DeeBee

Go library for storing application state.

Where it can be used?

In all kinds of applications that store their state in RAM and would like to save it to disk - cyclically, on demand or during shutdown. In other words, they would like to save a snapshot of their in-memory data structures to disk and restore them during startup.

Install

go get -u github.com/elgopher/deebee

Quick Start

See example/json/main.go. More examples in example directory. You can also check deebee-loans - an example web application using in-memory state and DeeBee for persistence.

Features:

Atomic write

• either the state is saved completely or not at all
• tolerance for killing the app while writing, restarting the machine or loss of power

Integrity verification while reading

• tolerance for disk problems, buggy drivers or firmware
• tolerance for accidental file altering

Access to historical data

• all previous states are available
• ability to read latest integral file (fail-over to previous version if latest is corrupted)
• API for deleting historical data - on demand or cyclically

Asynchronous replication

• ability to copy latest version of state to another file-system (such as NFS)
• API for reading from multiple replicated stores

Very little use of RAM and CPU

Developer-friendly API

• small API with just a few functions and small amount of production code
• no external dependencies
• extensibility - new data formats can be easily added in a form of custom Codecs

Easy application debugging

• data is stored on disk as it was saved by the app, so it can be easily read using editor of-choice
• data can be updated by hand (when integrity check is disabled or when user also updated the checksum)

Alternatives

• read/write files using standard os package
• use cloud storage services, such as AWS S3

Project status

MVP almost ready. The API is still changing though.