Echo with condition (#241)

* add condition support to echo, see #240

* format tests

* clarify condition limitation

README.md

@@ -478,6 +478,8 @@ example installing curl package if not installed already:
     cond: "! command -v curl"
 ```
 
+currently conditions can be used with `script` and `echo` command types only.
+
 ### Deferred actions (`on_exit`)
 
 Each command may have `on_exit` parameter defined. It allows executing a command on the remote host after the task with all commands is completed. The command is called regardless of the task's exit code.

pkg/runner/commands.go

@@ -346,6 +346,17 @@ func (ec *execCmd) Wait(ctx context.Context) (resp execCmdResp, err error) {
 // Echo prints a message. It enforces the echo command to start with "echo " and adds sudo if needed.
 // It returns the result of the echo command as details string.
 func (ec *execCmd) Echo(ctx context.Context) (resp execCmdResp, err error) {
+	// check the condition if it exists
+	cond, err := ec.checkCondition(ctx)
+	if err != nil {
+		return resp, err
+	}
+	if !cond {
+		resp.details = fmt.Sprintf(" {skip: %s}", ec.cmd.Name)
+		return resp, nil
+	}
+
+	// only proceed with echo if there was no condition or condition passed
 	tmpl := templater{hostAddr: ec.hostAddr, hostName: ec.hostName, task: ec.tsk, command: ec.cmd.Name, env: ec.cmd.Environment}
 	echoCmd := tmpl.apply(ec.cmd.Echo)
 	if !strings.HasPrefix(echoCmd, "echo ") {

pkg/runner/commands_test.go

@@ -347,6 +347,72 @@ func Test_execCmd(t *testing.T) {
 		assert.Equal(t, " {echo: foo welcome back}", resp.details)
 	})
 
+	t.Run("echo command with condition true", func(t *testing.T) {
+		defer os.Remove("/tmp/test.condition")
+		_, err := sess.Run(ctx, "touch /tmp/test.condition", nil)
+		require.NoError(t, err)
+		ec := execCmd{
+			exec: sess,
+			tsk:  &config.Task{Name: "test"},
+			cmd: config.Cmd{
+				Echo:      "welcome back",
+				Name:      "test",
+				Condition: "test -f /tmp/test.condition",
+			},
+		}
+		resp, err := ec.Echo(ctx)
+		require.NoError(t, err)
+		assert.Equal(t, " {echo: welcome back}", resp.details)
+	})
+
+	t.Run("echo command with condition false", func(t *testing.T) {
+		ec := execCmd{
+			exec: sess,
+			tsk:  &config.Task{Name: "test"},
+			cmd: config.Cmd{
+				Echo:      "welcome back",
+				Name:      "test",
+				Condition: "test -f /tmp/nonexistent.condition",
+			},
+		}
+		resp, err := ec.Echo(ctx)
+		require.NoError(t, err)
+		assert.Equal(t, " {skip: test}", resp.details)
+	})
+
+	t.Run("echo command with condition true inverted", func(t *testing.T) {
+		ec := execCmd{
+			exec: sess,
+			tsk:  &config.Task{Name: "test"},
+			cmd: config.Cmd{
+				Echo:      "welcome back",
+				Name:      "test",
+				Condition: "! test -f /tmp/nonexistent.condition",
+			},
+		}
+		resp, err := ec.Echo(ctx)
+		require.NoError(t, err)
+		assert.Equal(t, " {echo: welcome back}", resp.details)
+	})
+
+	t.Run("echo command with condition false inverted", func(t *testing.T) {
+		defer os.Remove("/tmp/test2.condition")
+		_, err := sess.Run(ctx, "touch /tmp/test2.condition", nil)
+		require.NoError(t, err)
+		ec := execCmd{
+			exec: sess,
+			tsk:  &config.Task{Name: "test"},
+			cmd: config.Cmd{
+				Echo:      "welcome back",
+				Name:      "test",
+				Condition: "! test -f /tmp/test2.condition",
+			},
+		}
+		resp, err := ec.Echo(ctx)
+		require.NoError(t, err)
+		assert.Equal(t, " {skip: test}", resp.details)
+	})
+
 	t.Run("sync command", func(t *testing.T) {
 		ec := execCmd{exec: sess, tsk: &config.Task{Name: "test"}, cmd: config.Cmd{Sync: config.SyncInternal{
 			Source: "testdata", Dest: "/tmp/sync.testdata", Exclude: []string{"conf2.yml"}}, Name: "test"}}