Keyster

Experiments in key/value storage.

Overview

Keyster is a trivial key/value store which talks over UDP.

Requirements

• sglib 1.0.4
• libuv 1.5.0+

Protocol

Commands are sent to the server on socket 6347.

All commands currently follow the same basic format

<cmd><key>[<value>]

All replies follow the same format.

The is a single byte indicating the action:

• X: cause the server to exit.
• G: Get the value for the supplied key
• S: Set a key/value
• A: Add a key/value if key is not set
• D: Delete a key.

Reply commands use the lower case of the request letter.

For commands requiring a Key, it is nul terminated.

For commands sending a Value, its size in inferred from the size of the UDP packet. This practically limits the size of values to (64k - 1 - len(key) - 1).

eXit

Tells the server to exit, discarding all data.

No key or value fields are needed for this.

Get

Returns the value for the given key, if any. If no key exists, no data are returned.

g<key>\x00

Add

Sets the value for the given key ONLY if it does not already have a value.

Returns the key and value

a<key>\x00<value>

Set

Sets the value for the given key, adding it if it doesn't already exist.

Returns the key and value

s<key>\x00<value>

Delete

Deletes the key, returning the value if it existed.

d<key>\x00
d<key>\x00<value>

Internals

Currently the system uses lubuv as an event loop, and a Red-Black tree as implemented by SGLib for key/value storage.