squeegily/pleroma
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity
be02684579
pleroma/docs/development/config_versioning.md
Alexander Strizhakov be02684579
config versioning 
- added DynamicSupervisor, which starts Pleroma deps and restarts config dependent deps
- added versioning for in database config. New version is created from
changes which are passed to config update/delete endpoint. Every version
contains backup with all changes added through update. Versioning
supports rollbacks with N steps. With a rollback, all versions that
come after the version on which the rollback was made are deleted.
2021-03-16 19:27:24 +03:00

2.0 KiB
Raw Blame History

Config versioning

Database configuration supports simple versioning. Every change (list of changes or only one change) through adminFE creates new version with backup from config table. It is possible to do rollback on N steps (1 by default). Rollback will recreate config table from backup.

IMPORTANT Destructive operations with Pleroma.ConfigDB and Pleroma.Config.Version must be processed through Pleroma.Config.Versioning module for correct versioning work, especially migration changes.

Example:

  • new config setting is added directly using Pleroma.ConfigDB module
  • user is doing rollback and setting is lost

Creating new version

Creating new version is done with Pleroma.Config.Versioning.new_version/1, which accepts list of changes. Changes can include adding/updating/deleting operations in config table at the same time.

Process of creating new version:

  • saving config changes in config table
  • saving new version with current configs
    • backup - keyword with all configs from config table (binary)
    • current - flag, which marks current version (boolean)

Version rollback

Version control also supports a simple N steps back mechanism.

Rollback process:

  • cleaning config table
  • splitting backup field into separate settings and inserting them into config table
  • removing subsequent versions

Config migrations

Sometimes it becomes necessary to make changes to the configuration, which can be stored in the user's database. Config versioning makes this process more complicated, as we also must update this setting in versions backups.

Versioning module contains two functions for migrations:

  • Pleroma.Config.Versioning.migrate_namespace/2 - for simple renaming, e.g. group or key of the setting must be renamed.
  • Pleroma.Config.Versioning.migrate_configs_and_versions/2 - abstract function for more complex migrations. Accepts two functions, the first one to make changes with configs, another to make changes with version backups.