• 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

#+begin_src bash mkdir grpc-go-demo cd grpc-go-demo git init go mod init github.com/rmorison/grpc-go-demo #+end_src

*** Get gitignore, makefiles & build tools #+begin_src bash 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) #+end_src

*** Install Cobra, add cli commands for greeter

#+begin_src bash 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 #+end_src

*** Initial commit

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

** Part 2 Get helloworld code

*** Get and commit helloworld files

#+begin_src bash 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' #+end_src

*** Build helloworld proto

#+begin_src bash 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 #+end_src

*** 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.

#+begin_src diff 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 { #+end_src

*** Update the Cobra server and client commands

#+begin_src diff 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 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 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()
  

  }, }

#+end_src

*** Run the server

#+begin_src bash /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 #+end_src

*** Run the client

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

*** Check the server

#+begin_src bash 2022/01/03 22:48:00 Received: world #+end_src