Drupal and MongoDB or the road to APIs

Drupal 7

What went well? Entity-field storage: node, comment, user... Session (frequent writes) Watchdog (capped collection) Cache

What worked out so-so? Blocks. Unmaintainable solution.

Where were things stored? List of modules: system table Date formats: date_format_type date_formats date_format_locale tables Text formats: filter filter_format tables Arbitrary contrib arbitrary table

How were things handled? Field widgets, formatters: Some info hook settings stored in an arbitrary table handled by arbitrary callbacks Cache, query: variable_get defines include file variable_get defines settings

Consequences Even with a SQL abstraction driver, full MongoDB is practically impossible. Pluggability is totally arbitrary

Drupal 8 There can be only one

Where are things stored? List of modules: CMI Date formats: CMI Text formats: CMI Arbitrary contrib: CMI or bust

How are things handled? Defined in a dependency injection container: easy and uniform to change Annotated classes: every kind of plugin has the same metadata definition Again, settings in CMI

So how will MongoDB fit? Inject via the DIC Sweep up the remaining little via a DB driver, but this is limited.

MongoDB distribution Necessary to be able to install without MySQL Ability to change things early and keep them changed

Existing drivers? Session: might become Symfony, then needs new driver Watchdog: this might change to Monolog or PSR-3. Entity storage: hopefully base entity storage also (I will work on this)

New drivers File usage Flood

CMI "driver" CMI canonical is YAML file Plus caching We have a cache driver For speed on queries, do not serialize on cache_config (other bins might have objects/arrays so serialize needed)