gexe

Project gexe

Script-like OS interaction wrapped in the security and type safety of the Go programming language!

The goal of project gexe is to make it dead simple to write code that interacts with the OS (and/or other components) with the type safety of the Go programming language.

NOTE: this project got renamed from Echo to Gexe (see Project Name Change)

What can you do with gexe?

• Parse and execute OS commands provided as plain and clear text as you would in a shell.
• Support for variable expansion in command string (i.e. gexe.Run("echo $HOME"))
• Get process information (i.e. PID, status, exit code, etc)
• Stream data from stdout while process is executing
• Get program information (i.e. args, binary name, working dir, etc)
• Easily read file content into different targets (string, bytes, io.Writer, etc)
• Easily write file content from different sources (i.e. string, bytes, io.Reader, etc)
• Integrate with your shell script using go run

Using gexe

Get the package

go get github.com/vladimirvivien/gexe

Run a process

The following executes command echo "Hello World!" and prints the result:

fmt.Println(gexe.Run(`echo "Hello World!"`))

Alternatively, you can create your own gexe session for more control and error hanlding:

g := gexe.New()
proc := g.RunProc(`echo "Hello World"`)
if proc.Err() != nil {
    fmt.Println(proc.Err())
    os.Exit(proc.ExitCode())    
}
fmt.Println(proc.Result())

Examples

Find more examples here!

Building project $gexe with gexe

This example shows how gexe can be used to build Go project binaries for multiple platforms and OSes. Note the followings:

• The command string is naturally expressed as you would in a shell.
• The use of variable expansion in the commands.

func main() {
	for _, arch := range []string{"amd64"} {
		for _, opsys := range []string{"darwin", "linux"} {
			gexe.SetVar("arch", arch).SetVar("os", opsys)
			gexe.SetVar("binpath", fmt.Sprintf("build/%s/%s/mybinary", arch, opsys))
			result := gexe.Envs("CGO_ENABLED=0 GOOS=$os GOARCH=$arch").Run("go build -o $binpath .")
			if result != "" {
				fmt.Printf("Build for %s/%s failed: %s\n", arch, opsys, result)
				os.Exit(1)
			}
			fmt.Printf("Build %s/%s: %s OK\n", arch, opsys, echo.Eval("$binpath"))
		}
	}
}

See ./examples/build/main.go

Long-running process

This example shows how gexe can be used to launch a long-running process and stream its output. The code invokes the ping command, streams its output, displays the result, and then kills the process after 5 seconds.

func main() {
	execTime := time.Second * 5
	fmt.Println("ping golang.org...")

	p := gexe.StartProc("ping golang.org")

	if p.Err() != nil {
		fmt.Println("ping failed:", p.Err())
		os.Exit(1)
	}

	go func() {
		if _, err := io.Copy(os.Stdout, p.StdOut()); err != nil {
			fmt.Println(err)
			os.Exit(1)
		}
	}()

	<-time.After(execTime)
	p.Kill()
	fmt.Printf("Pinged golang.org for %s\n", execTime)
}

Using a shell

This example uses the git command to print logs and commit info by using /bin/sh to start a shell for command piping:

func main() {
	cmd := `/bin/sh -c "git log --reverse --abbrev-commit --pretty=oneline | cut -d ' ' -f1"`
	for _, p := range strings.Split(gexe.Run(cmd), "\n") {
		gexe.SetVar("patch", p)
		cmd := `/bin/sh -c "git show --abbrev-commit -s --pretty=format:'%h %s (%an) %n' ${patch}"`
		fmt.Println(gexe.Run(cmd))
	}
}

Project Name Change

Originally this project was named echo. However, another Go project by that name has gotten really popular. So this project was renamed gexe (pronounced Jesse).

License

MIT