Repo construction breadcrumbs

Notes from the construction of this repo. (It may be instructive to rebuild a repo like this from scratch.)

Part 1: Setup project, build tools, cli commands

Init module

mkdir grpc-go-demo
cd grpc-go-demo
git init
go mod init github.com/rmorison/grpc-go-demo

Get gitignore, makefiles & build tools

curl https://raw.githubusercontent.com/rmorison/techdocs/main/gitignore-sample --output .gitignore
curl https://raw.githubusercontent.com/rmorison/techdocs/main/build-tech/Makefile.proto.builder --output Makefile
curl https://raw.githubusercontent.com/rmorison/techdocs/main/build-tech/Makefile.proto.tools --output tools/Makefile --create-dirs
curl https://raw.githubusercontent.com/rmorison/techdocs/main/build-tech/tools.proto.go --output tools/tools.go
(cd tools && go mod init github.com/rmorison/grpc-go-demo/tools)

Install Cobra, add cli commands for greeter

go install github.com/spf13/cobra/cobra@latest
cobra init
cobra add greeter
cobra add server -p greeterCmd
cobra add client -p greeterCmd
go run main.go --help
go run main.go greeter --help

Initial commit

git add .
git commit -m 'Genesis: Cobra generated Go program with greeter subcommand, protoc build tools'

Part 2 Get helloworld code

Get and commit helloworld files

curl https://codeload.github.com/grpc/grpc-go/tar.gz/refs/tags/v1.43.0 --output - | tar --wildcards --strip-components=1 -xvzf - \*/helloworld
git add examples
git commit -m 'helloworld example from https://github.com/grpc/grpc-go/tree/master/examples/helloworld'

Build helloworld proto

make distclean tools  # only needed once, force rebuild of toolchain jic
make
ls -l examples/helloworld/helloworld  # should see new timestamps on the go files
git diff  # note the updated codegen of go files

Edit greeter_server and greeter_client source

…so we can import them into our Cobra command files, give each it’s own package name, update the pb path, and change main to exportable names.

diff --git a/examples/helloworld/greeter_client/main.go b/examples/helloworld/greeter_client/main.go
index b27b7da..147031b 100644
--- a/examples/helloworld/greeter_client/main.go
+++ b/examples/helloworld/greeter_client/main.go
@@ -17,7 +17,7 @@
  */

 // Package main implements a client for Greeter service.
-package main
+package greeter_client

 import (
 	"context"
@@ -25,8 +25,8 @@ import (
 	"log"
 	"time"

+	pb "github.com/rmorison/grpc-go-demo/examples/helloworld/helloworld"
 	"google.golang.org/grpc"
-	pb "google.golang.org/grpc/examples/helloworld/helloworld"
 )

 const (
@@ -38,7 +38,7 @@ var (
 	name = flag.String("name", defaultName, "Name to greet")
 )

-func main() {
+func Greet() {
 	flag.Parse()
 	// Set up a connection to the server.
 	conn, err := grpc.Dial(*addr, grpc.WithInsecure())
diff --git a/examples/helloworld/greeter_server/main.go b/examples/helloworld/greeter_server/main.go
index 728bb19..54792e4 100644
--- a/examples/helloworld/greeter_server/main.go
+++ b/examples/helloworld/greeter_server/main.go
@@ -17,7 +17,7 @@
  */

 // Package main implements a server for Greeter service.
-package main
+package greeter_server

 import (
 	"context"
@@ -26,8 +26,8 @@ import (
 	"log"
 	"net"

+	pb "github.com/rmorison/grpc-go-demo/examples/helloworld/helloworld"
 	"google.golang.org/grpc"
-	pb "google.golang.org/grpc/examples/helloworld/helloworld"
 )

 var (
@@ -45,7 +45,7 @@ func (s *server) SayHello(ctx context.Context, in *pb.HelloRequest) (*pb.HelloRe
 	return &pb.HelloReply{Message: "Hello " + in.GetName()}, nil
 }

-func main() {
+func ServeGreetings() {
 	flag.Parse()
 	lis, err := net.Listen("tcp", fmt.Sprintf("localhost:%d", *port))
 	if err != nil {

Update the Cobra server and client commands

diff --git a/cmd/client.go b/cmd/client.go
index 83377af..cfe8bdf 100644
--- a/cmd/client.go
+++ b/cmd/client.go
@@ -5,8 +5,7 @@ Copyright © 2022 NAME HERE <EMAIL ADDRESS>
 package cmd

 import (
-	"fmt"
-
+	"github.com/rmorison/grpc-go-demo/examples/helloworld/greeter_client"
 	"github.com/spf13/cobra"
 )

@@ -21,7 +20,7 @@ Cobra is a CLI library for Go that empowers applications.
 This application is a tool to generate the needed files
 to quickly create a Cobra application.`,
 	Run: func(cmd *cobra.Command, args []string) {
-		fmt.Println("client called")
+		greeter_client.Greet()
 	},
 }

diff --git a/cmd/server.go b/cmd/server.go
index 904d94f..dd2d977 100644
--- a/cmd/server.go
+++ b/cmd/server.go
@@ -5,8 +5,7 @@ Copyright © 2022 NAME HERE <EMAIL ADDRESS>
 package cmd

 import (
-	"fmt"
-
+	"github.com/rmorison/grpc-go-demo/examples/helloworld/greeter_server"
 	"github.com/spf13/cobra"
 )

@@ -21,7 +20,7 @@ Cobra is a CLI library for Go that empowers applications.
 This application is a tool to generate the needed files
 to quickly create a Cobra application.`,
 	Run: func(cmd *cobra.Command, args []string) {
-		fmt.Println("server called")
+		greeter_server.ServeGreetings()
 	},
 }

Run the server

/Projects/rmorison/grpc-go-demo$ go run main.go greeter server
2022/01/03 22:51:41 server listening at 127.0.0.1:50051

Run the client

~/Projects/rmorison/grpc-go-demo$ go run main.go greeter client
2022/01/03 22:48:00 Greeting: Hello world

Check the server

2022/01/03 22:48:00 Received: world