googleapis · gcf-merge-on-green · Mar 3, 2021 · Mar 2, 2021 · Mar 2, 2021 · Mar 3, 2021
diff --git a/gapic/generator/generator.py b/gapic/generator/generator.py
@@ -105,11 +105,12 @@ def get_response(
                     template_name, api_schema=api_schema, opts=opts)
             )
 
-        output_files.update(
-            self._generate_samples_and_manifest(
-                api_schema, self._env.get_template(sample_templates[0]),
-            )
-        )
+        sample_output = self._generate_samples_and_manifest(
+            api_schema,
+            self._env.get_template(sample_templates[0]),
+        ) if sample_templates else {}
+
+        output_files.update(sample_output)
 
         # Return the CodeGeneratorResponse output.
         res = CodeGeneratorResponse(
@@ -233,6 +234,10 @@ def _render_template(
         answer: Dict[str, CodeGeneratorResponse.File] = OrderedDict()
         skip_subpackages = False
 
+        # Very, very special case. This flag exists to gate this one file.
+        if not opts.metadata and template_name.endswith("gapic_metadata.json.j2"):
+            return answer
+
         # 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.

diff --git a/gapic/utils/options.py b/gapic/utils/options.py
@@ -41,20 +41,22 @@ class Options:
     lazy_import: bool = False
     old_naming: bool = False
     add_iam_methods: bool = False
+    metadata: bool = False
     # TODO(yon-mg): should there be an enum for transport type?
     transport: List[str] = dataclasses.field(default_factory=lambda: [])
 
     # Class constants
     PYTHON_GAPIC_PREFIX: str = 'python-gapic-'
     OPT_FLAGS: FrozenSet[str] = frozenset((
+        'add-iam-methods',      # microgenerator implementation for `reroute_to_grpc_interface`
+        'lazy-import',          # requires >= 3.7
+        'metadata',             # generate GAPIC metadata JSON file
         'old-naming',           # TODO(dovs): Come up with a better comment
         'retry-config',         # takes a path
         'samples',              # output dir
-        'lazy-import',          # requires >= 3.7
-        'add-iam-methods',      # microgenerator implementation for `reroute_to_grpc_interface`
         # transport type(s) delineated by '+' (i.e. grpc, rest, custom.[something], etc?)
         'transport',
-        'warehouse-package-name'  # change the package name on PyPI
+        'warehouse-package-name',  # change the package name on PyPI
     ))
 
     @classmethod
@@ -143,6 +145,7 @@ def tweak_path(p):
             lazy_import=bool(opts.pop('lazy-import', False)),
             old_naming=bool(opts.pop('old-naming', False)),
             add_iam_methods=bool(opts.pop('add-iam-methods', False)),
+            metadata=bool(opts.pop('metadata', False)),
             # transport should include desired transports delimited by '+', e.g. transport='grpc+rest'
             transport=opts.pop('transport', ['grpc'])[0].split('+')
         )

diff --git a/tests/unit/generator/test_generator.py b/tests/unit/generator/test_generator.py
@@ -116,6 +116,22 @@ def test_get_response_fails_invalid_file_paths():
         assert "%proto" in ex_str and "%service" in ex_str
 
 
+def test_get_response_ignore_gapic_metadata():
+    g = make_generator()
+    with mock.patch.object(jinja2.FileSystemLoader, "list_templates") as lt:
+        lt.return_value = ["gapic/gapic_metadata.json.j2"]
+        with mock.patch.object(jinja2.Environment, "get_template") as gt:
+            gt.return_value = jinja2.Template(
+                "This is not something we want to see")
+            res = g.get_response(
+                api_schema=make_api(),
+                opts=Options.build(""),
+            )
+
+            # We don't expect any files because opts.metadata is not set.
+            assert res.file == CodeGeneratorResponse().file
+
+
 def test_get_response_ignores_unwanted_transports_and_clients():
     g = make_generator()
     with mock.patch.object(jinja2.FileSystemLoader, "list_templates") as lt:

diff --git a/tests/unit/generator/test_options.py b/tests/unit/generator/test_options.py
@@ -14,6 +14,7 @@
 
 import os
 import pytest
+import re
 from unittest import mock
 import warnings
 
@@ -139,21 +140,24 @@ def test_options_service_config(fs):
     assert opts.retry == expected_cfg
 
 
-def test_options_lazy_import():
-    opts = Options.build('lazy-import')
-    assert opts.lazy_import
-
-
-def test_options_old_naming():
-    opts = Options.build('old-naming')
-    assert opts.old_naming
-
-
-def test_options_add_iam_methods():
-    opts = Options.build('add-iam-methods')
-    assert opts.add_iam_methods
-
-
-def test_options_warehouse_package_name():
-    opts = Options.build('warehouse-package-name')
-    assert opts.warehouse_package_name
+def test_options_bool_flags():
+    # All these options are default False.
+    # If new options violate this assumption,
+    # this test may need to be tweaked.
+    # New options should follow the dash-case/snake_case convention.
+    opt_str_to_attr_name = {
+        name: re.sub(r"-", "_", name)
+        for name in
+        ["lazy-import",
+         "old-naming",
+         "add-iam-methods",
+         "metadata",
+         "warehouse-package-name",
+         ]}
+
+    for opt, attr in opt_str_to_attr_name.items():
+        options = Options.build("")
+        assert not getattr(options, attr)
+
+        options = Options.build(opt)
+        assert getattr(options, attr)