veloting/valkeyrie

Distributed Key/Value Store Abstraction Library written in Go.

Valkeyrie

valkeyrie provides a Go native library to store metadata using Distributed Key/Value stores (or common databases).

Its goal is to abstract common store operations (Get, Put, List, etc.) for multiple Key/Value store backends.

For example, you can easily implement a generic Leader Election algorithm on top of it (see the docker/leadership repository).

Examples of Usage

You can refer to Examples for a basic overview of the library.

Compatibility

A storage backend in valkeyrie implements (fully or partially) the Store interface.

Calls	Consul	Etcd	Zookeeper	Redis	BoltDB	DynamoDB
Put	✓	✓	✓	✓	✓	✓
Get	✓	✓	✓	✓	✓	✓
Delete	✓	✓	✓	✓	✓	✓
Exists	✓	✓	✓	✓	✓	✓
Watch	✓	✓	✓	✓
WatchTree	✓	✓	✓	✓
NewLock (Lock/Unlock)	✓	✓	✓	✓		✓
List	✓	✓	✓	✓	✓	✓
DeleteTree	✓	✓	✓	✓	✓	✓
AtomicPut	✓	✓	✓	✓	✓	✓
AtomicDelete	✓	✓	✓	✓	✓	✓

Supported Versions

• Consul versions >= 0.5.1 because it uses Sessions with Delete behavior for the use of TTLs (mimics zookeeper's Ephemeral node support), If you don't plan to use TTLs: you can use Consul version 0.4.0+.
• Etcd versions >= 2.0 with APIv2 (deprecated) and >= 3.0 APIv3 (recommended).
• Zookeeper versions >= 3.4.5.
• Redis versions >= 3.2.6. Key space notification needs to be enabled to have access to Watch and Lock methods.
• Boltdb and DynamoDB shouldn't be subject to any version dependencies.

Limitations

Distributed Key/Value stores often have different concepts for managing and formatting keys and their associated values. Even though valkeyrie tries to abstract those stores aiming for some consistency, in some cases it can't be applied easily.

Please refer to the docs/compatibility.md file to see what are the special cases for cross-backend compatibility.

Calls like WatchTree may return different events (or number of events) depending on the backend (for now, Etcd and Consul will likely return more events than Zookeeper that you should triage properly).

Security

Only Consul and etcd have support for secure communication, and you should build and provide your own config.TLS object to feed the client. Support is planned for zookeeper and redis.

Contributing

Want to contribute to valkeyrie? Take a look at the Contribution Guidelines.

The Maintainers.

Copyright and License

Apache License Version 2.0