distkv 0.65.0

A distributed no-master key-value store

Welcome to DistKV!

DistKV is a master-less distributed key-value storage system. It circumvents the CAP theorem by assuming that keys are usually only changed by one node. It is resistant to partitioning and intended to be always-on; it might delay – but will not lose – updates even in a partitioned network.

DistKV comes with several batteries included:

• Basic user management, pattern-based ACLs

• Strong typing, code- and/or JSON Schema-based

• Data mangling

• Background code execution

• Seamless recovery even if only one master is running

• a MQTT 3.1 back-end that stores persistent data in DistKV, based on hbmqtt

API

DistKV offers an efficient msgpack-based interface to access data and to change internal settings. Most configuration is stored inside DistKV itself.

Stored data are not forced to be strings or binary sequences, but can be anything that MsgPack supports. Keys to storage are multi-level and support string, integer/float, and list keys.

Non-Features

DistKV does not support data partitioning. Every node stores the whole data set and can instantly deliver mostly-uptodate data.

DistKV does not have a disk-based storage backend; periodic snapshots and event logs can be used to quickly restore a system, if necessary.

Status

DistKV is mostly stable. There are a lot of corner cases that don’t have tests yet

TODOs: * some services (esp. command line tools and runners) are under-tested * there’s no good API for errors

Changelog

0.41: the message monitor can do multiple subpaths and only reports initial-load-complete once

0.40: use asyncscope for running subsystems in a reasonable way

0.35: allow forgetting nodes (if they have no data attached)

0.30: major API refactoring: paths are now separate objects

TODO

• update the whole ecosystem to anyio 2.0 (asyncclick asyncscope …)

• clean up some of the more egregious command line mistakes

• create a page for showcase-ing subprojects (distinv knx owfs akumuli …)

• improve Home Assistant integration