crush

A time-traveling, replicated, eventually-consistent key-value store.

Warning

Operations are currently NOT atomic! Writing to a key concurrently can and likely will cause issues. You have been warned!

API

GET /:key

Returns the key and its revisions. The returned value looks like:

[current_value, revisions]

where revisions is a possibly-empty list.

If the key does not exist, an empty list is returned:

[]

Query parameters

• revisions: The number of revisions to return. Set to all for all revisions. If this value is not specified, or is not a number or the literal string "all", an empty list of revisions will be returned.
• patch: Whether or not to apply patches. By default, the returned revisions are a set of patches that can be used to revert to each previous state. If patch is set to true, the patches will be applied, and the computed values will be returned as the list of revisions. Defaults to false.

GET /:key/info

Returns info about the given key.

// ▶  curl localhost:7654/test/info
{"key":"test","revision_count":11}

PUT /:key

Sets the value at the given key. The request body is the value that is set. Returns the value that was set.

DELETE /:key

Deletes the key from the store. Returns the following JSON:

{
  "status": "ok",
}

Forks

All of these routes take a :fork parameter, like this:

GET /:key/:fork
PUT /:key/:fork
DELETE /:key/:fork
GET /:key/:fork/info

If you don't provide a fork, the default fork is used.

Forking keys

You can fork a key to operate on a copy of its data without affecting the original. Likewise, you can merge a fork into a target fork.

POST /:key/:fork/fork/:target

// On success
{
  "status": "ok",
}

// On failure
{
  "status": "error",
  "error": "not_found",
}

POST /:key/:fork/merge/:target

Blindly merges the fork's data into the target. This is a destructive operation. You are on your own for rollbacks.

This overwrites the target fork with the provided fork! This does NOT do some sort of smart merge! The originating fork's value OVERWRITES the target fork's value directly, and has the relevant patch added to its history.

// On success
{
  "status": "ok",
}

// On failure
{
  "status": "error",
  "error": "fork_not_found",
}

{
  "status": "error",
  "error": "target_not_found",
}