Name changes & enhancements for custom plugin

Author: ryapric

protobuf-grpc/Makefile

@@ -20,7 +20,7 @@ gen:
 	@make -s -C ./proto gen
 
 gen-custom:
-	@make -s -C ./protoc-gen-list-messages gen
+	@make -s -C ./proto gen-custom
 
 # Wrappers for running clients & servers of each language
 server-go:

protobuf-grpc/pb/echo/v1/echo_bash.pb.sh

@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+#################################################
+# Code generated by protoc-gen-bash. DO NOT EDIT.
+#
+# source file: echo/v1/echo.proto
+#################################################
+
+printf 'The messages defined in the provided proto file(s) are:\n'
+
+printf '
+  echo.v1.EchoRequest (fields: msg:string)
+  echo.v1.EchoResponse (fields: msg:string)
+'

protobuf-grpc/pb/employees/v1/employees_bash.pb.sh

@@ -0,0 +1,18 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+#################################################
+# Code generated by protoc-gen-bash. DO NOT EDIT.
+#
+# source file: employees/v1/employees.proto
+#################################################
+
+printf 'The messages defined in the provided proto file(s) are:\n'
+
+printf '
+  employees.v1.GetEmployeeRequest (fields: short_name:string)
+  employees.v1.GetEmployeeResponse (fields: employee:message)
+  employees.v1.GetEmployeeResponse.Employee (fields: id:int64, full_name:string, birthday:string)
+  employees.v1.ListEmployeesRequest (fields: None)
+  employees.v1.ListEmployeesResponse (fields: short_names:repeated_string)
+'

protobuf-grpc/proto/Makefile

@@ -20,7 +20,11 @@ pyvenv = source ../venv/bin/activate
 
 get-proto-deps:
 	@mkdir -p /tmp/proto-deps
-	@for dep in $(proto_deps_sources) ; do git clone --depth=1 https://"$${dep}" $(proto_deps_rootdir)/"$${dep}" || true ; done
+	@for dep in $(proto_deps_sources) ; do \
+		if [[ ! -d $(proto_deps_rootdir)/"$${dep}" ]] ; then \
+			git clone --depth=1 https://"$${dep}" $(proto_deps_rootdir)/"$${dep}" || true ; \
+		fi ; \
+	done
 
 ensure-outdir:
 	@mkdir -p $(outdir)
@@ -30,7 +34,7 @@ ensure-outdir:
 #
 # Most lang/output code can be generated directly by a single call to protoc
 # with available plugins ...
-gen: ensure-outdir
+gen: get-proto-deps ensure-outdir
 	@printf 'Generating protobuf code...\n'
 	@$(pyvenv) && \
 	protoc \
@@ -72,3 +76,17 @@ gen: ensure-outdir
 # our tree set up that way
 	@printf 'Fixing Python import statements...\n'
 	@find $(outdir) -type f -name '*.py' | xargs -I{} sed -E -i 's/^from .*\.v[0-9]+ import (.*)/from . import \1/g' {}
+
+# These targets show that you can use a custom-built protoc plugin to generate
+# code from proto defs however you want!
+build:
+	@make -s -C ../protoc-gen-bash build
+
+gen-custom: get-proto-deps ensure-outdir build
+	@printf 'Generating code using custom protoc plugin...\n'
+	@protoc \
+		--plugin=../protoc-gen-bash/build/protoc-gen-bash \
+		$(proto_deps_import_flags) \
+		--bash_out=$(outdir) \
+		--bash_opt=paths=source_relative \
+		$(proto_files)

protobuf-grpc/proto/employees/v1/employees.proto

@@ -33,23 +33,23 @@ service EmployeesService {
   }
 }
 
-// Defines the record structure for each employee
-message Employee {
-  // Employee ID number
-  int64 id = 1;
-  // Employee full name
-  string full_name = 2;
-  // Employee birthday, in RFC 3339 date format
-  string birthday = 3;
-}
-
 // For calling GetEmployee
 message GetEmployeeRequest {
   string short_name = 1;
 }
 
 // Response from the GetEmployee call
 message GetEmployeeResponse {
+  // Defines the record structure for each employee
+  message Employee {
+    // Employee ID number
+    int64 id = 1;
+    // Employee full name
+    string full_name = 2;
+    // Employee birthday, in RFC 3339 date format
+    string birthday = 3;
+  }
+
   // Contains Employee record details
   Employee employee = 1;
 }

…grpc/protoc-gen-list-messages/.gitignore protobuf-grpc/protoc-gen-bash/.gitignoreprotobuf-grpc/protoc-gen-list-messages/.gitignore renamed to protobuf-grpc/protoc-gen-bash/.gitignore protobuf-grpc/protoc-gen-list-messages/.gitignore renamed to protobuf-grpc/protoc-gen-bash/.gitignore

@@ -0,0 +1,3 @@
+.PHONY: build
+build:
+	@go build -o ./build/ .

protobuf-grpc/protoc-gen-bash/Makefile

@@ -0,0 +1,69 @@
+package main
+
+import (
+	"strings"
+
+	"google.golang.org/protobuf/compiler/protogen"
+)
+
+func main() {
+	opts := protogen.Options{}
+	opts.Run(func(gen *protogen.Plugin) error {
+		for _, f := range gen.Files {
+			if f.Generate {
+				generateFile(gen, f)
+			}
+		}
+		return nil
+	})
+}
+
+func generateFile(gen *protogen.Plugin, file *protogen.File) {
+	filename := file.GeneratedFilenamePrefix + "_bash.pb.sh"
+	g := gen.NewGeneratedFile(filename, file.GoImportPath)
+	g.P("#!/usr/bin/env bash")
+	g.P("set -euo pipefail")
+	g.P()
+	g.P("#################################################")
+	g.P("# Code generated by protoc-gen-bash. DO NOT EDIT.")
+	g.P("#")
+	g.P("# source file: ", *file.Proto.Name)
+	g.P("#################################################")
+	g.P()
+	g.P(`printf 'The messages defined in the provided proto file(s) are:\n'`)
+	g.P()
+	g.P(`printf '`)
+	printMessages(g, file.Messages)
+	g.P(`'`)
+}
+
+// printMessages traverses nested Messages recursively and prints their
+// FullNames along with their Field information
+func printMessages(g *protogen.GeneratedFile, msgs []*protogen.Message) {
+	for _, msg := range msgs {
+		var fields []string
+		for _, field := range msg.Fields {
+			fieldName := string(field.Desc.Name())
+
+			// Cardinality tells us e.g. if a field is repeated
+			fieldCardinality := field.Desc.Cardinality().String()
+			if fieldCardinality != "repeated" {
+				fieldCardinality = ""
+			} else {
+				fieldCardinality += "_"
+			}
+
+			fieldType := field.Desc.Kind().String()
+			fields = append(fields, fieldName+":"+fieldCardinality+fieldType)
+		}
+		// In case a message has no fields, like ListEmployeesRequest
+		if len(fields) == 0 {
+			fields = []string{"None"}
+		}
+
+		g.P(`  `, msg.Desc.FullName(), " (fields: ", strings.Join(fields, ", "), ")")
+		if len(msg.Messages) > 0 {
+			printMessages(g, msg.Messages)
+		}
+	}
+}