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Unified interface to retrieve the Redis bus configuration.

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A common `utils.get_redis_conf` has been created to handle the cascade
fallback logic used to retrive the default Redis configuration.
This commit is contained in:
Fabio Manganiello 2023-07-24 01:04:13 +02:00
parent 77ffefdccb
commit e9a568fdd2
Signed by: blacklight
GPG key ID: D90FBA7F76362774
5 changed files with 170 additions and 32 deletions
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111
platypush/app.py
View file

@ -1,6 +1,7 @@
import argparse
import logging
import os
import subprocess
import sys
from typing import Optional
@ -16,7 +17,7 @@ from .message.event import Event
from .message.event.application import ApplicationStartedEvent
from .message.request import Request
from .message.response import Response
from .utils import get_enabled_plugins
from .utils import get_enabled_plugins, get_redis_conf
log = logging.getLogger('platypush')
@ -27,6 +28,9 @@ class Application:
# Default bus queue name
_default_redis_queue = 'platypush/bus'
# Default Redis port
_default_redis_port = 6379
# backend_name => backend_obj map
backends = None
@ -42,6 +46,9 @@ class Application:
no_capture_stderr: bool = False,
redis_queue: Optional[str] = None,
verbose: bool = False,
start_redis: bool = False,
redis_host: Optional[str] = None,
redis_port: Optional[int] = None,
):
"""
:param config_file: Configuration file override (default: None).
@ -58,6 +65,15 @@ class Application:
messages (default: platypush/bus).
:param verbose: Enable debug/verbose logging, overriding the stored
configuration (default: False).
:param start_redis: If set, it starts a managed Redis instance upon
boot (it requires the ``redis-server`` executable installed on the
server). This is particularly useful when running the application
inside of Docker containers, without relying on ``docker-compose``
to start multiple containers, and in tests (default: False).
:param redis_host: Host of the Redis server to be used. It overrides
the settings in the ``redis`` section of the configuration file.
:param redis_port: Port of the local Redis server. It overrides the
settings in the ``redis`` section of the configuration file.
"""
self.pidfile = pidfile
@ -78,16 +94,29 @@ class Application:
self.requests_to_process = requests_to_process
self.processed_requests = 0
self.cron_scheduler = None
self.start_redis = start_redis
self.redis_host = redis_host
self.redis_port = redis_port
self.redis_conf = {}
self._redis_proc: Optional[subprocess.Popen] = None
self._init_bus()
self._init_logging()
def _init_bus(self):
redis_conf = Config.get('backend.redis') or {}
self._redis_conf = get_redis_conf()
self._redis_conf['port'] = self.redis_port or self._redis_conf.get(
'port', self._default_redis_port
)
if self.redis_host:
self._redis_conf['host'] = self.redis_host
Config.set('redis', self._redis_conf)
self.bus = RedisBus(
redis_queue=self.redis_queue,
on_message=self.on_message(),
**redis_conf.get('redis_args', {})
**self._redis_conf,
)
def _init_logging(self):
@ -96,6 +125,37 @@ class Application:
logging_conf['level'] = logging.DEBUG
logging.basicConfig(**logging_conf)
def _start_redis(self):
if self._redis_proc and self._redis_proc.poll() is None:
log.warning(
'A local Redis instance is already running, refusing to start it again'
)
return
port = self._redis_conf['port']
log.info('Starting local Redis instance on %s', port)
self._redis_proc = subprocess.Popen(
[
'redis-server',
'--bind',
'localhost',
'--port',
str(port),
],
stdout=subprocess.PIPE,
)
log.info('Waiting for Redis to start')
for line in self._redis_proc.stdout: # type: ignore
if b'Ready to accept connections' in line:
break
def _stop_redis(self):
if self._redis_proc and self._redis_proc.poll() is None:
log.info('Stopping local Redis instance')
self._redis_proc.kill()
self._redis_proc = None
@classmethod
def build(cls, *args: str):
"""
@ -104,6 +164,7 @@ class Application:
from . import __version__
parser = argparse.ArgumentParser()
parser.add_argument(
'--config',
'-c',
@ -112,6 +173,7 @@ class Application:
default=None,
help='Custom location for the configuration file',
)
parser.add_argument(
'--version',
dest='version',
@ -119,6 +181,7 @@ class Application:
action='store_true',
help="Print the current version and exit",
)
parser.add_argument(
'--verbose',
'-v',
@ -127,6 +190,7 @@ class Application:
action='store_true',
help="Enable verbose/debug logging",
)
parser.add_argument(
'--pidfile',
'-P',
@ -137,6 +201,7 @@ class Application:
+ "store its PID, useful if you're planning to "
+ "integrate it in a service",
)
parser.add_argument(
'--no-capture-stdout',
dest='no_capture_stdout',
@ -146,6 +211,7 @@ class Application:
+ "exceeded errors so stdout won't be captured by "
+ "the logging system",
)
parser.add_argument(
'--no-capture-stderr',
dest='no_capture_stderr',
@ -155,6 +221,7 @@ class Application:
+ "exceeded errors so stderr won't be captured by "
+ "the logging system",
)
parser.add_argument(
'--redis-queue',
dest='redis_queue',
@ -164,6 +231,34 @@ class Application:
"(default: platypush/bus)",
)
parser.add_argument(
'--start-redis',
dest='start_redis',
required=False,
action='store_true',
help="Set this flag if you want to run and manage Redis internally "
"from the app rather than using an external server. It requires the "
"redis-server executable to be present in the path",
)
parser.add_argument(
'--redis-host',
dest='redis_host',
required=False,
default=None,
help="Overrides the host specified in the redis section of the "
"configuration file",
)
parser.add_argument(
'--redis-port',
dest='redis_port',
required=False,
default=None,
help="Overrides the port specified in the redis section of the "
"configuration file",
)
opts, _ = parser.parse_known_args(args)
if opts.version:
print(__version__)
@ -176,6 +271,9 @@ class Application:
no_capture_stderr=opts.no_capture_stderr,
redis_queue=opts.redis_queue,
verbose=opts.verbose,
start_redis=opts.start_redis,
redis_host=opts.redis_host,
redis_port=opts.redis_port,
)
def on_message(self):
@ -234,6 +332,9 @@ class Application:
self.entities_engine.stop()
self.entities_engine = None
if self.start_redis:
self._stop_redis()
def run(self):
"""Start the daemon."""
from . import __version__
@ -245,6 +346,10 @@ class Application:
log.info('---- Starting platypush v.%s', __version__)
# Start the local Redis service if required
if self.start_redis:
self._start_redis()
# Initialize the backends and link them to the bus
self.backends = register_backends(bus=self.bus, global_scope=True)

38
platypush/backend/http/app/utils/bus.py
View file

@ -5,7 +5,7 @@ from platypush.config import Config
from platypush.context import get_backend
from platypush.message import Message
from platypush.message.request import Request
from platypush.utils import get_redis_queue_name_by_message
from platypush.utils import get_redis_conf, get_redis_queue_name_by_message
from .logger import logger
@ -13,17 +13,27 @@ _bus = None
def bus():
global _bus
"""
Lazy getter/initializer for the bus object.
"""
global _bus # pylint: disable=global-statement
if _bus is None:
redis_queue = get_backend('http').bus.redis_queue # type: ignore
_bus = RedisBus(redis_queue=redis_queue)
_bus = RedisBus(**get_redis_conf(), redis_queue=redis_queue)
return _bus
def send_message(msg, wait_for_response=True):
"""
Send a message to the bus.
:param msg: The message to send.
:param wait_for_response: If ``True``, wait for the response to be received
before returning, otherwise return immediately.
"""
msg = Message.build(msg)
if msg is None:
return
return None
if isinstance(msg, Request):
msg.origin = 'http'
@ -35,12 +45,22 @@ def send_message(msg, wait_for_response=True):
if isinstance(msg, Request) and wait_for_response:
response = get_message_response(msg)
logger().debug('Processing response on the HTTP backend: {}'.format(response))
logger().debug('Processing response on the HTTP backend: %s', response)
return response
return None
def send_request(action, wait_for_response=True, **kwargs):
"""
Send a request to the bus.
:param action: The action to send.
:param wait_for_response: If ``True``, wait for the response to be received
before returning, otherwise return immediately.
:param kwargs: Additional arguments to pass to the action.
"""
msg = {'type': 'request', 'action': action}
if kwargs:
@ -50,10 +70,16 @@ def send_request(action, wait_for_response=True, **kwargs):
def get_message_response(msg):
"""
Get the response to the given message.
:param msg: The message to get the response for.
:return: The response to the given message.
"""
redis = Redis(**bus().redis_args)
redis_queue = get_redis_queue_name_by_message(msg)
if not redis_queue:
return
return None
response = redis.blpop(redis_queue, timeout=60)
if response and len(response) > 1:

10
platypush/bus/redis.py
View file

@ -29,7 +29,6 @@ class RedisBus(Bus):
"""
Reads one message from the Redis queue
"""
try:
if self.should_stop():
return None
@ -49,8 +48,17 @@ class RedisBus(Bus):
"""
Sends a message to the Redis queue
"""
from redis import exceptions
try:
return self.redis.rpush(self.redis_queue, str(msg))
except exceptions.ConnectionError as e:
if not self.should_stop():
# Raise the exception only if the bus it not supposed to be
# stopped
raise e
return None
def stop(self):
super().stop()

16
platypush/plugins/redis/__init__.py
View file

@ -1,7 +1,7 @@
from redis import Redis
from platypush.context import get_backend
from platypush.plugins import Plugin, action
from platypush.utils import get_redis_conf
class RedisPlugin(Plugin):
@ -12,15 +12,7 @@ class RedisPlugin(Plugin):
def __init__(self, *args, **kwargs):
super().__init__()
self.args = args
self.kwargs = kwargs
if not kwargs:
try:
redis_backend = get_backend('redis')
if redis_backend and redis_backend.redis_args:
self.kwargs = redis_backend.redis_args
except Exception as e:
self.logger.debug(e)
self.kwargs = kwargs or get_redis_conf()
def _get_redis(self):
return Redis(*self.args, **self.kwargs)
@ -58,7 +50,7 @@ class RedisPlugin(Plugin):
"""
return {
keys[i]: value.decode() if value else value
keys[i]: value.decode() if isinstance(value, bytes) else value
for (i, value) in enumerate(self._get_redis().mget(keys, *args))
}
@ -75,7 +67,7 @@ class RedisPlugin(Plugin):
# broke back-compatibility with the previous way of passing
# key-value pairs to mset directly on kwargs. This try-catch block
# is to support things on all the redis-py versions
return self._get_redis().mset(mapping=kwargs)
return self._get_redis().mset(mapping=kwargs) # type: ignore
@action
def expire(self, key, expiration):

25
platypush/utils/__init__.py
View file

@ -559,24 +559,31 @@ def get_enabled_plugins() -> dict:
return plugins
def get_redis_conf() -> dict:
"""
Get the Redis connection arguments from the configuration.
"""
from platypush.config import Config
return (
Config.get('redis')
or (Config.get('backend.redis') or {}).get('redis_args', {})
or {}
)
def get_redis(*args, **kwargs) -> Redis:
"""
Get a Redis client on the basis of the Redis configuration.
The Redis configuration can be loaded from:
1. The ``backend.redis`` configuration (``redis_args`` attribute)
2. The ``redis`` plugin.
1. The ``redis`` plugin.
2. The ``backend.redis`` configuration (``redis_args`` attribute)
"""
from platypush.config import Config
if not (args or kwargs):
kwargs = (
Config.get('redis')
or (Config.get('backend.redis') or {}).get('redis_args', {})
or {}
)
kwargs = get_redis_conf()
return Redis(*args, **kwargs)