added configuration checkpoint

docs/manual/kinds/srl.md

@@ -151,6 +151,8 @@ Additional configurations that containerlab adds on top of the factory config:
 * enabling gNMI/JSON-RPC
 * creating tls server certificate
 
+A configuration checkpoint named `clab-initial` is generated by containerlab once default and user-provided configs are applied. The checkpoint may be used to quickly revert configuration changes made by a user to a state that was present after the node was started.
+
 #### User defined startup config
 
 It is possible to make SR Linux nodes boot up with a user-defined config instead of a built-in one. With a [`startup-config`](../nodes.md#startup-config) property of the node/kind a user sets the path to the local config file that will be used as a startup config.

nodes/srl/srl.go

@@ -295,7 +295,11 @@ func (s *srl) PostDeploy(ctx context.Context, params *nodes.PostDeployParams) er
 		return err
 	}
 
-	return s.addOverlayCLIConfig(ctx)
+	if err := s.addOverlayCLIConfig(ctx); err != nil {
+		return err
+	}
+
+	return s.generateCheckpoint(ctx)
 }
 
 func (s *srl) SaveConfig(ctx context.Context) error {
@@ -570,6 +574,26 @@ func (s *srl) addOverlayCLIConfig(ctx context.Context) error {
 	return nil
 }
 
+func (s *srl) generateCheckpoint(ctx context.Context) error {
+	cmd, err := exec.NewExecCmdFromString(`bash -c 'sr_cli /tools system configuration generate-checkpoint name clab-initial comment \"set by containerlab\"'`)
+	if err != nil {
+		return err
+	}
+
+	execResult, err := s.RunExec(ctx, cmd)
+	if err != nil {
+		return err
+	}
+
+	if len(execResult.GetStdErrString()) != 0 {
+		return fmt.Errorf("%w:%s", nodes.ErrCommandExecError, execResult.GetStdErrString())
+	}
+
+	log.Debugf("node %s. stdout: %s, stderr: %s", s.Cfg.ShortName, execResult.GetStdOutString(), execResult.GetStdErrString())
+
+	return nil
+}
+
 // populateHosts adds container hostnames for other nodes of a lab to SR Linux /etc/hosts file
 // to mitigate the fact that srlinux uses non default netns for management and thus
 // can't leverage docker DNS service.