add a startup hook

common/common.go

@@ -312,6 +312,11 @@ type Configuration struct {
 	// If proxy protocol is set to 2 and we receive a proxy header from an IP that is not in the list then the
 	// connection will be rejected.
 	ProxyAllowed []string `json:"proxy_allowed" mapstructure:"proxy_allowed"`
+	// Absolute path to an external program or an HTTP URL to invoke as soon as SFTPGo starts.
+	// If you define an HTTP URL it will be invoked using a `GET` request.
+	// Please note that SFTPGo services may not yet be available when this hook is run.
+	// Leave empty do disable.
+	StartupHook string `json:"startup_hook" mapstructure:"startup_hook"`
 	// Absolute path to an external program or an HTTP URL to invoke after a user connects
 	// and before he tries to login. It allows you to reject the connection based on the source
 	// ip address. Leave empty do disable.
@@ -363,6 +368,43 @@ func (c *Configuration) GetProxyListener(listener net.Listener) (*proxyproto.Lis
 	return proxyListener, nil
 }
 
+// ExecuteStartupHook runs the startup hook if defined
+func (c *Configuration) ExecuteStartupHook() error {
+	if c.StartupHook == "" {
+		return nil
+	}
+	if strings.HasPrefix(c.StartupHook, "http") {
+		var url *url.URL
+		url, err := url.Parse(c.StartupHook)
+		if err != nil {
+			logger.Warn(logSender, "", "Invalid startup hook %#v: %v", c.StartupHook, err)
+			return err
+		}
+		startTime := time.Now()
+		httpClient := httpclient.GetRetraybleHTTPClient()
+		resp, err := httpClient.Get(url.String())
+		if err != nil {
+			logger.Warn(logSender, "", "Error executing startup hook: %v", err)
+			return err
+		}
+		defer resp.Body.Close()
+		logger.Debug(logSender, "", "Startup hook executed, elapsed: %v, response code: %v", time.Since(startTime), resp.StatusCode)
+		return nil
+	}
+	if !filepath.IsAbs(c.StartupHook) {
+		err := fmt.Errorf("invalid startup hook %#v", c.StartupHook)
+		logger.Warn(logSender, "", "Invalid startup hook %#v", c.StartupHook)
+		return err
+	}
+	startTime := time.Now()
+	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
+	defer cancel()
+	cmd := exec.CommandContext(ctx, c.StartupHook)
+	err := cmd.Run()
+	logger.Debug(logSender, "", "Startup hook executed, elapsed: %v, error: %v", time.Since(startTime), err)
+	return nil
+}
+
 // ExecutePostConnectHook executes the post connect hook if defined
 func (c *Configuration) ExecutePostConnectHook(ipAddr, protocol string) error {
 	if c.PostConnectHook == "" {

common/common_test.go

@@ -449,6 +449,33 @@ func TestProxyProtocolVersion(t *testing.T) {
 	assert.Error(t, err)
 }
 
+func TestStartupHook(t *testing.T) {
+	Config.StartupHook = ""
+
+	assert.NoError(t, Config.ExecuteStartupHook())
+
+	Config.StartupHook = "http://foo\x7f.com/startup"
+	assert.Error(t, Config.ExecuteStartupHook())
+
+	Config.StartupHook = "http://invalid:5678/"
+	assert.Error(t, Config.ExecuteStartupHook())
+
+	Config.StartupHook = fmt.Sprintf("http://%v", httpAddr)
+	assert.NoError(t, Config.ExecuteStartupHook())
+
+	Config.StartupHook = "invalidhook"
+	assert.Error(t, Config.ExecuteStartupHook())
+
+	if runtime.GOOS != osWindows {
+		hookCmd, err := exec.LookPath("true")
+		assert.NoError(t, err)
+		Config.StartupHook = hookCmd
+		assert.NoError(t, Config.ExecuteStartupHook())
+	}
+
+	Config.StartupHook = ""
+}
+
 func TestPostConnectHook(t *testing.T) {
 	Config.PostConnectHook = ""
 

docs/full-configuration.md

@@ -62,6 +62,7 @@ The configuration file contains the following sections:
   - `proxy_allowed`, List of IP addresses and IP ranges allowed to send the proxy header:
     - If `proxy_protocol` is set to 1 and we receive a proxy header from an IP that is not in the list then the connection will be accepted and the header will be ignored
     - If `proxy_protocol` is set to 2 and we receive a proxy header from an IP that is not in the list then the connection will be rejected
+  - `startup_hook`, string. Absolute path to an external program or an HTTP URL to invoke as soon as SFTPGo starts. If you define an HTTP URL it will be invoked using a `GET` request. Please note that SFTPGo services may not yet be available when this hook is run. Leave empty do disable
   - `post_connect_hook`, string. Absolute path to the command to execute or HTTP URL to notify. See [Post connect hook](./post-connect-hook.md) for more details. Leave empty to disable
   - `max_total_connections`, integer. Maximum number of concurrent client connections. 0 means unlimited
   - `defender`, struct containing the defender configuration. See [Defender](./defender.md) for more details.

service/service.go

@@ -131,6 +131,7 @@ func (s *Service) Start() error {
 	}
 
 	s.startServices()
+	go common.Config.ExecuteStartupHook() //nolint:errcheck
 
 	return nil
 }

sftpgo.json

@@ -9,6 +9,7 @@
     "setstat_mode": 0,
     "proxy_protocol": 0,
     "proxy_allowed": [],
+    "startup_hook": "",
     "post_connect_hook": "",
     "max_total_connections": 0,
     "defender": {