Trove/extensionsrefactor

Dynamic route proposal

Changes

• Remove existing extensions and move routes mapped into base API app. Ex: instances/<instance_id>/users
• Add code to inspect instance_id and map it to an instance type.. Redis Postgres MySQL etc.
• Have "proxy" route dynamically load a service for each database type either with importlib or stevedore whatever.
• Have the route dynamically accept requests for special edge cases for differing database engines. Ex: Default database for postgres on user create while MySQL does not use one.

Why do it this way?

• Does not change existing API spec. No need to version the API.
• Less cruft in API vs having prefix based user or backup requests. Ex /instances/<instance_id>/mysql/users.
• Generate plugins more quickly and never have routing collisions for new database types. As the request body expected is based off of database type not route.
• Allows for multiple versions or forks of different Database engines more easily. Ex: Allow multiple versions of a Database engine that have differing user create requirements.. (Can't think of anything that exactly matches that scenario so maybe this is a bad example. However, it does allow for differing versions of one database application.)
• Allows the interface for users who only want to support one DB engine to be simplified. Ex: No database type specific URI prefix.
• Allows the base URI mappings to be the same for all databases that have a common type. Ex: users, backups etc.
• Probably less code overall depending on how the prefix specific routes could be added.
• I like this one more =P.

Cons

• Less explicit then using database specific prefixes.

Use a db specific routing methodology

Changes

• Remove existing extensions and move routes mapped into base API app. Ex instances/<instance_id>/<db_type>/users
• Add code to inspect instance_id and verify it's instance type.. Redis Postgres MySQL etc.
• Have "proxy" route dynamically load a service for each database type either with importlib or stevedore whatever.
• Have the route accept requests for differing database engines. Ex. Default database for postgres on user create while MySQL does not use one.

Why do it this way?

• More explicit than dynamic type mapping.
• Might be easier to write docs as each URI is explicit rather than implicit based off of its type.
• Contract is explicit for each URI rather than explicit for database type.
• hub_cap is all about this one!

Cons

• Potential api version change.
• Wonky for Users only using one DB type. The solution to that edge case is to implement a default type for instances/<instance_id> and that is the same as supporting dynamic type resolution essentially.
• Lots of routes to mange depending on how we decide to implement the routing.
• Need to know what type db is in order to know what uri to post to.

Client Examples

Client interaction flow with dynamic type resolution for user add example

• Determine type from instances listing.
• post to instances/<instance_id>/users with db specific body.
• validate input.
• 404 if db does not have concept of users.
• 2** if all is well

Client interaction flow with static db routes for user add example

• Determine type from instance listing.
• post to instances/<instance_id>/<db_type>/users with db specific body.
• validate input.
• 404 if db does not have concept of users.
• 2** if all is well.