clear separation of updater responsibilities vs core responsibilities

[DeepDiver1975]

Background:

• only core and the used apps can tightly manage their upgrade process
• giving the updater a too fine granular control over the individual steps I see us being blocked in the future with respect to enhancing core's mechanism
• finally: core has to upgrade itself properly without the updater app

Updater Responsibilities:

• download new versions
• create checkpoints
• respect upgrade channels
• guide the overall process
• inform the user about the upgrade

Core Responsibilities:

• occ upgrade and ajax/upgrade remain the master entry points for the upgrade process
• the upgrade will be split into the requires more fine granular sub steps:

1. Repair and cleanup (pre upgrade, DB collations update, ..) [danger, might take long]
2. db schema upgrade simulated (optionally, can be done online in advance)
3. disable 3rdparty/no shipped apps
4. db schema upgrade real [danger, might take long]
5. execute core upgrade scripts [danger, might take long]
6. upgrade shipped apps [danger, might take long] - schema migration & app upgrade scripts
7. try reenable, download and upgrade 3rdparty/non shipped apps. (one app after another)
8. repair and cleanup step 1 (post upgrade, repair legacy storage, ..) [danger, might take long]

Will move to core once discussion is final

Core Upgrade Changes:

• occ:upgrade will execute all sub steps
• each step can be executed by itself
• all substeps will be exposed to the updater so that it can call them step by step
• all upgrade steps can be executed even if we are already in maintenance mode
• new method is required to ensure only one upgrade process is triggered

maybe worth an issue on it's own

webui integration of core and updater

• core/ajax/update renders core templates 😠
• updater should consume a json based api to trigger and query for the current processing state
• core's own update ui should consume the json api
• no eventsource please 😠

[DeepDiver1975]

@karlitschek

[karlitschek]

looks good!

[DeepDiver1975]

refs owncloud/core#23913

[ghost]

how does this match with #204? @DeepDiver1975 @karlitschek @VicDeo

[DeepDiver1975]

I will merge the idea into this ticket.

[VicDeo]

@DeepDiver1975 there should be a room for integrity check as well.
Before or After or Before-n-After the process.

If it is done before the upgrade, integrity check cache should be flushed at the end of upgrade.

[VicDeo]

@DeepDiver1975 should substeps be invoked as a parameter passed to
occ upgrade or as a new commands?

[DeepDiver1975]

We will add subtasks of occ upgrade. But this is out of scope for 9.1

[PVince81]

moving to backlog, needs rescheduling and scoping