Changes/Erlang 24

Erlang 24

Summary

Update Erlang/OTP to version 24.

Owner

• Name: Peter Lemenkov, Fedora Erlang SIG, Randy Barlow, Jeremy Cline
• Email: lemenkov@gmail.com, erlang@lists.fedoraproject.org, bowlofeggs@fedoraproject.org, jcline@fedoraproject.org
• Release notes ticket: TBA

Current status

• Targeted release: Fedora 35
• Last updated: 2021-04-03
• FESCo issue: tbd
• Tracker bug: tbd
• Release Notes tracker: tbd

Detailed Description

Upgrade Erlang to version 24 which brings a lot of changes. Just a few highlights:

• New just-in-time compiler.
• Rewritten wx GUI module.
• HiPE module was removed.

Aside from this, we plan to improve quality of Erlang and related packages. These are shortcomings we want to address:

• Every daemon written in Erlang has its own logging solution which doesn't use neither syslog nor Journald. We should start switching them to unified logger..
• We should allow D-Bus API via erlang-dbus library or any other recent implementations..
• Further improve Erlang Packaging Guidelines and promote it as the official guideline.
• Switch to rebar3 as a main build tool.
• SELinux rules for main Erlang applications (Ejabberd, CouchDB, RabbitMQ) are outdated or missing.

Benefit to Fedora

Fedora users, both developers and end-users, will have visible benefits from using Fedora-provided packages. Namely:

• Improved scalability and robustness.

Scope

• Proposal owners:
  • Upgrade Erlang to the latest version (24.0).
  • Every Erlang daemon's systemd unit must require epmd.socket.
  • We need to fill new review request for erlang-dbus
  • Upgrade outdated packages:
    • Riak
      • Riak has has been retired. We have to re-add it back.
    • Ejabberd
    • RabbitMQ.
    • CouchDB
  • rebar3
    • Provide/adjust RPM macros for rebar3.
  • Package GDB macros for easier coredump debugging (see also this ticket).
• Other developers: N/A
• Release engineering: TBA
• Policies and guidelines:
  • We should promote officially Erlang Packaging Guidelines.
• Trademark approval: N/A (not needed for this Change)

Upgrade/compatibility impact

• HiPE was removed completely.

How To Test

• Ensure that high-grade Erlang applications are still working:

Name	Tested
couchdb	No
ejabberd	No
elixir	No
rabbitmq-server	No
riak	No (package was retired :( )
wings	No

• Collect feedback from volunteers regarding their experience with this Erlang/OTP version

User Experience

Users will get more robust, scalable, and fast Erlang applications.

Dependencies

The following packages must be rebuilt: N/A. This time there is no API/ABi change in NIF or Driver API.

Contingency Plan

• Contingency mechanism: None necessary. Instead of falling back to the previous version we should fix existing packages in order to help the Community. We should also monitor upstream development process for potentially discovered issues and proactively apply patches (as we already did with Erlang R14, Erlang R15, Erlang R16, Erlang 17, Erlang 18, Erlang 19, Erlang 20, Erlang 21, Erlang 22, and Erlang 23). It should be noted that this change consists from an independent or loosely coupled smaller changes. If we fail to deliver some changes in time, we should reschedule these exact changes to the future Fedora release while keeping already implemented ones.
• Contingency deadline: N/A
• Blocks release? N/A
• Blocks product? N/A

Documentation

• Erlang/OTP 24.0-rc2 release notes

Release Notes

Erlang/OTP 24.0 is available in Fedora 35.