cleanup(generator): parse api version from url pattern (#14595)

* cleanup(generator): parse api version from url pattern

* format

* add tests

* format

* make regex string static

* format

Author: cuiy0006

generator/internal/http_option_utils.cc

@@ -264,7 +264,6 @@ void SetHttpQueryParameters(HttpExtensionInfo const& info,
 HttpExtensionInfo ParseHttpExtension(
     google::protobuf::MethodDescriptor const& method) {
   if (!method.options().HasExtension(google::api::http)) return {};
-  auto api_version = FormatApiVersionFromPackageName(method);
 
   HttpExtensionInfo info;
   google::api::HttpRule http_rule =
@@ -322,6 +321,9 @@ HttpExtensionInfo ParseHttpExtension(
     out->append(absl::visit(SegmentAsStringVisitor{}, s->value));
   };
 
+  auto api_version =
+      FormatApiVersionFromUrlPattern(url_pattern, method.file()->name());
+
   auto rest_path_visitor = RestPathVisitor(api_version, info.rest_path);
   for (auto const& s : parsed_http_rule->segments) {
     if (absl::holds_alternative<PathTemplate::Variable>(s->value)) {
@@ -392,6 +394,22 @@ std::string FormatApiVersionFromPackageName(
   return {};  // Suppress clang-tidy warnings
 }
 
+// Generate api version by extracting the version from the url pattern.
+// In some cases(i.e. location), there is no version in the package name.
+std::string FormatApiVersionFromUrlPattern(std::string const& url_pattern,
+                                           std::string const& file_name) {
+  std::vector<std::string> parts = absl::StrSplit(url_pattern, '/');
+  static std::regex const kRe{R"(v\d+)"};
+  for (auto const& part : parts) {
+    if (std::regex_match(part, kRe)) {
+      return part;
+    }
+  }
+  GCP_LOG(FATAL) << "Unrecognized API version in file: " << file_name
+                 << ", url pattern: " << url_pattern;
+  return {};  // Suppress clang-tidy warnings
+}
+
 }  // namespace generator_internal
 }  // namespace cloud
 }  // namespace google

generator/internal/http_option_utils.h

@@ -112,6 +112,12 @@ std::string FormatRequestResource(google::protobuf::Descriptor const& request,
 std::string FormatApiVersionFromPackageName(
     google::protobuf::MethodDescriptor const& method);
 
+/**
+ * Parses the url pattern of the method and returns its API version.
+ */
+std::string FormatApiVersionFromUrlPattern(std::string const& url_pattern,
+                                           std::string const& file_name);
+
 }  // namespace generator_internal
 }  // namespace cloud
 }  // namespace google

generator/internal/http_option_utils_test.cc

@@ -772,6 +772,25 @@ TEST_F(HttpOptionUtilsTest, FormatApiVersionFromPackageNameError) {
       "google/foo/v1/service_without_version.proto, package: my.service");
 }
 
+TEST_F(HttpOptionUtilsTest, FormatApiVersionFromUrlPattern) {
+  std::string file_name = "google/foo/v1/service.proto";
+  std::string url_pattern_v1 = "/v1/foo/bar";
+  EXPECT_THAT(FormatApiVersionFromUrlPattern(url_pattern_v1, file_name),
+              Eq("v1"));
+  std::string url_pattern_v2 = "/foo/v2/bar";
+  EXPECT_THAT(FormatApiVersionFromUrlPattern(url_pattern_v2, file_name),
+              Eq("v2"));
+}
+
+TEST_F(HttpOptionUtilsTest, FormatApiVersionFromUrlPatternError) {
+  std::string file_name = "google/foo/v1/service.proto";
+  std::string url_pattern = "/foo/bar";
+  EXPECT_DEATH_IF_SUPPORTED(
+      FormatApiVersionFromUrlPattern(url_pattern, file_name),
+      "Unrecognized API version in file: "
+      "google/foo/v1/service.proto, url pattern: /foo/bar");
+}
+
 }  // namespace
 }  // namespace generator_internal
 }  // namespace cloud