Gleam OTP

A Gleam library for building fault tolerant multi-core programs using the actor model. It is compatible with Erlang's OTP framework.

This library is experimental and will likely have many breaking changes in the future!

Actor hierarchy

This library defines several different types of actor that can be used in Gleam programs.

      Process
      ↙    ↘
   Actor   Task
     ↓
Supervisor

Process

The process is the lowest level building block of OTP, all other actors are built on top of processes either directly or indirectly. Typically this abstraction would be not be used very often in Gleam applications, favour other actor types that provide more functionality.

Actor

The actor is the most commonly used actor type in Gleam and serves as a good building block for other abstractions. Like Erlang's gen_server it will automatically handle OTP's debug system messages for you.

Task

A task is a kind of process that performs a single task and then shuts down. Commonly tasks are used to convert sequential code into concurrent code by performing computation in another process.

Supervisor

Supervisors is a process that starts and then supervises a group of processes, restarting them if they crash. Supervisors can start other supervisors, resulting in a hierarchical process structure called a supervision tree, providing fault tolerance to a Gleam application.

Limitations and known issues

This library is experimental there are some limitations that not yet been resolved.

• There is no support for named processes.
• Actors do not yet support all OTP system messages. Unsupported messages are dropped.
• Supervisors do not yet support different shutdown period per child. In practice this means that children that are supervisors do not get an unlimited amount of time to shut down, as is expected in Erlang or Elixir.
• This library has not seen much testing compared to the Erlang OTP libraries, both in terms of unit tests and real world testing in applications.