Add transcoding best-practice example

.gitmodules

@@ -0,0 +1,6 @@
+[submodule "examples/transcoding/best-practice/bp-api/third_party/protovalidate"]
+	path = examples/transcoding/best-practice/bp-api/third_party/protovalidate
+	url = https://github.com/bufbuild/protovalidate
+[submodule "examples/transcoding/best-practice/bp-api/third_party/googleapis"]
+	path = examples/transcoding/best-practice/bp-api/third_party/googleapis
+	url = https://github.com/googleapis/googleapis

build.gradle

@@ -77,7 +77,7 @@ allprojects {
             endWithNewline()
             palantirJavaFormat()
 
-            targetExclude "build/generated/**"
+            targetExclude "**/generated/**"
 
             custom("Refuse wildcard imports", {
                 if (it =~ /\nimport .*\*;/) {

examples/transcoding/best-practice/bp-api/README.md

@@ -0,0 +1,32 @@
+## Project Configuration
+
+Using [buf](https://buf.build/) to manage proto files.
+
+[protoc-gen-openapi](https://github.com/google/gnostic/blob/main/cmd/protoc-gen-openapi/README.md) is not in the [Buf Schema Registry](https://buf.build/plugins), 
+so it can't use it directly with buf [remote plugin](https://buf.build/docs/generate/overview#generating-with-remote-plugins).
+
+Refer to [issues#821](https://github.com/bufbuild/plugins/issues/821).
+
+To use `protoc-gen-openapi` with buf, you can use the following steps:
+
+1. Install `protoc-gen-openapi`
+
+    ```bash
+    go install github.com/google/gnostic/cmd/protoc-gen-openapi@latest
+    ```
+
+2. Use as local plugin in buf.gen.yaml
+
+    ```yaml
+    plugins:
+      - local: protoc-gen-openapi
+        out: gen/openapi
+    ```
+
+    Make sure $GOPATH/bin is in your PATH: `export PATH="PATH:$(go env GOPATH)/bin"`
+
+## Generate Code
+
+```bash
+cd examples/transcoding/best-practice/bp-api && buf generate
+```

examples/transcoding/best-practice/bp-api/api/user/v1/user.proto

@@ -0,0 +1,50 @@
+syntax = "proto3";
+
+package user.v1;
+
+import "google/api/annotations.proto";
+import "buf/validate/validate.proto";
+
+option java_multiple_files = true;
+option go_package = "github.com/your/repo/user/v1;user_v1";
+
+message User {
+  int64 id = 1;
+  string name = 2;
+}
+
+message GetUserRequest {
+  int64 id = 1 [(buf.validate.field).int64 = {
+    gte: 0
+  }];
+}
+
+message GetUserResponse {
+  User user = 1;
+}
+
+message DeleteUserRequest {
+  int64 id = 1 [(buf.validate.field).int64 = {
+    gte: 0
+  }];
+}
+
+message DeleteUserResponse {
+
+}
+
+service UserService {
+  // Get a user by ID.
+  rpc GetUser(GetUserRequest) returns (GetUserResponse) {
+    option (google.api.http) = {
+      get: "/v1/users/{id}"
+    };
+  }
+
+  // Delete a user by ID.
+  rpc DeleteUser(DeleteUserRequest) returns (DeleteUserResponse) {
+    option (google.api.http) = {
+      delete: "/v1/users/{id}"
+    };
+  }
+}

examples/transcoding/best-practice/bp-api/buf.gen.yaml

@@ -0,0 +1,16 @@
+version: v2
+plugins:
+  # Java
+  - remote: buf.build/grpc/java:v1.64.0
+    out: generated/java
+  - remote: buf.build/protocolbuffers/java:v25.1
+    out: generated/java
+
+  # OpenAPI
+  - local: protoc-gen-openapi
+    out: generated/openapi
+    opt:
+      - fq_schema_naming=true
+      - enum_type=string
+
+  # Other languages ...

examples/transcoding/best-practice/bp-api/buf.lock

@@ -0,0 +1,9 @@
+# Generated by buf. DO NOT EDIT.
+version: v2
+deps:
+  - name: buf.build/bufbuild/protovalidate
+    commit: 46a4cf4ba1094a34bcd89a6c67163b4b
+    digest: b5:2076a950fdf4a8047064d55fd1d20ef21e6d745bf56e3edf557071abd4488ed48c9466d60831d8a03489dc1fcc8ceaa073d197411b59ecd873e28b1328034e0b
+  - name: buf.build/googleapis/googleapis
+    commit: f0e53af8f2fc4556b94f482688b57223
+    digest: b5:24e758f963ee1bb3b5218eb452e0bdfb7a5449d9a77d174b8284b6368ccc1884213689381cdcd79e4231796c281c128ac1ae50825237b1774deb542bdc704b32

examples/transcoding/best-practice/bp-api/buf.yaml

@@ -0,0 +1,11 @@
+# https://buf.build/docs/configuration/v2/buf-yaml
+
+version: v2
+modules:
+  - path: api
+deps:
+  - buf.build/googleapis/googleapis
+  - buf.build/bufbuild/protovalidate
+lint:
+  use:
+    - DEFAULT

examples/transcoding/best-practice/bp-api/build.gradle

@@ -0,0 +1,12 @@
+dependencies {
+    api("io.grpc:grpc-protobuf")
+    api(project(":grpc-starters:grpc-starter-protovalidate"))
+}
+
+sourceSets {
+    main {
+        java {
+            srcDirs "generated/java"
+        }
+    }
+}