aiomonitor 0.3.1

Installation

Installation process is simple, just:

$ pip install aiomonitor

Example

Monitor has context manager interface:

import aiomonitor

loop = asyncio.get_event_loop()
with aiomonitor.start_monitor(loop=loop):
    loop.run_forever()

Now from separate terminal it is possible to connect to the application:

$ nc localhost 50101

or using included python client:

$ python -m aiomonitor.cli

Tutorial

Lets create simple aiohttp application, and see how aiomonitor can integrates with it.

import asyncio

import aiomonitor
from aiohttp import web

# Simple handler that returns response after 100s
async def simple(request):
    loop = request.app.loop

    print('Start sleeping')
    await asyncio.sleep(100, loop=loop)
    return web.Response(text="Simple answer")

loop = asyncio.get_event_loop()
# create application and register route
app = web.Application(loop=loop)
app.router.add_get('/simple', simple)

# it is possible to pass dictionary with local variables
# to the python console environment
host, port = "localhost", 8090
locals_ = {"port": port, "host": host}
# init monitor just before run_app
with aiomonitor.start_monitor(loop=loop, locals=locals_):
    # run application with built in aiohttp run_app function
    web.run_app(app, port=port, host=host)

Lets save this code in file simple_srv.py, so we can run it with command:

$ python simple_srv.py
======== Running on http://localhost:8090 ========
(Press CTRL+C to quit)

And now one can connect running application from separate terminal, with nc command, immediately aiomonitor will respond with prompt:

$ nc localhost 50101
Asyncio Monitor: 1 tasks running
Type help for commands
monitor >>>

Now you can type commands, for instance help:

monitor >>> help
Commands:
             ps               : Show task table
             where taskid     : Show stack frames for a task
             cancel taskid    : Cancel an indicated task
             signal signame   : Send a Unix signal
             stacktrace       : Print a stack trace from the event loop thread
             console          : Switch to async Python REPL
             quit             : Leave the monitor

aiomonitor supports also async python console inside running event loop so you can explore state of your application:

monitor >>> console
Python 3.5.2 (default, Oct 11 2016, 05:05:28)
[GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.38)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
---
This console is running in an asyncio event loop.
It allows you to wait for coroutines using the 'await' syntax.
Try: await asyncio.sleep(1, result=3, loop=loop)
---
>>> await asyncio.sleep(1, result=3, loop=loop)

To leave console type exit():

>>> exit()
monitor >>>

Requirements

• Python 3.5+

• aioconsole

• uvloop (optional)

0.3.1 (2018-07-03)

• Added the stacktrace command #120 (thanks @agronholm)

0.3.0 (2017-09-08)

• Added _locals_ parameter for passing environment to python REPL

0.2.1 (2016-01-03)

• Fixed import in telnet cli in #12 (thanks @hellysmile)

0.2.0 (2016-01-01)

• Added basic documentation

• Most of methods of Monitor class are not not private api

0.1.0 (2016-12-14)

• Added missed LICENSE file

• Updated API, added start_monitor() function

0.0.3 (2016-12-11)

• Fixed README.rst

0.0.2 (2016-12-11)

• Tests more stable now

• Added simple tutorial to README.rst

0.0.1 (2016-12-10)

• Initial release.