mirror of
https://github.com/ets-labs/python-dependency-injector.git
synced 2024-11-23 10:03:56 +03:00
ae3024588c
* Bump version to 4.3.9: FastAPI example * Reengineer wiring * Add @inject decorator * Add .workspace dir to gitignore * Add generic typing for @inject * Add type cast for @inject * Update movie lister example * Update cli application tutorial * Update demo example * Update wiring docs and examples * Update aiohttp example and tutorial * Update multiple containers example * Update single container example * Update decoupled packages example * Update django example * Update asyncio daemon example and tutorial * Update FastAPI example * Update flask example and tutorial * Update sanic example * Add wiring registry * Add new line to .gitignore * Add @inject to the test samples * Fix flake8 errors
1043 lines
27 KiB
ReStructuredText
1043 lines
27 KiB
ReStructuredText
.. _asyncio-daemon-tutorial:
|
|
|
|
Asyncio daemon tutorial
|
|
=======================
|
|
|
|
.. meta::
|
|
:keywords: Python,asyncio,Daemon,Monitoring,Tutorial,Education,Web,API,REST API,Example,DI,
|
|
Dependency injection,IoC,Inversion of control,Refactoring,Tests,Unit tests,Pytest,
|
|
py.test,docker,docker-compose,backend
|
|
:description: This tutorial shows how to build an asyncio application following the dependency
|
|
injection principle. You will create the monitoring daemon, use docker &
|
|
docker-compose, cover the daemon with the unit test and make some refactoring.
|
|
|
|
This tutorial shows how to build an ``asyncio`` daemon following the dependency injection
|
|
principle.
|
|
|
|
In this tutorial we will use:
|
|
|
|
- Python 3
|
|
- Docker
|
|
- Docker-compose
|
|
|
|
Start from the scratch or jump to the section:
|
|
|
|
.. contents::
|
|
:local:
|
|
:backlinks: none
|
|
|
|
You can find complete project on the
|
|
`Github <https://github.com/ets-labs/python-dependency-injector/tree/master/examples/miniapps/asyncio-daemon>`_.
|
|
|
|
What are we going to build?
|
|
---------------------------
|
|
|
|
We will build a monitoring daemon that monitors web services availability.
|
|
|
|
The daemon will send the requests to the `example.com <http://example.com>`_ and
|
|
`httpbin.org <https://httpbin.org>`_ every couple of seconds. For each successfully completed
|
|
response it will log:
|
|
|
|
- The response code
|
|
- The amount of bytes in the response
|
|
- The time took to complete the response
|
|
|
|
.. image:: asyncio-images/diagram.png
|
|
|
|
Prerequisites
|
|
-------------
|
|
|
|
We will use `Docker <https://www.docker.com/>`_ and
|
|
`docker-compose <https://docs.docker.com/compose/>`_ in this tutorial. Let's check the versions:
|
|
|
|
.. code-block:: bash
|
|
|
|
docker --version
|
|
docker-compose --version
|
|
|
|
The output should look something like:
|
|
|
|
.. code-block:: bash
|
|
|
|
Docker version 19.03.12, build 48a66213fe
|
|
docker-compose version 1.26.2, build eefe0d31
|
|
|
|
.. note::
|
|
|
|
If you don't have ``Docker`` or ``docker-compose`` you need to install them before proceeding.
|
|
Follow these installation guides:
|
|
|
|
- `Install Docker <https://docs.docker.com/get-docker/>`_
|
|
- `Install docker-compose <https://docs.docker.com/compose/install/>`_
|
|
|
|
The prerequisites are satisfied. Let's get started with the project layout.
|
|
|
|
Project layout
|
|
--------------
|
|
|
|
Create the project root folder and set it as a working directory:
|
|
|
|
.. code-block:: bash
|
|
|
|
mkdir asyncio-daemon-tutorial
|
|
cd asyncio-daemon-tutorial
|
|
|
|
Now we need to create the initial project structure. Create the files and folders following next
|
|
layout. All files should be empty for now. We will fill them later.
|
|
|
|
Initial project layout:
|
|
|
|
.. code-block:: bash
|
|
|
|
./
|
|
├── monitoringdaemon/
|
|
│ ├── __init__.py
|
|
│ ├── __main__.py
|
|
│ └── containers.py
|
|
├── config.yml
|
|
├── docker-compose.yml
|
|
├── Dockerfile
|
|
└── requirements.txt
|
|
|
|
Initial project layout is ready. We will extend it in the next sections.
|
|
|
|
Let's proceed to the environment preparation.
|
|
|
|
Prepare the environment
|
|
-----------------------
|
|
|
|
In this section we are going to prepare the environment for running our daemon.
|
|
|
|
First we need to specify the project requirements. We will use next packages:
|
|
|
|
- ``dependency-injector`` - the dependency injection framework
|
|
- ``aiohttp`` - the web framework (we need only http client)
|
|
- ``pyyaml`` - the YAML files parsing library, used for the reading of the configuration files
|
|
- ``pytest`` - the test framework
|
|
- ``pytest-asyncio`` - the helper library for the testing of the ``asyncio`` application
|
|
- ``pytest-cov`` - the helper library for measuring the test coverage
|
|
|
|
Put next lines into the ``requirements.txt`` file:
|
|
|
|
.. code-block:: bash
|
|
|
|
dependency-injector
|
|
aiohttp
|
|
pyyaml
|
|
pytest
|
|
pytest-asyncio
|
|
pytest-cov
|
|
|
|
Second, we need to create the ``Dockerfile``. It will describe the daemon's build process and
|
|
specify how to run it. We will use ``python:3.8-buster`` as a base image.
|
|
|
|
Put next lines into the ``Dockerfile`` file:
|
|
|
|
.. code-block:: bash
|
|
|
|
FROM python:3.8-buster
|
|
|
|
ENV PYTHONUNBUFFERED=1
|
|
|
|
WORKDIR /code
|
|
COPY . /code/
|
|
|
|
RUN apt-get install openssl \
|
|
&& pip install --upgrade pip \
|
|
&& pip install -r requirements.txt \
|
|
&& rm -rf ~/.cache
|
|
|
|
CMD ["python", "-m", "monitoringdaemon"]
|
|
|
|
Third, we need to define the container in the docker-compose configuration.
|
|
|
|
Put next lines into the ``docker-compose.yml`` file:
|
|
|
|
.. code-block:: yaml
|
|
|
|
version: "3.7"
|
|
|
|
services:
|
|
|
|
monitor:
|
|
build: ./
|
|
image: monitoring-daemon
|
|
volumes:
|
|
- "./:/code"
|
|
|
|
All is ready. Let's check that the environment is setup properly.
|
|
|
|
Run in the terminal:
|
|
|
|
.. code-block:: bash
|
|
|
|
docker-compose build
|
|
|
|
The build process may take a couple of minutes. You should see something like this in the end:
|
|
|
|
.. code-block:: bash
|
|
|
|
Successfully built 5b4ee5e76e35
|
|
Successfully tagged monitoring-daemon:latest
|
|
|
|
After the build is done run the container:
|
|
|
|
.. code-block:: bash
|
|
|
|
docker-compose up
|
|
|
|
The output should look like:
|
|
|
|
.. code-block:: bash
|
|
|
|
Creating network "asyncio-daemon-tutorial_default" with the default driver
|
|
Creating asyncio-daemon-tutorial_monitor_1 ... done
|
|
Attaching to asyncio-daemon-tutorial_monitor_1
|
|
asyncio-daemon-tutorial_monitor_1 exited with code 0
|
|
|
|
The environment is ready. The application does not do any work and just exits with a code ``0``.
|
|
|
|
Next step is to configure the logging and configuration file parsing.
|
|
|
|
Logging and configuration
|
|
-------------------------
|
|
|
|
In this section we will configure the logging and configuration file parsing.
|
|
|
|
Let's start with the the main part of our application - the container. Container will keep all of
|
|
the application components and their dependencies.
|
|
|
|
First two components that we're going to add are the config object and the provider for
|
|
configuring the logging.
|
|
|
|
Put next lines into the ``containers.py`` file:
|
|
|
|
.. code-block:: python
|
|
|
|
"""Containers module."""
|
|
|
|
import logging
|
|
import sys
|
|
|
|
from dependency_injector import containers, providers
|
|
|
|
|
|
class Container(containers.DeclarativeContainer):
|
|
|
|
config = providers.Configuration()
|
|
|
|
logging = providers.Resource(
|
|
logging.basicConfig,
|
|
stream=sys.stdout,
|
|
level=config.log.level,
|
|
format=config.log.format,
|
|
)
|
|
|
|
.. note::
|
|
|
|
We have used the configuration value before it was defined. That's the principle how the
|
|
``Configuration`` provider works.
|
|
|
|
Use first, define later.
|
|
|
|
The configuration file will keep the logging settings.
|
|
|
|
Put next lines into the ``config.yml`` file:
|
|
|
|
.. code-block:: yaml
|
|
|
|
log:
|
|
level: "INFO"
|
|
format: "[%(asctime)s] [%(levelname)s] [%(name)s]: %(message)s"
|
|
|
|
Now let's create the function that will run our daemon. It's traditionally called
|
|
``main()``. The ``main()`` function will create the container. Then it will use the container
|
|
to parse the ``config.yml`` file and call the logging configuration provider.
|
|
|
|
Put next lines into the ``__main__.py`` file:
|
|
|
|
.. code-block:: python
|
|
|
|
"""Main module."""
|
|
|
|
from .containers import Container
|
|
|
|
|
|
def main() -> None:
|
|
...
|
|
|
|
|
|
if __name__ == '__main__':
|
|
container = Container()
|
|
container.config.from_yaml('config.yml')
|
|
container.init_resources()
|
|
|
|
main()
|
|
|
|
.. note::
|
|
|
|
Container is the first object in the application.
|
|
|
|
Logging and configuration parsing part is done. In next section we will create the monitoring
|
|
checks dispatcher.
|
|
|
|
Dispatcher
|
|
----------
|
|
|
|
Now let's add the monitoring checks dispatcher.
|
|
|
|
The dispatcher will control a list of the monitoring tasks. It will execute each task according
|
|
to the configured schedule. The ``Monitor`` class is the base class for all the monitors. You can
|
|
create different monitors by subclassing it and implementing the ``check()`` method.
|
|
|
|
.. image:: asyncio-images/classes-01.png
|
|
|
|
Let's create dispatcher and the monitor base classes.
|
|
|
|
Create ``dispatcher.py`` and ``monitors.py`` in the ``monitoringdaemon`` package:
|
|
|
|
.. code-block:: bash
|
|
:emphasize-lines: 6-7
|
|
|
|
./
|
|
├── monitoringdaemon/
|
|
│ ├── __init__.py
|
|
│ ├── __main__.py
|
|
│ ├── containers.py
|
|
│ ├── dispatcher.py
|
|
│ └── monitors.py
|
|
├── config.yml
|
|
├── docker-compose.yml
|
|
├── Dockerfile
|
|
└── requirements.txt
|
|
|
|
Put next into the ``monitors.py``:
|
|
|
|
.. code-block:: python
|
|
|
|
"""Monitors module."""
|
|
|
|
import logging
|
|
|
|
|
|
class Monitor:
|
|
|
|
def __init__(self, check_every: int) -> None:
|
|
self.check_every = check_every
|
|
self.logger = logging.getLogger(self.__class__.__name__)
|
|
|
|
async def check(self) -> None:
|
|
raise NotImplementedError()
|
|
|
|
and next into the ``dispatcher.py``:
|
|
|
|
.. code-block:: python
|
|
|
|
"""Dispatcher module."""
|
|
|
|
import asyncio
|
|
import logging
|
|
import signal
|
|
import time
|
|
from typing import List
|
|
|
|
from .monitors import Monitor
|
|
|
|
|
|
class Dispatcher:
|
|
|
|
def __init__(self, monitors: List[Monitor]) -> None:
|
|
self._monitors = monitors
|
|
self._monitor_tasks: List[asyncio.Task] = []
|
|
self._logger = logging.getLogger(self.__class__.__name__)
|
|
self._stopping = False
|
|
|
|
def run(self) -> None:
|
|
asyncio.run(self.start())
|
|
|
|
async def start(self) -> None:
|
|
self._logger.info('Starting up')
|
|
|
|
for monitor in self._monitors:
|
|
self._monitor_tasks.append(
|
|
asyncio.create_task(self._run_monitor(monitor)),
|
|
)
|
|
|
|
asyncio.get_event_loop().add_signal_handler(signal.SIGTERM, self.stop)
|
|
asyncio.get_event_loop().add_signal_handler(signal.SIGINT, self.stop)
|
|
|
|
await asyncio.gather(*self._monitor_tasks, return_exceptions=True)
|
|
|
|
self.stop()
|
|
|
|
def stop(self) -> None:
|
|
if self._stopping:
|
|
return
|
|
|
|
self._stopping = True
|
|
|
|
self._logger.info('Shutting down')
|
|
for task, monitor in zip(self._monitor_tasks, self._monitors):
|
|
task.cancel()
|
|
self._monitor_tasks.clear()
|
|
self._logger.info('Shutdown finished successfully')
|
|
|
|
@staticmethod
|
|
async def _run_monitor(monitor: Monitor) -> None:
|
|
def _until_next(last: float) -> float:
|
|
time_took = time.time() - last
|
|
return monitor.check_every - time_took
|
|
|
|
while True:
|
|
time_start = time.time()
|
|
|
|
try:
|
|
await monitor.check()
|
|
except asyncio.CancelledError:
|
|
break
|
|
except Exception:
|
|
monitor.logger.exception('Error executing monitor check')
|
|
|
|
await asyncio.sleep(_until_next(last=time_start))
|
|
|
|
Now we need to add the dispatcher to the container.
|
|
|
|
Edit ``containers.py``:
|
|
|
|
.. code-block:: python
|
|
:emphasize-lines: 8,22-27
|
|
|
|
"""Containers module."""
|
|
|
|
import logging
|
|
import sys
|
|
|
|
from dependency_injector import containers, providers
|
|
|
|
from . import dispatcher
|
|
|
|
|
|
class Container(containers.DeclarativeContainer):
|
|
|
|
config = providers.Configuration()
|
|
|
|
logging = providers.Resource(
|
|
logging.basicConfig,
|
|
stream=sys.stdout,
|
|
level=config.log.level,
|
|
format=config.log.format,
|
|
)
|
|
|
|
dispatcher = providers.Factory(
|
|
dispatcher.Dispatcher,
|
|
monitors=providers.List(
|
|
# TODO: add monitors
|
|
),
|
|
)
|
|
|
|
At the last we will inject dispatcher into the ``main()`` function
|
|
and call the ``run()`` method. We will use :ref:`wiring` feature.
|
|
|
|
|
|
Edit ``__main__.py``:
|
|
|
|
.. code-block:: python
|
|
:emphasize-lines: 3-7,11-13,20
|
|
|
|
"""Main module."""
|
|
|
|
import sys
|
|
|
|
from dependency_injector.wiring import inject, Provide
|
|
|
|
from .dispatcher import Dispatcher
|
|
from .containers import Container
|
|
|
|
|
|
@inject
|
|
def main(dispatcher: Dispatcher = Provide[Container.dispatcher]) -> None:
|
|
dispatcher.run()
|
|
|
|
|
|
if __name__ == '__main__':
|
|
container = Container()
|
|
container.config.from_yaml('config.yml')
|
|
container.init_resources()
|
|
container.wire(modules=[sys.modules[__name__]])
|
|
|
|
main()
|
|
|
|
Finally let's start the daemon to check that all works.
|
|
|
|
Run in the terminal:
|
|
|
|
.. code-block:: bash
|
|
|
|
docker-compose up
|
|
|
|
The output should look like:
|
|
|
|
.. code-block:: bash
|
|
|
|
Starting asyncio-daemon-tutorial_monitor_1 ... done
|
|
Attaching to asyncio-daemon-tutorial_monitor_1
|
|
monitor_1 | [2020-08-08 16:12:35,772] [INFO] [Dispatcher]: Starting up
|
|
monitor_1 | [2020-08-08 16:12:35,774] [INFO] [Dispatcher]: Shutting down
|
|
monitor_1 | [2020-08-08 16:12:35,774] [INFO] [Dispatcher]: Shutdown finished successfully
|
|
asyncio-daemon-tutorial_monitor_1 exited with code 0
|
|
|
|
Everything works properly. Dispatcher starts up and exits because there are no monitoring tasks.
|
|
|
|
By the end of this section we have the application skeleton ready. In next section will will
|
|
add first monitoring task.
|
|
|
|
Example.com monitor
|
|
-------------------
|
|
|
|
In this section we will add a monitoring task that will check the availability of the
|
|
`http://example.com <http://example.com>`_.
|
|
|
|
We will start from the extending of our class model with a new type of the monitoring check, the
|
|
``HttpMonitor``.
|
|
|
|
The ``HttpMonitor`` is a subclass of the ``Monitor``. We will implement the ``check()`` method that
|
|
will send the HTTP request to the specified URL. The http request sending will be delegated to
|
|
the ``HttpClient``.
|
|
|
|
.. image:: asyncio-images/classes-02.png
|
|
|
|
First we need to create the ``HttpClient``.
|
|
|
|
Create ``http.py`` in the ``monitoringdaemon`` package:
|
|
|
|
.. code-block:: bash
|
|
:emphasize-lines: 7
|
|
|
|
./
|
|
├── monitoringdaemon/
|
|
│ ├── __init__.py
|
|
│ ├── __main__.py
|
|
│ ├── containers.py
|
|
│ ├── dispatcher.py
|
|
│ ├── http.py
|
|
│ └── monitors.py
|
|
├── config.yml
|
|
├── docker-compose.yml
|
|
├── Dockerfile
|
|
└── requirements.txt
|
|
|
|
and put next into it:
|
|
|
|
.. code-block:: python
|
|
|
|
"""Http client module."""
|
|
|
|
from aiohttp import ClientSession, ClientTimeout, ClientResponse
|
|
|
|
|
|
class HttpClient:
|
|
|
|
async def request(self, method: str, url: str, timeout: int) -> ClientResponse:
|
|
async with ClientSession(timeout=ClientTimeout(timeout)) as session:
|
|
async with session.request(method, url) as response:
|
|
return response
|
|
|
|
Now we need to add the ``HttpClient`` to the container.
|
|
|
|
Edit ``containers.py``:
|
|
|
|
.. code-block:: python
|
|
:emphasize-lines: 8,22
|
|
|
|
"""Containers module."""
|
|
|
|
import logging
|
|
import sys
|
|
|
|
from dependency_injector import containers, providers
|
|
|
|
from . import http, dispatcher
|
|
|
|
|
|
class Container(containers.DeclarativeContainer):
|
|
|
|
config = providers.Configuration()
|
|
|
|
logging = providers.Resource(
|
|
logging.basicConfig,
|
|
stream=sys.stdout,
|
|
level=config.log.level,
|
|
format=config.log.format,
|
|
)
|
|
|
|
http_client = providers.Factory(http.HttpClient)
|
|
|
|
dispatcher = providers.Factory(
|
|
dispatcher.Dispatcher,
|
|
monitors=providers.List(
|
|
# TODO: add monitors
|
|
),
|
|
)
|
|
|
|
Now we're ready to add the ``HttpMonitor``. We will add it to the ``monitors`` module.
|
|
|
|
Edit ``monitors.py``:
|
|
|
|
.. code-block:: python
|
|
:emphasize-lines: 4-7,20-56
|
|
|
|
"""Monitors module."""
|
|
|
|
import logging
|
|
import time
|
|
from typing import Dict, Any
|
|
|
|
from .http import HttpClient
|
|
|
|
|
|
class Monitor:
|
|
|
|
def __init__(self, check_every: int) -> None:
|
|
self.check_every = check_every
|
|
self.logger = logging.getLogger(self.__class__.__name__)
|
|
|
|
async def check(self) -> None:
|
|
raise NotImplementedError()
|
|
|
|
|
|
class HttpMonitor(Monitor):
|
|
|
|
def __init__(
|
|
self,
|
|
http_client: HttpClient,
|
|
options: Dict[str, Any],
|
|
) -> None:
|
|
self._client = http_client
|
|
self._method = options.pop('method')
|
|
self._url = options.pop('url')
|
|
self._timeout = options.pop('timeout')
|
|
super().__init__(check_every=options.pop('check_every'))
|
|
|
|
async def check(self) -> None:
|
|
time_start = time.time()
|
|
|
|
response = await self._client.request(
|
|
method=self._method,
|
|
url=self._url,
|
|
timeout=self._timeout,
|
|
)
|
|
|
|
time_end = time.time()
|
|
time_took = time_end - time_start
|
|
|
|
self.logger.info(
|
|
'Check\n'
|
|
' %s %s\n'
|
|
' response code: %s\n'
|
|
' content length: %s\n'
|
|
' request took: %s seconds',
|
|
self._method,
|
|
self._url,
|
|
response.status,
|
|
response.content_length,
|
|
round(time_took, 3)
|
|
)
|
|
|
|
We have everything ready to add the `http://example.com <http://example.com>`_ monitoring check.
|
|
We make two changes in the container:
|
|
|
|
- Add the factory provider ``example_monitor``.
|
|
- Inject the ``example_monitor`` into the dispatcher.
|
|
|
|
Edit ``containers.py``:
|
|
|
|
.. code-block:: python
|
|
:emphasize-lines: 8,24-28,33
|
|
|
|
"""Containers module."""
|
|
|
|
import logging
|
|
import sys
|
|
|
|
from dependency_injector import containers, providers
|
|
|
|
from . import http, monitors, dispatcher
|
|
|
|
|
|
class Container(containers.DeclarativeContainer):
|
|
|
|
config = providers.Configuration()
|
|
|
|
logging = providers.Resource(
|
|
logging.basicConfig,
|
|
stream=sys.stdout,
|
|
level=config.log.level,
|
|
format=config.log.format,
|
|
)
|
|
|
|
http_client = providers.Factory(http.HttpClient)
|
|
|
|
example_monitor = providers.Factory(
|
|
monitors.HttpMonitor,
|
|
http_client=http_client,
|
|
options=config.monitors.example,
|
|
)
|
|
|
|
dispatcher = providers.Factory(
|
|
dispatcher.Dispatcher,
|
|
monitors=providers.List(
|
|
example_monitor,
|
|
),
|
|
)
|
|
|
|
Provider ``example_monitor`` has a dependency on the configuration options. Let's define these
|
|
options.
|
|
|
|
Edit ``config.yml``:
|
|
|
|
.. code-block:: yaml
|
|
:emphasize-lines: 5-11
|
|
|
|
log:
|
|
level: "INFO"
|
|
format: "[%(asctime)s] [%(levelname)s] [%(name)s]: %(message)s"
|
|
|
|
monitors:
|
|
|
|
example:
|
|
method: "GET"
|
|
url: "http://example.com"
|
|
timeout: 5
|
|
check_every: 5
|
|
|
|
|
|
All set. Start the daemon to check that all works.
|
|
|
|
Run in the terminal:
|
|
|
|
.. code-block:: bash
|
|
|
|
docker-compose up
|
|
|
|
You should see:
|
|
|
|
.. code-block:: bash
|
|
|
|
Starting asyncio-daemon-tutorial_monitor_1 ... done
|
|
Attaching to asyncio-daemon-tutorial_monitor_1
|
|
monitor_1 | [2020-08-08 17:06:41,965] [INFO] [Dispatcher]: Starting up
|
|
monitor_1 | [2020-08-08 17:06:42,033] [INFO] [HttpMonitor]: Check
|
|
monitor_1 | GET http://example.com
|
|
monitor_1 | response code: 200
|
|
monitor_1 | content length: 648
|
|
monitor_1 | request took: 0.067 seconds
|
|
monitor_1 | [2020-08-08 17:06:47,040] [INFO] [HttpMonitor]: Check
|
|
monitor_1 | GET http://example.com
|
|
monitor_1 | response code: 200
|
|
monitor_1 | content length: 648
|
|
monitor_1 | request took: 0.073 seconds
|
|
|
|
Our daemon can monitor `http://example.com <http://example.com>`_ availability.
|
|
|
|
Let's add a monitor for the `https://httpbin.org <https://httpbin.org>`_.
|
|
|
|
Httpbin.org monitor
|
|
-------------------
|
|
|
|
Adding of a monitor for the `https://httpbin.org <https://httpbin.org>`_ will be much
|
|
easier because we have all the components ready. We just need to create a new provider
|
|
in the container and update the configuration.
|
|
|
|
Edit ``containers.py``:
|
|
|
|
.. code-block:: python
|
|
:emphasize-lines: 30-34,40
|
|
|
|
"""Containers module."""
|
|
|
|
import logging
|
|
import sys
|
|
|
|
from dependency_injector import containers, providers
|
|
|
|
from . import http, monitors, dispatcher
|
|
|
|
|
|
class Container(containers.DeclarativeContainer):
|
|
|
|
config = providers.Configuration()
|
|
|
|
logging = providers.Resource(
|
|
logging.basicConfig,
|
|
stream=sys.stdout,
|
|
level=config.log.level,
|
|
format=config.log.format,
|
|
)
|
|
|
|
http_client = providers.Factory(http.HttpClient)
|
|
|
|
example_monitor = providers.Factory(
|
|
monitors.HttpMonitor,
|
|
http_client=http_client,
|
|
options=config.monitors.example,
|
|
)
|
|
|
|
httpbin_monitor = providers.Factory(
|
|
monitors.HttpMonitor,
|
|
http_client=http_client,
|
|
options=config.monitors.httpbin,
|
|
)
|
|
|
|
dispatcher = providers.Factory(
|
|
dispatcher.Dispatcher,
|
|
monitors=providers.List(
|
|
example_monitor,
|
|
httpbin_monitor,
|
|
),
|
|
)
|
|
|
|
Edit ``config.yml``:
|
|
|
|
.. code-block:: yaml
|
|
:emphasize-lines: 13-17
|
|
|
|
log:
|
|
level: "INFO"
|
|
format: "[%(asctime)s] [%(levelname)s] [%(name)s]: %(message)s"
|
|
|
|
monitors:
|
|
|
|
example:
|
|
method: "GET"
|
|
url: "http://example.com"
|
|
timeout: 5
|
|
check_every: 5
|
|
|
|
httpbin:
|
|
method: "GET"
|
|
url: "https://httpbin.org/get"
|
|
timeout: 5
|
|
check_every: 5
|
|
|
|
Let's start the daemon and check the logs.
|
|
|
|
Run in the terminal:
|
|
|
|
.. code-block:: bash
|
|
|
|
docker-compose up
|
|
|
|
You should see:
|
|
|
|
.. code-block:: bash
|
|
|
|
Starting asyncio-daemon-tutorial_monitor_1 ... done
|
|
Attaching to asyncio-daemon-tutorial_monitor_1
|
|
monitor_1 | [2020-08-08 18:09:08,540] [INFO] [Dispatcher]: Starting up
|
|
monitor_1 | [2020-08-08 18:09:08,618] [INFO] [HttpMonitor]: Check
|
|
monitor_1 | GET http://example.com
|
|
monitor_1 | response code: 200
|
|
monitor_1 | content length: 648
|
|
monitor_1 | request took: 0.077 seconds
|
|
monitor_1 | [2020-08-08 18:09:08,722] [INFO] [HttpMonitor]: Check
|
|
monitor_1 | GET https://httpbin.org/get
|
|
monitor_1 | response code: 200
|
|
monitor_1 | content length: 310
|
|
monitor_1 | request took: 0.18 seconds
|
|
monitor_1 | [2020-08-08 18:09:13,619] [INFO] [HttpMonitor]: Check
|
|
monitor_1 | GET http://example.com
|
|
monitor_1 | response code: 200
|
|
monitor_1 | content length: 648
|
|
monitor_1 | request took: 0.066 seconds
|
|
monitor_1 | [2020-08-08 18:09:13,681] [INFO] [HttpMonitor]: Check
|
|
monitor_1 | GET https://httpbin.org/get
|
|
monitor_1 | response code: 200
|
|
monitor_1 | content length: 310
|
|
monitor_1 | request took: 0.126 seconds
|
|
|
|
The functional part is done. Daemon monitors `http://example.com <http://example.com>`_ and
|
|
`https://httpbin.org <https://httpbin.org>`_.
|
|
|
|
In next section we will add some tests.
|
|
|
|
Tests
|
|
-----
|
|
|
|
In this section we will add some tests.
|
|
|
|
We will use `pytest <https://docs.pytest.org/en/stable/>`_ and
|
|
`coverage <https://coverage.readthedocs.io/>`_.
|
|
|
|
Create ``tests.py`` in the ``monitoringdaemon`` package:
|
|
|
|
.. code-block:: bash
|
|
:emphasize-lines: 9
|
|
|
|
./
|
|
├── monitoringdaemon/
|
|
│ ├── __init__.py
|
|
│ ├── __main__.py
|
|
│ ├── containers.py
|
|
│ ├── dispatcher.py
|
|
│ ├── http.py
|
|
│ ├── monitors.py
|
|
│ └── tests.py
|
|
├── config.yml
|
|
├── docker-compose.yml
|
|
├── Dockerfile
|
|
└── requirements.txt
|
|
|
|
and put next into it:
|
|
|
|
.. code-block:: python
|
|
:emphasize-lines: 54,70-71
|
|
|
|
"""Tests module."""
|
|
|
|
import asyncio
|
|
import dataclasses
|
|
from unittest import mock
|
|
|
|
import pytest
|
|
|
|
from .containers import Container
|
|
|
|
|
|
@dataclasses.dataclass
|
|
class RequestStub:
|
|
status: int
|
|
content_length: int
|
|
|
|
|
|
@pytest.fixture
|
|
def container():
|
|
container = Container()
|
|
container.config.from_dict({
|
|
'log': {
|
|
'level': 'INFO',
|
|
'formant': '[%(asctime)s] [%(levelname)s] [%(name)s]: %(message)s',
|
|
},
|
|
'monitors': {
|
|
'example': {
|
|
'method': 'GET',
|
|
'url': 'http://fake-example.com',
|
|
'timeout': 1,
|
|
'check_every': 1,
|
|
},
|
|
'httpbin': {
|
|
'method': 'GET',
|
|
'url': 'https://fake-httpbin.org/get',
|
|
'timeout': 1,
|
|
'check_every': 1,
|
|
},
|
|
},
|
|
})
|
|
return container
|
|
|
|
|
|
@pytest.mark.asyncio
|
|
async def test_example_monitor(container, caplog):
|
|
caplog.set_level('INFO')
|
|
|
|
http_client_mock = mock.AsyncMock()
|
|
http_client_mock.request.return_value = RequestStub(
|
|
status=200,
|
|
content_length=635,
|
|
)
|
|
|
|
with container.http_client.override(http_client_mock):
|
|
example_monitor = container.example_monitor()
|
|
await example_monitor.check()
|
|
|
|
assert 'http://fake-example.com' in caplog.text
|
|
assert 'response code: 200' in caplog.text
|
|
assert 'content length: 635' in caplog.text
|
|
|
|
|
|
@pytest.mark.asyncio
|
|
async def test_dispatcher(container, caplog, event_loop):
|
|
caplog.set_level('INFO')
|
|
|
|
example_monitor_mock = mock.AsyncMock()
|
|
httpbin_monitor_mock = mock.AsyncMock()
|
|
|
|
with container.example_monitor.override(example_monitor_mock), \
|
|
container.httpbin_monitor.override(httpbin_monitor_mock):
|
|
|
|
dispatcher = container.dispatcher()
|
|
event_loop.create_task(dispatcher.start())
|
|
await asyncio.sleep(0.1)
|
|
dispatcher.stop()
|
|
|
|
assert example_monitor_mock.check.called
|
|
assert httpbin_monitor_mock.check.called
|
|
|
|
Run in the terminal:
|
|
|
|
.. code-block:: bash
|
|
|
|
docker-compose run --rm monitor py.test monitoringdaemon/tests.py --cov=monitoringdaemon
|
|
|
|
You should see:
|
|
|
|
.. code-block:: bash
|
|
|
|
platform linux -- Python 3.8.3, pytest-6.0.1, py-1.9.0, pluggy-0.13.1
|
|
rootdir: /code
|
|
plugins: asyncio-0.14.0, cov-2.10.0
|
|
collected 2 items
|
|
|
|
monitoringdaemon/tests.py .. [100%]
|
|
|
|
----------- coverage: platform linux, python 3.8.3-final-0 -----------
|
|
Name Stmts Miss Cover
|
|
----------------------------------------------------
|
|
monitoringdaemon/__init__.py 0 0 100%
|
|
monitoringdaemon/__main__.py 13 13 0%
|
|
monitoringdaemon/containers.py 11 0 100%
|
|
monitoringdaemon/dispatcher.py 44 5 89%
|
|
monitoringdaemon/http.py 6 3 50%
|
|
monitoringdaemon/monitors.py 23 1 96%
|
|
monitoringdaemon/tests.py 37 0 100%
|
|
----------------------------------------------------
|
|
TOTAL 134 22 84%
|
|
|
|
.. note::
|
|
|
|
Take a look at the highlights in the ``tests.py``.
|
|
|
|
In the ``test_example_monitor`` it emphasizes the overriding of the ``HttpClient``. The real
|
|
HTTP calls are mocked.
|
|
|
|
In the ``test_dispatcher`` we override both monitors with the mocks.
|
|
|
|
|
|
Conclusion
|
|
----------
|
|
|
|
In this tutorial we've built an ``asyncio`` monitoring daemon following the dependency
|
|
injection principle.
|
|
We've used the ``Dependency Injector`` as a dependency injection framework.
|
|
|
|
With a help of :ref:`containers` and :ref:`providers` we have defined how to assemble application components.
|
|
|
|
``List`` provider helped to inject a list of monitors into dispatcher.
|
|
:ref:`configuration-provider` helped to deal with reading YAML file.
|
|
|
|
We used :ref:`wiring` feature to inject dispatcher into the ``main()`` function.
|
|
:ref:`provider-overriding` feature helped in testing.
|
|
|
|
We kept all the dependencies injected explicitly. This will help when you need to add or
|
|
change something in future.
|
|
|
|
You can find complete project on the
|
|
`Github <https://github.com/ets-labs/python-dependency-injector/tree/master/examples/miniapps/asyncio-daemon>`_.
|
|
|
|
What's next?
|
|
|
|
- Look at the other :ref:`tutorials`
|
|
- Know more about the :ref:`providers`
|
|
- Go to the :ref:`contents`
|
|
|
|
.. disqus::
|