Pueue

Pueue is a command-line task management tool for sequential and parallel execution of long-running tasks.

Simply put, it's a tool that processes a queue of shell commands. On top of that, there are a lot of convenience features and abstractions.

Since Pueue is not bound to any terminal, you can control your tasks from any terminal on the same machine. The queue will be continuously processed, even if you no longer have any active ssh session.

It provides functionality for:

• Scheduling commands that will be executed in their respective working directories
• Easy output inspection.
• Interaction with running processes
• Pause/Resume resume tasks, when you need some processing power right NOW!
• Manipulation of the scheduled task order
• Running multiple tasks at once (You can decide how many concurrent tasks you want to run)
• Grouping tasks. Each group acts as their own queue and can have several tasks running in parallel.
• A callback hook to, for instance, set up desktop notifications.
• Works on Linux, MacOS and partially on Windows.

Disclaimer: Windows isn't fully supported yet. This means:

• Pausing/resuming commands doesn't work for now.
• Pueue only supports powershell for executing commands, keep this in mind when writing commands.

Why should I use it?

Imagine having to unpack or move large amounts of data to various directories. Usually something like this ends with about 10 open terminals/tmux sessions and an over-challenged hard drive.

A similar scenario would occur, if you want to, for instance, re-encode 10 movies and each re-encode takes 12 hours. Creating a chained command with 10 && isn't ergonomic at all and running 10 re-encodes in parallel will break your CPU.

Pueue is specifically designed for these situations.

You can schedule your task and continue on the same shell without waiting. You can specify how many tasks should run in parallel and even group tasks to maximize system resource utilization. You could log off your server and come back later to check on your tasks' progress.

Heck, you can even set up desktop notifications to get notified or execute parameterized commands as soon as a tasks finishes.

A few possible applications:

• Copying huge amounts of stuff
• Compression tasks
• Movie encoding
• rsync tasks
• Anything that takes longer than 5 minutes

Pueue made at least my life a lot easier on many occasions.

If you like the project, feel free to give it at try!
If you feel like something is missing, please create an issue :).

PRs are of course very welcome!

Installation:

There are three different ways to install Pueue.

Package Manager
Use your system's package manager.
This will usually deploy service files and completions automatically.
Pueue has been packaged for:

• Arch Linux's AUR: e.g. yay -S pueue.
• NixOS
• Homebrew

Via Cargo
You'll need Rust version >=1.39

cargo install pueue

This will install pueue to ~/.cargo/bin/pueue

From Source
You'll need Rust version >=1.39

git clone git@github.com:Nukesor/pueue
cd pueue
cargo install --path .

This will install pueue to ~/.cargo/bin/pueue

Starting the Daemon

Local

Just run pueued anywhere on your commandline. It'll exit if you close the terminal, though.

Background

To fork pueued into the background, add the -d or --daemonize flag. E.g. pueued -d.
The daemon can be then shut down using the client: pueue shutdown

Systemd

If you use Systemd and don't install Pueue with a package manager, place pueued.service in /etc/systemd/user/.
Afterward, every user can start/enable their own session with:

    systemctl --user start pueued.service
    systemctl --user enable pueued.service

How to use it:

Adding Commands:

To add a command just write: pueue add sleep 60
If you want to add flags to the command, you can either:

• add -- => pueue add -- ls -al
• surround the command with a string pueue add 'ls -al'

The command will then be added and scheduled for execution, as if you executed it right now and then.

For normal operation it's recommended to add an alias to your shell's rc.
E.g.: alias pad='pueue add --'

Surrounding a command with quotes is also required, if your command contains escaped characters.
For instance pueue add ls /tmp/long\ path will result in the execution of sh -c ls /tmp/long path, which will then break, as the escaped space is not passed to Pueue.

See what's going on:

To get the status of currently running commands, just type pueue status.

To look at the current output of a command use pueue log or pueue log $task_id.

If you want to follow the output of a running command use git follow $task_id. To follow stderr, use the -e flag.

Pitfalls:

To avoid common pitfalls, please read the FAQ Section.

There is a help option (-h) for all commands.

Pueue client 0.5.0
Arne Beer <contact@arne.beer>
Interact with the Pueue daemon

USAGE:
    pueue [FLAGS] [OPTIONS] <SUBCOMMAND>

FLAGS:
    -h, --help       Prints help information
    -V, --version    Prints version information
    -v, --verbose    Verbose mode (-v, -vv, -vvv)

OPTIONS:
    -p, --port <port>    The port for the daemon. Overwrites the port in the config file

SUBCOMMANDS:
    add            Enqueue a task for execution
    clean          Remove all finished tasks from the list (also clears logs)
    completions    Generates shell completion files. This can be ignored during normal operations
    edit           Edit the command or path of a stashed or queued task.
                   This edits the command of the task by default.
    enqueue        Enqueue stashed tasks. They'll be handled normally afterwards
    follow         Follow the output of a currently running task. This command works like `tail -f`
    group          Manage groups. Without any flags, this will simply display all known groups
    help           Prints this message or the help of the given subcommand(s)
    kill           Kill specific running tasks or various groups of tasks
    log            Display the log output of finished tasks
    parallel       Set the amount of allowed parallel tasks
    pause          Pause either running tasks or specific groups of tasks.
                   Without any parameters, pauses the default queue and all it's tasks.
                   A paused queue (group) won't start any new tasks.
                   Everything can be resumed with `start`.
    remove         Remove tasks from the list. Running or paused tasks need to be killed first
    reset          Kill all running tasks, remove all tasks and reset max_task_id
    restart        Restart task(s). Identical tasks will be created and instantly queued (unless specified
                   otherwise)
    send           Send something to a task. Useful for sending confirmations ('y\n')
    shutdown       Remotely shut down the daemon. Should only be used if the daemon isn't started by a service
                   manager
    start          Resume operation of specific tasks or groups of tasks.
                   Without any parameters, resumes the default queue and all it's tasks.
                   Can also be used force specific tasks to start.
    stash          Stashed tasks won't be automatically started. Either `enqueue` them, to be normally handled or
                   explicitly `start` them
    status         Display the current status of all tasks
    switch         Switches the queue position of two commands. Only works on queued and stashed commands

Configs

The configuration file of Pueue is located in ~/.config/pueue.yml.
The default will be generated after starting pueue once.

---
client:
  daemon_port: "6924"
  secret: "your_secret"
  read_local_logs: true

daemon:
  pueue_directory: /home/$USER/.local/share/pueue
  default_parallel_tasks: 1
  pause_on_failure: false
  port: "6924"
  secret: "your_secret"
  callback: ""Task {{ id }}\nCommand: {{ command }}\nPath: {{ path }}\nFinished with status '{{ result }}'\""
  groups:
    cpu: 1

Client:

• daemon_port The port the client tries to connect to.
• secret The secret, that's used for authentication
• read_local_logs If the client runs as the same user (and on the same machine) as the daemon, logs don't have to be sent via the socket but rather read directly.

Daemon:

• pueue_directory The location Pueue uses for its intermediate files and logs.
• default_parallel_tasks Determines how many tasks should be processed concurrently.
• pause_on_failure If set to true, the daemon stops starting new task as soon as a single task fails. Already running tasks will continue.
• port The port the daemon should listen to.
• secret The secret, that's used for authentication
• callback The command that will be called after a task finishes. Can be parameterized
• groups This is a list of the groups with their amount of allowed parallel tasks. It's advised to not manipulate this manually, but rather use the group subcommand to create and remove groups.

Logs

All logs can be found in ${pueue_directory}/logs. Logs of previous Pueue sessions will be created whenever you issue a reset or clean.
In case the daemon fails or something goes wrong, the daemon will print to stdout/stderr. If the daemon crashes or something goes wrong, please set the debug level to -vvvv and create an issue with the log!

If you want to dig right into it, you can compile and run it yourself with a debug build. This would help me a lot!

Utilities

Groups

Grouping tasks can be useful, whenever your tasks utilize different system resources.
A possible scenario would be to have an io group for tasks that copy large files, while your cpu-heavy (e.g. reencoding) tasks are in a cpu group. The parallelism setting of io could then be set to 1 and cpu be set to 2.

As a result, there'll always be a single task that copies stuff, while two tasks try to utilize your cpu as good as possible.

This removes the problem of scheduling tasks in a way that the system might get slow. At the same time, you're able to maximize resource utilization.

Callbacks

You can specify a callback that will be called every time a task finishes. The callback can be parameterized with some variables.

These are the available variables that can be used to create a command:

• {{ id }}
• {{ command }}
• {{ path }}
• {{ result }} (Success, Killed, etc.)
• {{ group }}

Example callback:

    callback: "notify-send \"Task {{ id }}\nCommand: {{ command }}\nPath: {{ path }}\nFinished with status '{{ result }}'\""

Shell completion files

Shell completion files can be created on the fly with pueue completions $shell $directory. There's also a build_completions.sh script, which creates all completion files in the utiles/completions directory.

JSON Support

The Pueue client status and log commands support JSON output with the -j flag. This can be used to easily incorporate it into window manager bars, such as i3bar.

Scripting

When calling pueue commands in a script, you might need to sleep for a short amount of time for now. The pueue server processes requests asynchronously, whilst the TaskManager runs it's own update loop with a small sleep. (The TaskManager handles everything related to starting, stopping and communicating with processes.)

A sleep in scripts will probably become irrelevant, as soon as this bug in rust-lang is fixed: https://github.com/rust-lang/rust/issues/39364

Copyright © 2019 Arne Beer (@Nukesor)