Redis Watchdog

This project allow to monitor Redis keys for changes and launch callbacks.

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Install

$ pip install aioredis-watchdog

Concepts

Redis pattern

You can configure which Redis keys you wish to watch by using a redis pattern.

Callbacks

Each time a key was changed in Redis, aioredis-watchdog will call the list of callbacks.

Using as library

For monitoring all Redis keys that starts by user-:

import asyncio

from aioredis_watchdog import watchdog

async def callback1(key: str, data: bytes):
    print("Key callback 1: ", key, "#", data)

async def callback2(key: str, data: bytes):
    print("Key callback 2: ", key, "#", data)

async def monitoring(connection_string: str):
    redis = await aioredis.create_redis_pool(connection_string)

    callbacks = [callback1, callback2]

    await watchdog("user-*", callbacks, redis)

asyncio.run(monitoring("redis://localhost"))

Callbacks must have this signature:

async def FUNCTION_NAME(KEY: str, VALUE: bytes):
    ...

Where:

• Function is a coroutine
• KEY: is the key name in redis and is plain string
• VALUE: is the value for this key in Redis. It's in bytes format.

You also can config the maximum number of processing packages for watchdog.

In this example only 10 changes will be processed:

...

await watchdog("user-*", callbacks, redis, count=10)

...

Using as CLI

You also can use the library as cli. When you install the package a new command will be available: `redis-watchdog`:

$ redis-watchdog -h

Usage in a pipeline

You can use redis-watchdog in a *NIX pipeline. You only must set the parameter -P to activate it.

At the next step in the pipeline the string "KEY VALUE" will be received. Let me illustrate using an example:

$ redis-watcher -q -P -c 10 | awk '{print $1" ### "$2}'
x6777 ### 80c853a94a0d41ac886ad77ab6441484
x6778 ### afd97f42cbad45a08468e03b3189f753
x6779 ### 26a62f14e9224ed2a429f946a0712f57
x6780 ### b1da88cf24354f77a8ebefc960db1dcc
x6781 ### 2aac5c5f60884025b307f1639ac0392f
x6782 ### 0657604ac8b247e099a6ff1ea7087dc6
x6783 ### f582353a5b3544109fec1a49624fe6bd
x6784 ### 09deb8da158a4ab5bd45d889fb3907b0
x6785 ### 82c8e99b83cf47b0928cabce67a24c54
x6786 ### 541a36e4efee4a65a4c84c95af23ecee
x6787 ### 77c89aaec0e94e588726ab3dbf71a6d4

Oks, let explain the rest of the flags:

• -q to enable quiet mode.
• -P to enable pipeline mode
• -c to limit events to process to 10.

To generate data the script data_producer.py at the examples/ folder was used.

Another example:

Call an end-point by each key:

$ redis-watcher -q -P -c 10 | awk '{print "http://mysite.com/callback?key="$1"&value="$2}' | xargs -n1 wget -O - -q