feat(protoc-gen-elixir-gprc): add elixir grpc plugin (#11)

Signed-off-by: Yordis Prieto <yordis.prieto@gmail.com>

Author: yordis

.github/.release-please-config.json

@@ -24,6 +24,9 @@
   "packages": {
     "cmd/protoc-gen-connect-go-servicestruct": {
       "component": "protoc-gen-connect-go-servicestruct"
+    },
+    "cmd/protoc-gen-elixir-grpc": {
+      "component": "protoc-gen-elixir-grpc"
     }
   },
   "plugins": [

.gitignore

@@ -31,6 +31,6 @@ go.work.sum
 # .idea/
 # .vscode/
 
-# Generated build files
-protoc-gen-connect-go-servicestruct
-protoc-gen-connect-go-servicestruct.wasm
+# Generated protoc plugin binaries (root directory only)
+/protoc-gen-*
+/protoc-gen-*.wasm

Taskfile.yml

@@ -69,10 +69,23 @@ tasks:
       - go build ./...
 
   build-plugin:
-    desc: Build the protoc plugin binary
+    desc: Build all protoc plugin binaries
     cmds:
-      - echo "Building protoc plugin binary..."
+      - echo "Building protoc plugin binaries..."
       - go build -o protoc-gen-connect-go-servicestruct ./cmd/protoc-gen-connect-go-servicestruct
+      - go build -o protoc-gen-elixir-grpc ./cmd/protoc-gen-elixir-grpc
+
+  build-plugin-go:
+    desc: Build the Go Connect protoc plugin binary
+    cmds:
+      - echo "Building Go Connect protoc plugin binary..."
+      - go build -o protoc-gen-connect-go-servicestruct ./cmd/protoc-gen-connect-go-servicestruct
+
+  build-plugin-elixir:
+    desc: Build the Elixir gRPC protoc plugin binary
+    cmds:
+      - echo "Building Elixir gRPC protoc plugin binary..."
+      - go build -o protoc-gen-elixir-grpc ./cmd/protoc-gen-elixir-grpc
 
   dev-test:
     desc: Development workflow - fmt, vet, and generate coverage HTML

cmd/protoc-gen-elixir-grpc/README.md

@@ -0,0 +1,86 @@
+# protoc-gen-elixir-grpc
+
+A protobuf compiler plugin that generates Elixir gRPC server modules with `defdelegate` patterns 
+for clean handler organization. **Requires `protoc-gen-elixir` as a dependency.**
+
+## How-tos
+
+### Installation
+
+```bash
+go install github.com/TrogonStack/protoc-gen/cmd/protoc-gen-elixir-grpc@latest
+```
+
+### Basic Usage
+
+**Required**: This plugin must be used alongside `protoc-gen-elixir` as it generates server modules that reference 
+the protobuf message and service definitions:
+
+```bash
+protoc --elixir_out=lib --elixir-grpc_out=lib path/to/greeter.proto
+```
+
+### With buf
+
+**Required**: Add to your `buf.gen.yaml` alongside the required `protoc-gen-elixir` plugin:
+
+```yaml
+version: v2
+plugins:
+  - local: protoc-gen-elixir  # Required dependency
+    out: lib
+  - local: protoc-gen-elixir-grpc
+    out: lib
+```
+
+Server modules are generated into the same directory structure as the protobuf definitions, with `.server.pb.ex` suffix.
+
+### Basic Service Implementation
+
+For more realistic applications that require dependencies like database connections, implement handlers 
+with proper dependency injection:
+
+```elixir
+# lib/helloworld/greeter/server/say_hello_handler.ex
+defmodule Helloworld.Greeter.Server.SayHelloHandler do
+  def handle_message(request, _stream) do
+    # Your business logic with dependencies
+    case MyApp.Users.get_user_by_name(request.name) do
+      {:ok, user} -> 
+        reply = %Helloworld.HelloReply{message: "Hello #{user.display_name}!"}
+        {:ok, reply}
+      {:error, :not_found} ->
+        raise GRPC.RPCError, status: :not_found, message: "User not found"
+    end
+  end
+end
+
+# lib/helloworld/greeter/server/say_goodbye_handler.ex
+defmodule Helloworld.Greeter.Server.SayGoodbyeHandler do  
+  def handle_message(request, _stream) do
+    case MyApp.Users.log_goodbye(request.name) do
+      :ok ->
+        reply = %Helloworld.GoodbyeReply{message: "Goodbye #{request.name}!"}
+        {:ok, reply}
+      {:error, reason} ->
+        raise GRPC.RPCError, status: :internal, message: "Failed to log goodbye: #{reason}"
+    end
+  end
+end
+```
+
+## Explanations
+
+### Overview
+
+This plugin generates gRPC server modules that provide a convenient way to organize handler functions using 
+Elixir's `defdelegate` pattern. **This plugin requires `protoc-gen-elixir` to function** - it generates 
+server modules that reference the protobuf message and service definitions created by the standard Elixir 
+protobuf plugin.
+
+### Features
+
+- **Handler Delegation**: Uses `defdelegate` to separate transport concerns from business logic
+- **Clean Organization**: Each RPC method gets its own dedicated handler module  
+- **Streaming Support**: Handles all gRPC method types automatically
+- **Package Structure**: Maintains protobuf package hierarchy in generated modules