index.md

Osmos Drivers

Drivers allow Osmos to interface with a specific data store. Because Osmos is store-agnostic, a driver only needs to support a limited number of operations that fit the mould of the typical CRUD system.

Currently, Osmos 1.x supports the following data stores:

• ElasticSearch
• Memory, a memory-based driver useful for testing purposes only.
• MongoDB
• MySQL

CRUD operations

Note that the signatures of these methods have changed as of version 1.1.0

A driver is a class that implements these methods:

• create(model, cb)

  Creates a new document and pass it to the callback. The document should be a simple hash—create's only job is to initialize any arbitrary values that are required by the specific data store.

• get(model, key, cb)

  Retrieves a document from the store. A document-not-found error should be passed to the callback as (null, null).

• post(document, data, cb)

  Inserts a new document into the data store. The data represents the serialized document and, under most circumstances, can be inserted directly into the data store.

  The document argument, which references the Osmos document that is requesting the insertion operation, is also passed along for convenience.

• put(document, data, cb)

  Like post(), but for a document that has already been saved in the past.

• del(model, key, cb)

  Deletes the document with the given key. Document-not-found errors should not result in errors being reported to the callback.

Search operations

In addition to the basic crud operations, a driver should also support these methods:

• findOne(model, query, cb)

  Retrieves any result that matches the given query, represented as a simple hash. There is no prescription as to what query should contain—the meaning is left as an implementation detail for the individual driver.

  A not-found error should be reported as (null, null)

• find(model, spec, cb)

  Retrieves all results that match the given query, returning an array of all the documents that match the query, represented as simple hashes. A not-found error should be reported as (null, []).