ACONS

An asynchronous command-line runner for use in async web-servers like fastapi.

Sometimes, you want to run command-line utilities and expose the output to a web-server. However, it's a bit tricky to capture the console output while it's running, and also allow the web-client to kill the job mid-process.

acons can execute command-line processes as an async function, where output can be retrieved via another async function, and a kill signal can be sent at any time.

Install

pip install acons

run

Function interface:

run(command, run_dir=None, is_parse=False, job_id=None)

• command: str of command-line command
• run_dir: optional starting directory of the command
• is_parse: optional flag to parse the output as tsv file into a list of dictionaries
• job_id: optional id that will be used to flush_lines and kill_job

To use in an async function:

await acons.run('ls', job_id='my-special-id-123')

To test the output in a sync version:

import acons
output = acons.sync_run('ls')

flush_lines

In an async function:

lines = await acons.flush_lines('my-special-id-123')

This will return the console lines produced by the job since the last call to acons.flush_lines

kill_job

In an async function:

`await kill_job('my-special-id-123')

Sends the kill signal for the job.

Parameters d

acons.RUN_INTERVAL_IN_S = 0.2 - determines how long the function polls for each interval

acons.SLEEP_INTERVAL_IN_S = 0.5 - determines how long the function sleeps between intervals

acons.N_MAX_JOB = 100 - maximum number of jobs that stores output using an LRU cache

Example server

A simple fastapi-server/vue-client is included that demonstrates acons in action.

Concurrent command-line commands can be typed in and executed. The console output will be piped back into the web-client, and the job can be cancelled at any time.

When the job is completed, the entire console output is made available through the Monaco web-editor .

Download the .zip version of this package, then run the server:

./test-server.sh

which is essentially:

uvicorn server:app --reload --port=5200

Communication between client/server is via an rpc-json interface as described in rpcseed.