feat: add worker install and deploy

internal/installer/install.go

@@ -0,0 +1,225 @@
+package installer
+
+import (
+	"errors"
+	"fmt"
+	"io"
+	"net/url"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"regexp"
+	"strings"
+)
+
+var dockerImagePattern = regexp.MustCompile(`^[A-Za-z0-9][A-Za-z0-9._/:@-]*$`)
+
+const (
+	DefaultURL   = "https://rsmon.ru"
+	DefaultImage = "reg.rsxx.ru/rsmon/rsmon-worker:latest"
+	binaryPath   = "/usr/local/bin/rsmon-worker"
+	envPath      = "/etc/rsmon-worker/worker.env"
+	unitPath     = "/etc/systemd/system/rsmon-worker.service"
+)
+
+const systemdUnit = `[Unit]
+Description=RSMon distributed monitoring worker
+After=network-online.target
+
+[Service]
+Type=simple
+User=root
+EnvironmentFile=/etc/rsmon-worker/worker.env
+ExecStart=/usr/local/bin/rsmon-worker
+Restart=on-failure
+
+[Install]
+WantedBy=multi-user.target
+`
+
+const dockerSystemdUnit = `[Unit]
+Description=RSMon distributed monitoring worker (Docker)
+After=network-online.target docker.service
+Requires=docker.service
+
+[Service]
+Type=simple
+User=root
+ExecStartPre=-docker rm -f rsmon-worker
+ExecStart=docker run --rm --name rsmon-worker --network host --cap-add NET_RAW --env-file /etc/rsmon-worker/worker.env -v rsmon-worker-data:/var/lib/rsmon-worker %s
+ExecStop=docker stop rsmon-worker
+Restart=on-failure
+
+[Install]
+WantedBy=multi-user.target
+`
+
+type InstallOptions struct {
+	Binary  string
+	EnvFile string
+	Token   string
+	URL     string
+	Docker  bool
+	Image   string
+	NoStart bool
+}
+
+func Install(opts InstallOptions) error {
+	if os.Geteuid() != 0 {
+		return errors.New("install must be run as root")
+	}
+	if opts.URL == "" {
+		opts.URL = DefaultURL
+	}
+	if err := ValidateURL(opts.URL); err != nil {
+		return err
+	}
+	if opts.EnvFile == "" {
+		if err := ValidateToken(opts.Token); err != nil {
+			return err
+		}
+	}
+	if opts.Image == "" {
+		opts.Image = DefaultImage
+	}
+	if opts.Docker {
+		if err := ValidateImage(opts.Image); err != nil {
+			return err
+		}
+	} else if opts.Binary == "" {
+		var err error
+		opts.Binary, err = os.Executable()
+		if err != nil {
+			return fmt.Errorf("locate worker executable: %w", err)
+		}
+	}
+	unit := systemdUnit
+	if opts.Docker {
+		if _, err := exec.LookPath("docker"); err != nil {
+			return errors.New("docker is required for --docker installation")
+		}
+		if err := command("docker", "pull", opts.Image); err != nil {
+			return err
+		}
+		unit = DockerUnit(opts.Image)
+	} else if err := copyAtomic(opts.Binary, binaryPath, 0755); err != nil {
+		return fmt.Errorf("install binary: %w", err)
+	}
+	if err := writeAtomic(unitPath, []byte(unit), 0644); err != nil {
+		return fmt.Errorf("install systemd unit: %w", err)
+	}
+	if opts.EnvFile != "" {
+		if err := copyAtomic(opts.EnvFile, envPath, 0600); err != nil {
+			return fmt.Errorf("install environment: %w", err)
+		}
+	} else {
+		if err := writeAtomic(envPath, Environment(opts.URL, opts.Token), 0600); err != nil {
+			return fmt.Errorf("install environment: %w", err)
+		}
+	}
+	if err := command("systemctl", "daemon-reload"); err != nil {
+		return err
+	}
+	if err := command("systemctl", "enable", "rsmon-worker.service"); err != nil {
+		return err
+	}
+	if !opts.NoStart {
+		if err := command("systemctl", "restart", "rsmon-worker.service"); err != nil {
+			return err
+		}
+		if err := command("systemctl", "is-active", "--quiet", "rsmon-worker.service"); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func ValidateURL(raw string) error {
+	if strings.ContainsAny(raw, "\r\n") {
+		return fmt.Errorf("server URL must be an absolute HTTP(S) URL")
+	}
+	u, err := url.Parse(raw)
+	if err != nil || u.Host == "" || (u.Scheme != "https" && u.Scheme != "http") {
+		return fmt.Errorf("server URL must be an absolute HTTP(S) URL")
+	}
+	return nil
+}
+
+func Environment(serverURL, token string) []byte {
+	return []byte("RSMON_URL=" + serverURL + "\nRSMON_TOKEN=" + token + "\nWORKER_HOST=127.0.0.1\n")
+}
+
+func ValidateToken(token string) error {
+	if strings.TrimSpace(token) == "" || strings.ContainsAny(token, "\r\n") {
+		return errors.New("worker token must be non-empty and contain no newlines")
+	}
+	return nil
+}
+
+func ValidateImage(image string) error {
+	if !dockerImagePattern.MatchString(image) {
+		return errors.New("Docker image must be one non-option argument")
+	}
+	return nil
+}
+
+func DockerUnit(image string) string {
+	return fmt.Sprintf(dockerSystemdUnit, image)
+}
+
+func copyAtomic(src, dst string, mode os.FileMode) error {
+	in, err := os.Open(src)
+	if err != nil {
+		return err
+	}
+	defer in.Close()
+	return atomicFile(dst, mode, func(out *os.File) error {
+		_, err := io.Copy(out, in)
+		return err
+	})
+}
+
+func writeAtomic(dst string, data []byte, mode os.FileMode) error {
+	return atomicFile(dst, mode, func(out *os.File) error {
+		_, err := out.Write(data)
+		return err
+	})
+}
+
+func atomicFile(dst string, mode os.FileMode, write func(*os.File) error) error {
+	if err := os.MkdirAll(filepath.Dir(dst), 0755); err != nil {
+		return err
+	}
+	tmp, err := os.CreateTemp(filepath.Dir(dst), ".rsmon-worker-*")
+	if err != nil {
+		return err
+	}
+	name := tmp.Name()
+	defer os.Remove(name)
+	if err := tmp.Chmod(mode); err != nil {
+		tmp.Close()
+		return err
+	}
+	if err := write(tmp); err != nil {
+		tmp.Close()
+		return err
+	}
+	if err := tmp.Sync(); err != nil {
+		tmp.Close()
+		return err
+	}
+	if err := tmp.Close(); err != nil {
+		return err
+	}
+	return os.Rename(name, dst)
+}
+
+func command(name string, args ...string) error {
+	cmd := exec.Command(name, args...)
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+	if err := cmd.Run(); err != nil {
+		return fmt.Errorf("%s failed: %w", name, err)
+	}
+	return nil
+}