Project `gexe`

Package with script-like API for system operation and automation!

The goal of project gexe is to make it simple to write code for system operation and task automation using a script-like API that offers the security and the type safety of the Go programming language (see /examples).

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

What can you do with `gexe`?

Parse and execute OS plain text commands, as you would in a shell.
Support for variable expansion in command string (i.e. gexe.Run("echo $HOME"))
Ability to pipe processes: gexe.Pipe("cat /etc/hosts", "wc -l")
Run processes concurrently: gexe.RunConcur('wget https://example.com/files'; "date")
Get process information (i.e. PID, status, exit code, etc)
Get program information (i.e. args, binary name, working dir, etc)
Easily read and write file content using different sources (string, bytes, io.Writer, 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

heylongdacoder/gexe

Project gexe

What can you do with gexe?

Using gexe