Crate pg_taskq

pg-taskq is a simple postgres-based distributed task queue. It is:

• pluggable: install it under a custom schema with custom table names, easily uninstall it again
• simple: in postgres there is 1 table, 1 view, 2 plpgsql functions. In Rust there is a task and worker interface
• async: using tokio
• two-way: task can easily wait on being processed, producing output
• hierarchical: tasks can have sub-tasks that get automatically processed bottom-up

I made this to scratch my own itch to have a flexible, persistent and distributed task queue for various long-running processing tasks without having to maintain additional services and infrastructure. This thing is likely not production ready nor is it battle tested — use at your own risk.

For a worker-producer example see this project.

Structs

• Task
• TaskBuilder
• TaskTableBuilder
  Use this to make TaskTables.
• TaskTables
  TaskTables is used for creating the necessary tables/views/functions in a postgres database. It implements TaskTableProvider and can be passed to crate::Task and crate::Worker that use it for finding out what postgres entities to use.
• Worker

Enums

• Error

Traits

• TaskTableProvider
  Used to make the postgres table/view/function names pluggable. You’ll typically want to use its implementor TaskTables that can be instantiated with a customizable schema and name prefix.
• TaskType
  A TaskType is used to group kinds of tasks. This is useful if you have specialized workers, where one worker only processes on or a few types of tasks. You might also think of it as the “topic”. In the simplest case just use a String or &str. But you can also use a custom enum that implements this trait.

Functions

• connect
• fixup_stale_tasks
  Sets the in_progress flag to false for any tasks that have been in progress for longer than max_allowed_last_update.

Type Aliases

• Result