https://github.com/0ekk/shell-sched

Simple concurrent task scheduler based on shell and few GNU tools
https://github.com/0ekk/shell-sched

bash concurrent scheduler

Last synced: 2 months ago
JSON representation

Simple concurrent task scheduler based on shell and few GNU tools

README

shell-sched is a simple concurrent task scheduler based on shell and few GNU tools.

## Features

- Concurrent and asynchronous
- Priority based schedule
- Dynamic tuning and slow start
- Less intrusion

[![quick_start_image](./demo.gif)](https://asciinema.org/a/597018)

## Important

The scheduler can only be enabled when SCHED_ENABLED=1 (default).

If not, all task emited run serially as normal rather than exit with error.

## Usage example
If you want sleep 10 seconds in background:

# Import all things of sched.sh into current shell proccess.
source sched.sh

# Startup scheduler
sched::startup

# Emit a task to scheduler
sched::emit "sleep 10"

# Block current proccess for waiting tasks. Optional, if absent, tasks have still be running in background
sched::wait_all_tasks

# Shutdown scheduler
sched::shutdown

## Exposed environment variables
1. SCHED_ENABLED

Enable or disable scheduler

1 -> enable, 0 -> disable

2. SCHED_DATA_ROOT

Root path that stored intermediate data on runtime. Default is under /tmp that is generated automaticlly by runtime.

3. SCHED_MAX_RUNNERS

Max parrallel task counts. Must be great than 0. Default (2 * cpu cores)

4. SCHED_DEBUG

Enable or disable scheduler debug log

1 -> enable, 0 -> disable

# Exposed functions show as below:
1. sched::startup

Start scheduler

2. sched::shutdown

Stop scheduler

3. sched::emit \ [\]

Emit a task to scheduler which would select a task to execute asynchronously based on its priority

Note: task must be a function or one-line command

4. sched::wait_all_tasks_and_exit

Wait all tasks complete or any error occurred, and exit the calling proceess

5. sched::wait_all_tasks

Wait all tasks complete or any error occurred, only exit the calling proccess when error occurred