SSH Remote Runner

package main

import (
    "bytes"
    "fmt"
    "io"
    "log"
    "os"
    "time"

    "github.com/pkg/sftp"
    "golang.org/x/crypto/ssh"
)

func main() {
    host := os.Getenv("SSH_HOST")       // e.g., "10.0.1.50"
    user := os.Getenv("SSH_USER")       // e.g., "deploy"
    keyPath := os.Getenv("SSH_KEY")     // e.g., "/home/deploy/.ssh/id_ed25519"

    if host == "" || user == "" || keyPath == "" {
        log.Fatal("set SSH_HOST, SSH_USER, SSH_KEY env vars")
    }

    // Build config
    key, err := os.ReadFile(keyPath)
    if err != nil {
        log.Fatalf("read key: %v", err)
    }
    signer, err := ssh.ParsePrivateKey(key)
    if err != nil {
        log.Fatalf("parse key: %v", err)
    }

    config := &ssh.ClientConfig{
        User:            user,
        Auth:            []ssh.AuthMethod{ssh.PublicKeys(signer)},
        HostKeyCallback: ssh.InsecureIgnoreHostKey(),
        Timeout:         10 * time.Second,
    }

    // Connect
    client, err := ssh.Dial("tcp", host+":22", config)
    if err != nil {
        log.Fatalf("dial: %v", err)
    }
    defer client.Close()
    fmt.Printf("✓ Connected to %s\n", host)

    // Run commands
    commands := []string{
        "hostname",
        "df -h /",
        "uptime",
    }
    for _, cmd := range commands {
        session, err := client.NewSession()
        if err != nil {
            log.Fatalf("session: %v", err)
        }
        var buf bytes.Buffer
        session.Stdout = &buf
        if err := session.Run(cmd); err != nil {
            log.Printf("command %q failed: %v", cmd, err)
        } else {
            fmt.Printf("$ %s\n%s\n", cmd, buf.String())
        }
        session.Close()
    }

    // Upload a file via SFTP
    sftpClient, err := sftp.NewClient(client)
    if err != nil {
        log.Fatalf("sftp: %v", err)
    }
    defer sftpClient.Close()

    configContent := []byte("max_connections: 100\nlog_level: info\n")
    dstFile, err := sftpClient.Create("/tmp/app.conf")
    if err != nil {
        log.Fatalf("create remote file: %v", err)
    }
    if _, err := io.Copy(dstFile, bytes.NewReader(configContent)); err != nil {
        log.Fatalf("write remote file: %v", err)
    }
    dstFile.Close()
    fmt.Println("✓ Uploaded /tmp/app.conf")
}