Sanic-Synchro-Ctx

Plugin to provide an App context that is shared across multiple workers

Can use native python SyncManager backend, or Redis if you want. (Redis is much faster).

Installation

$ pip3 install sanic-synchro-ctx

Or in a python virtualenv (these example commandline instructions are for a Linux/Unix based OS)

$ python3 -m virtualenv --python=python3 --no-site-packages .venv
$ source ./.venv/bin/activate
$ pip3 install sanic sanic-synchro-ctx

To exit the virtual enviornment:

$ deactivate

Redis Extension

You can install the relevant Redis libraries for this plugin, with the installable redis extension:

$ pip3 install sanic-synchro-ctx[redis]

That is the same as running:

$ pip3 install "sanic-synchro-ctx" "aioredis>=2.0" "hiredis>=1.0"

Compatibility

• Works with Python 3.8 and greater.
• Works with Sanic v21.9.0 and greater.
• If you are installing the redis library separately, use aioredis >= 2.0
• If you have sanic-ext installed, you must use Sanic-Synchro-CTX as an extension (see simple example below).

Usage

A very simple example, it uses the native python SyncManager backend, doesn't require a Redis connection.

from sanic_synchro_ctx import SanicSynchroCtx
app = Sanic("sample")
s = SanicSynchroCtx(app)

@app.after_server_start
def handler(app, loop=None):
    # This will only set this value if it doesn't already exist
    # So only the first worker will set this value
    app.ctx.synchro.set_default({"counter": 0})

@app.route("/inc")
def increment(request: Request):
    # atomic increment operation
    counter = request.app.ctx.synchro.increment("counter")
    print("counter: {}".format(counter), flush=True)
    return html("<p>Incremented!</p>")

@app.route("/count")
def increment(request: Request):
    # Get from shared context:
    counter = request.app.ctx.synchro.counter
    print("counter: {}".format(counter), flush=True)
    return html(f"<p>count: {counter}</p>")

app.run("127.0.0.1", port=8000, workers=8)

Note: If you have Sanic-ext installed, you must use Sanic-Synchro-CTX in conjunction with Sanic-ext

Sanic-ext example:

from sanic_ext import Extend
from sanic_synchro_ctx import SanicSynchroCtx

app = Sanic("simple")
Extend(app, extensions=[SanicSynchroCtx])

@app.after_server_start
def handler(app, loop=None):
    # This will only set this value if it doesn't already exist
    # So only the first worker will set this value
    app.ctx.synchro.set_default({"counter": 0})

@app.route("/")
def index(request: Request):
    counter = request.app.ctx.synchro.increment("counter")

    print("counter: {}".format(counter), flush=True)
    return html("<p>Hello World</p>")

app.run("127.0.0.1", port=8000, workers=8)

Redis example:

from sanic_synchro_ctx import SanicSynchroCtx
redis = aioredis.from_url("redis://localhost")
app = Sanic("sample")
s = SanicSynchroCtx(app, backend="redis", redis_client=redis)

@app.after_server_start
async def handler(app, loop=None):
    # This will only set this value if it doesn't already exist
    # So only the first worker will set this value
    await app.ctx.synchro.set_default({"counter": 0})

@app.route("/inc")
async def increment(request: Request):
    # atomic increment operation
    counter = await request.app.ctx.synchro.increment("counter")
    print(f"counter: {counter}", flush=True)
    return html("<p>Incremented!</p>")

@app.route("/count")
async def increment(request: Request):
    # Get from shared context:
    counter = await request.app.ctx.synchro.counter
    print(f"counter: {counter}", flush=True)
    return html(f"<p>count: {counter}</p>")

app.run("127.0.0.1", port=8000, workers=8)

Changelog

A comprehensive changelog is kept in the CHANGELOG file.

Benchmarks

I've done some basic benchmarks. SyncManager works surprisingly well, but Redis backend is much faster.

License

This repository is licensed under the MIT License. See the LICENSE deed for details.