TCM: Add tt tcm status/stop

[AlexandrLitkevich]

What has been done? Why? What problem is being solved?

I didn't forget about (remove if it is not applicable):

• Well-written commit messages (see documentation how to write a commit message)
• Don't forget about TarantoolBot in a commit message (see example)
• Tests (see documentation for a testing package)
• Changelog (see documentation for changelog format)
• Documentation (see documentation for documentation style guide)

Related issues:

Closes #TNTP-1992
Closes #TNTP-1993

[oleg-jukovec]

It is not implemented in the PR. Looks like a rebase artifacts or something like that.

[AlexandrLitkevich]

Done

[oleg-jukovec]

Please, add a separate commit with a format update if you want to change a formatting of the whole file.

[AlexandrLitkevich]

I corrected it, but one line still looks like a new line for some unknown reason.

[oleg-jukovec]

We don't need the suffix since we have a file extension that told us that it is a pid file.

Suggested change

	tcmPidFile = "tcmPidFile.pid"
	watchdogPidFile = "watchdogPidFile.pid"
	tcmPidFile = "tcm.pid"
	watchdogPidFile = "watchdog.pid"

[AlexandrLitkevich]

done

[oleg-jukovec]

We need a test for the call.

[AlexandrLitkevich]

Done

[oleg-jukovec]

This is a common code style in go. Please fix comments below.

Suggested change

	// Command for launching and managing the child process.
	cmd *exec.Cmd
	// Timeout before restarting a failed process.
	restartTimeout time.Duration
	// Atomic flag for graceful shutdown.
	shouldStop atomic.Bool
	// cmd is a command for launching and managing the child process.
	cmd *exec.Cmd
	// restartTimeout is a timeout before restarting a failed process.
	restartTimeout time.Duration
	// shouldStop is an atomic flag for graceful shutdown.
	shouldStop atomic.Bool

[AlexandrLitkevich]

Done

[oleg-jukovec]

Please, rewrite tests without an additional nested level.

Suggested change

	// TestWatchdog_StartStop tests that the watchdog starts a process, creates a PID
	// file, and stops the process when asked to.
	func TestWatchdog_StartStop(t *testing.T) {
	t.Run("successful start and graceful stop", func(t *testing.T) {
	wd := NewWatchdog("test.pid", "wd.pid", 100*time.Millisecond)
	t.Cleanup(func() {
	os.Remove("test.pid")
	os.Remove("wd.pid")
	})
	// Mock command that will sleep for 1 second.
	cmd := exec.Command("sleep", "1")
	errChan := make(chan error, 1)
	go func() {
	errChan <- wd.Start(cmd.Path, cmd.Args[1:]...)
	}()
	// Wait for process to start.
	time.Sleep(200 * time.Millisecond)
	// Verify process is running.
	wd.cmdMutex.Lock()
	require.NotNil(t, wd.cmd)
	require.NotNil(t, wd.cmd.Process)
	wd.cmdMutex.Unlock()
	// Stop the watchdog.
	wd.Stop()
	// Verify no errors.
	select {
	case err := <-errChan:
	require.NoError(t, err)
	case <-time.After(500 * time.Millisecond):
	t.Fatal("timeout waiting for Start to return")
	}
	})
	// TestWatchdog_StartStop tests that the watchdog starts a process, creates a PID
	// file, and stops the process when asked to.
	func TestWatchdog_StartStop_successful(t *testing.T) {
	wd := NewWatchdog("test.pid", "wd.pid", 100*time.Millisecond)
	t.Cleanup(func() {
	os.Remove("test.pid")
	os.Remove("wd.pid")
	})
	// Mock command that will sleep for 1 second.
	cmd := exec.Command("sleep", "1")
	errChan := make(chan error, 1)
	go func() {
	errChan <- wd.Start(cmd.Path, cmd.Args[1:]...)
	}()
	// Wait for process to start.
	time.Sleep(200 * time.Millisecond)
	// Verify process is running.
	wd.cmdMutex.Lock()
	require.NotNil(t, wd.cmd)
	require.NotNil(t, wd.cmd.Process)
	wd.cmdMutex.Unlock()
	// Stop the watchdog.
	wd.Stop()
	// Verify no errors.
	select {
	case err := <-errChan:
	require.NoError(t, err)
	case <-time.After(500 * time.Millisecond):
	t.Fatal("timeout waiting for Start to return")
	}
	}

[AlexandrLitkevich]

done

[oleg-jukovec]

The name of the test says that here actually two tests: for start and for stop.

[AlexandrLitkevich]

done