sample_configs = opts.sample_configs
[docs] def get_response(self, api_schema: api.API) -> CodeGeneratorResponse:
"""Return a :class:`~.CodeGeneratorResponse` for this library.
This is a complete response to be written to (usually) stdout, and
thus read by ``protoc``.
Args:
api_schema (~api.API): An API schema object.
Returns:
~.CodeGeneratorResponse: A response describing appropriate
files and contents. See ``plugin.proto``.
"""
output_files: Dict[str, CodeGeneratorResponse.File] = OrderedDict()
sample_templates, client_templates = utils.partition(
lambda fname: os.path.basename(
fname) == samplegen.DEFAULT_TEMPLATE_NAME,
self._env.loader.list_templates())
# Iterate over each template and add the appropriate output files
# based on that template.
# Sample templates work differently: there's (usually) only one,
# and instead of iterating over it/them, we iterate over samples
# and plug those into the template.
for template_name in client_templates:
# Sanity check: Skip "private" templates.
filename = template_name.split('/')[-1]
if filename.startswith('_') and filename != '__init__.py.j2':
continue
# Append to the output files dictionary.
output_files.update(self._render_template(template_name,
api_schema=api_schema,
))
output_files.update(self._generate_samples_and_manifest(api_schema))
# Return the CodeGeneratorResponse output.
return CodeGeneratorResponse(file=[i for i in output_files.values()])
def _generate_samples_and_manifest(
self,
api_schema: api.API
) -> Dict[str, CodeGeneratorResponse.File]:
"""Generate samples and samplegen manifest for the API.
Arguments:
api_schema (api.API): The schema for the API to which the samples belong.
Returns:
Dict[str, CodeGeneratorResponse.File]: A dict mapping filepath to rendered file.
"""
id_to_samples: DefaultDict[str, List[Any]] = defaultdict(list)
for config_fpath in self._sample_configs:
with open(config_fpath) as f:
configs = yaml.safe_load_all(f.read())
spec_generator = (
spec
for cfg in configs if is_valid_sample_cfg(cfg)
for spec in cfg.get("samples", [])
)
for spec in spec_generator:
# Every sample requires an ID, preferably provided by the
# samplegen config author.
# If no ID is provided, fall back to the region tag.
# If there's no region tag, generate a unique ID.
#
# Ideally the sample author should pick a descriptive, unique ID,
# but this may be impractical and can be error-prone.
sample_id = (spec.get("id")
or spec.get("region_tag")
or sha256(str(spec).encode('utf8')).hexdigest()[:8])
spec["id"] = sample_id
id_to_samples[sample_id].append(spec)
out_dir = "samples"
fpath_to_spec_and_rendered = {}
for samples in id_to_samples.values():
for spec in samples:
id_is_unique = len(samples) == 1
# The ID is used to generate the file name and by sample tester
# to link filenames to invoked samples. It must be globally unique.
if not id_is_unique:
spec_hash = sha256(
str(spec).encode('utf8')).hexdigest()[:8]
spec["id"] += f"_{spec_hash}"
sample = samplegen.generate_sample(spec, self._env, api_schema)
fpath = spec["id"] + ".py"
fpath_to_spec_and_rendered[os.path.join(out_dir, fpath)] = (spec,
sample)
output_files = {
fname: CodeGeneratorResponse.File(
content=formatter.fix_whitespace(sample),
name=fname
)
for fname, (_, sample) in fpath_to_spec_and_rendered.items()
}
# Only generate a manifest if we generated samples.
if output_files:
manifest_fname, manifest_doc = manifest.generate(
((fname, spec)
for fname, (spec, _) in fpath_to_spec_and_rendered.items()),
api_schema
)
manifest_fname = os.path.join(out_dir, manifest_fname)
output_files[manifest_fname] = CodeGeneratorResponse.File(
content=manifest_doc.render(),
name=manifest_fname
)
return output_files
def _render_template(
self,
template_name: str, *,
api_schema: api.API,
) -> Dict[str, CodeGeneratorResponse.File]:
"""Render the requested templates.
Args:
template_name (str): The template to be rendered.
It is expected that these come from
:class:`jinja2.FileSystemLoader`, and they should be
able to be sent to the :meth:`jinja2.Environment.get_template`
method.
api_schema (~.api.API): An API schema object.
Returns:
Sequence[~.CodeGeneratorResponse.File]: A sequence of File
objects for inclusion in the final response.
"""
answer: Dict[str, CodeGeneratorResponse.File] = OrderedDict()
skip_subpackages = False
# Sanity check: Rendering per service and per proto would be a
# combinatorial explosion and is almost certainly not what anyone
# ever wants. Error colorfully on it.
if '$service' in template_name and '$proto' in template_name:
raise ValueError('Template files may live under a $proto or '
'$service directory, but not both.')
# If this template should be rendered for subpackages, process it
# for all subpackages and set the strict flag (restricting what
# services and protos we pull from for the remainder of the method).
if '$sub' in template_name:
for subpackage in api_schema.subpackages.values():
answer.update(self._render_template(template_name,
api_schema=subpackage,
))
skip_subpackages = True
# If this template should be rendered once per proto, iterate over
# all protos to be rendered
if '$proto' in template_name:
for proto in api_schema.protos.values():
if (skip_subpackages and proto.meta.address.subpackage !=
api_schema.subpackage_view):
continue
answer.update(self._get_file(template_name,
api_schema=api_schema,
proto=proto
))
return answer
# If this template should be rendered once per service, iterate
# over all services to be rendered.
if '$service' in template_name:
for service in api_schema.services.values():
if (skip_subpackages and service.meta.address.subpackage !=
api_schema.subpackage_view):
continue
answer.update(self._get_file(template_name,
api_schema=api_schema,
service=service,
))
return answer
# This file is not iterating over anything else; return back
# the one applicable file.
answer.update(self._get_file(template_name, api_schema=api_schema))
return answer
def _get_file(self, template_name: str, *,
api_schema=api.API,
**context: Mapping):
"""Render a template to a protobuf plugin File object."""
# Determine the target filename.
fn = self._get_filename(template_name,
api_schema=api_schema,
context=context,
)
# Render the file contents.
cgr_file = CodeGeneratorResponse.File(
content=formatter.fix_whitespace(
self._env.get_template(template_name).render(
api=api_schema,
**context
),
),
name=fn,
)
# Sanity check: Do not render empty files.
if (utils.empty(cgr_file.content) and
not fn.endswith(('py.typed', '__init__.py'))):
return {}
# Return the filename and content in a length-1 dictionary
# (because we track output files overall in a dictionary).
return {fn: cgr_file}
def _get_filename(
self,
template_name: str, *,
api_schema: api.API,
context: dict = None,
) -> str:
"""Return the appropriate output filename for this template.
This entails running the template name through a series of
replacements to replace the "filename variables" (``$name``,
``$service``, etc.).
Additionally, any of these variables may be substituted with an
empty value, and we should do the right thing in this case.
(The exception to this is ``$service``, which is guaranteed to be
set if it is needed.)
Args:
template_name (str): The filename of the template, from the
filesystem, relative to ``templates/``.
api_schema (~.api.API): An API schema object.
context (Mapping): Additional context being sent to the template.
Returns:
str: The appropriate output filename.
"""
filename = template_name[:-len('.j2')]
# Replace the $namespace variable.
filename = filename.replace(
'$namespace',
os.path.sep.join([i.lower() for i in api_schema.naming.namespace]),
).lstrip(os.path.sep)
# Replace the $name, $version, and $sub variables.
filename = filename.replace('$name_$version',
api_schema.naming.versioned_module_name)
filename = filename.replace('$version', api_schema.naming.version)
filename = filename.replace('$name', api_schema.naming.module_name)
filename = filename.replace('$sub',
'/'.join(api_schema.subpackage_view))
# Replace the $service variable if applicable.
if context and 'service' in context:
filename = filename.replace(
'$service',
context['service'].module_name,
)
# Replace the $proto variable if appliable.
# In the cases of protos, we also honor subpackages.
if context and 'proto' in context:
filename = filename.replace(
'$proto',
context['proto'].module_name,
)
# Paths may have empty path segments if components are empty
# (e.g. no $version); handle this.
filename = re.sub(r'/+', '/', filename)
# Done, return the filename.
return filename
__all__ = (
'Generator',
)