background_task

Background task with pueue

make nushell "support" background task feature.

Prerequisite

Install pueue and make sure pueued is running with default config, and, pueue is in PATH

Usage

use job.nu

# spawn a new job in background.
> job spawn { sleep 3sec ; echo gg | save gg.txt }

# get job status
> job status

# get one job's log
> job log $job_id

# kill one job
> job kill $job_id

# clean pueued finished job
> job clean

Q&A

How can I pass data to background job?

The easiest way to do is pass it by environment variable, and you can use these variables in job.

So don't do this, it doesn't work:

let a = 3
job spawn {
    echo $a
}

Instead, doing this:

let a = 3
with-env {"a": 3} {
    job spawn {
        echo $env.a
    }
}

But what if I want to pass nushell's structure data to background job?

You can serialize it to env variable, and then deserialize it in background job.

let a = [1, 2, 3]
with-env {"a": ($a | to json)} {
    job spawn {
        let a = ($env.a | from json)
        echo $a
    }
}

How can I reuse custom commands in background job?

You can defined these custom commands in a module, then you can use the module inside the job.

So don't do this, it won't work:

def custom [] { echo 3 }
job spawn {
    custom      # custom is not defined
}

Instead, do this:

# a.nu
export def custom [] { echo 3 }

# main.nu
job spawn {
    use a.nu
    a custom
}