test_respawn.py

import re
import subprocess
import time

import pytest

from unit.applications.lang.python import ApplicationPython

prerequisites = {'modules': {'python': 'any'}}

client = ApplicationPython()

PATTERN_ROUTER = 'unit: router'
PATTERN_CONTROLLER = 'unit: controller'


@pytest.fixture(autouse=True)
def setup_method_fixture(temp_dir):
    client.app_name = f'app-{temp_dir.split("/")[-1]}'

    client.load('empty', client.app_name)

    assert 'success' in client.conf(
        '1', f'applications/{client.app_name}/processes'
    )


def pid_by_name(name, ppid):
    output = subprocess.check_output(['ps', 'ax', '-O', 'ppid']).decode()
    m = re.search(fr'\s*(\d+)\s*{ppid}.*{name}', output)
    return None if m is None else m.group(1)


def kill_pids(*pids):
    subprocess.call(['kill', '-9', *pids])


def wait_for_process(process, unit_pid):
    for _ in range(50):
        found = pid_by_name(process, unit_pid)

        if found is not None:
            break

        time.sleep(0.1)

    return found


def find_proc(name, ppid, ps_output):
    return re.findall(fr'{ppid}.*{name}', ps_output)


def smoke_test(unit_pid):
    for _ in range(10):
        r = client.conf('1', f'applications/{client.app_name}/processes')

        if 'success' in r:
            break

        time.sleep(0.1)

    assert 'success' in r
    assert client.get()['status'] == 200

    # Check if the only one router, controller,
    # and application processes running.

    out = subprocess.check_output(['ps', 'ax', '-O', 'ppid']).decode()
    assert len(find_proc(PATTERN_ROUTER, unit_pid, out)) == 1
    assert len(find_proc(PATTERN_CONTROLLER, unit_pid, out)) == 1
    assert len(find_proc(client.app_name, unit_pid, out)) == 1


def test_respawn_router(skip_alert, unit_pid, skip_fds_check):
    skip_fds_check(router=True)
    pid = pid_by_name(PATTERN_ROUTER, unit_pid)

    kill_pids(pid)
    skip_alert(fr'process {pid} exited on signal 9')

    assert wait_for_process(PATTERN_ROUTER, unit_pid) is not None

    smoke_test(unit_pid)


def test_respawn_controller(skip_alert, unit_pid, skip_fds_check):
    skip_fds_check(controller=True)
    pid = pid_by_name(PATTERN_CONTROLLER, unit_pid)

    kill_pids(pid)
    skip_alert(fr'process {pid} exited on signal 9')

    assert wait_for_process(PATTERN_CONTROLLER, unit_pid) is not None

    assert client.get()['status'] == 200

    smoke_test(unit_pid)


def test_respawn_application(skip_alert, unit_pid):
    pid = pid_by_name(client.app_name, unit_pid)

    kill_pids(pid)
    skip_alert(fr'process {pid} exited on signal 9')

    assert wait_for_process(client.app_name, unit_pid) is not None

    smoke_test(unit_pid)