removed EngineService from protos/engine/engine.proto

Author: asmyasnikov

Makefile

@@ -53,7 +53,6 @@ proto:
 proto-engine-plugin:
 	protoc -I. \
 		--go_out=. --go_opt=module=github.com/sqlc-dev/sqlc --go_opt=Mprotos/engine/engine.proto=github.com/sqlc-dev/sqlc/pkg/engine \
-		--go-grpc_out=. --go-grpc_opt=module=github.com/sqlc-dev/sqlc --go-grpc_opt=Mprotos/engine/engine.proto=github.com/sqlc-dev/sqlc/pkg/engine \
 		protos/engine/engine.proto
 
 remote-proto:

docs/guides/engine-plugins.md

@@ -194,7 +194,7 @@ The definition lives in `protos/engine/engine.proto` (generated Go in `pkg/engin
 
 ## Example
 
-The protocol and Go SDK are in this repository: `protos/engine/engine.proto` and `pkg/engine/` (including `sdk.go` with `engine.Run` and `engine.Handler`). Use them to build a binary that implements the Parse RPC; register it under `engines` in sqlc.yaml as shown above.
+The protocol and Go SDK are in this repository: `protos/engine/engine.proto` and `pkg/engine/` (including `sdk.go` with `engine.Run` and `engine.Handler`). Use them to build a binary that handles the `parse` subcommand (stdin: `ParseRequest`, stdout: `ParseResponse`); register it under `engines` in sqlc.yaml as shown above.
 
 ## Architecture
 

pkg/engine/engine.pb.go

@@ -12,7 +12,7 @@
 // The Protocol Buffer schema is published at buf.build/sqlc/sqlc and ensures
 // binary compatibility between sqlc and plugins.
 //
-// # Generating engine.pb.go and engine_grpc.pb.go
+// # Generating engine.pb.go
 //
 // Run from the repository root:
 //
@@ -22,7 +22,6 @@
 //
 //	protoc -I. \
 //		--go_out=. --go_opt=module=github.com/sqlc-dev/sqlc --go_opt=Mprotos/engine/engine.proto=github.com/sqlc-dev/sqlc/pkg/engine \
-//		--go-grpc_out=. --go-grpc_opt=module=github.com/sqlc-dev/sqlc --go-grpc_opt=Mprotos/engine/engine.proto=github.com/sqlc-dev/sqlc/pkg/engine \
 //		protos/engine/engine.proto
 //
 // Example plugin:

pkg/engine/engine_grpc.pb.go

@@ -2,15 +2,10 @@ syntax = "proto3";
 
 package engine;
 
-// EngineService defines the interface for database engine plugins.
-// Engine plugins are responsible for parsing SQL statements and extracting
-// information about parameters and result columns.
-service EngineService {
-  // Parse parses SQL statements and returns the processed SQL along with
-  // information about parameters and result columns.
-  rpc Parse (ParseRequest) returns (ParseResponse);
-}
-
+// Database engine plugins are subprocesses: sqlc runs e.g. `my-engine-plugin parse`,
+// writes a serialized ParseRequest to stdin, reads a serialized ParseResponse from stdout.
+// There is no gRPC on the wire — only these protobuf messages.
+//
 // ParseRequest contains the SQL to parse and either schema or connection parameters.
 message ParseRequest {
   // The SQL query text to parse.