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Go: Running a request through an SSH tunnel
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| package main | |
| import ( | |
| "io" | |
| "io/ioutil" | |
| "log" | |
| "net" | |
| "net/http" | |
| "golang.org/x/crypto/ssh" | |
| ) | |
| const ( | |
| // given the equivalent OpenSSH command: | |
| // ssh -L 9201:my-service.prod.service.private:80 manzanit0@my-bastion.com | |
| jumpServerUser = "manzanit0" | |
| jumpServer = "my-bastion.com:22" | |
| localAddr = "localhost:9201" | |
| remoteAddr = "my-service.prod.service.private:80" | |
| ) | |
| func main() { | |
| authKey := AuthPrivateKeyFile("/Users/manzanit0/.ssh/id_rsa") | |
| clientConfig, err := config(authKey) | |
| if err != nil { | |
| log.Fatalf("failed to create ssh config: %q", err) | |
| } | |
| clientConn, err := ssh.Dial("tcp", jumpServer, clientConfig) | |
| if err != nil { | |
| log.Fatalf("failed to connect to the ssh server: %q", err) | |
| } | |
| go func() { | |
| if err := tunnel(clientConn, localAddr, remoteAddr); err != nil { | |
| log.Fatalf("failed to tunnel traffic: %q", err) | |
| } | |
| }() | |
| resp, err := http.Get("http://" + localAddr + "/health") | |
| if err != nil { | |
| log.Fatalf("failed make request to tunneled server: %q", err) | |
| } | |
| log.Printf("response: %s", resp.Status) | |
| } | |
| func tunnel(conn *ssh.Client, local, remote string) error { | |
| pipe := func(writer, reader net.Conn) { | |
| defer writer.Close() | |
| defer reader.Close() | |
| _, err := io.Copy(writer, reader) | |
| if err != nil { | |
| log.Printf("failed to copy: %s", err) | |
| } | |
| } | |
| listener, err := net.Listen("tcp", local) | |
| if err != nil { | |
| return err | |
| } | |
| log.Printf("listening on %s", local) | |
| for { | |
| here, err := listener.Accept() | |
| if err != nil { | |
| return err | |
| } | |
| go func(here net.Conn) { | |
| there, err := conn.Dial("tcp", remote) | |
| if err != nil { | |
| log.Fatalf("failed to dial to remote: %q", err) | |
| } | |
| go pipe(there, here) | |
| go pipe(here, there) | |
| }(here) | |
| } | |
| } | |
| func config(methods ...ssh.AuthMethod) (*ssh.ClientConfig, error) { | |
| return &ssh.ClientConfig{ | |
| User: jumpServerUser, | |
| Auth: methods, | |
| // you should not pass this option, but for the sake of simplicity | |
| // we use it here | |
| HostKeyCallback: ssh.InsecureIgnoreHostKey(), | |
| }, nil | |
| } | |
| func AuthPrivateKeyFile(file string) ssh.AuthMethod { | |
| buffer, err := ioutil.ReadFile(file) | |
| if err != nil { | |
| return nil | |
| } | |
| key, err := ssh.ParsePrivateKey(buffer) | |
| if err != nil { | |
| return nil | |
| } | |
| return ssh.PublicKeys(key) | |
| } |
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