Jocko

Kafka/distributed commit log service in Go.

Goals of this project:

• Implement Kafka in Go
• Protocol compatible with Kafka so Kafka clients and services work with Jocko
• Make operating simpler
• Distribute a single binary
• Use Serf for discovery, Raft for consensus (and remove the need to run ZooKeeper)
• Smarter configuration settings
  • Able to use percentages of disk space for retention policies rather than only bytes and time kept
  • Handling size configs when you change the number of partitions or add topics
• Learn a lot and have fun

TODO

• Producing
• Fetching
• Partition consensus and distribution
• Protocol
  • Produce
  • Fetch
  • Metadata
  • Create Topics
  • Delete Topics
  • Consumer group [current task]
• Discovery
• API versioning [more API versions to implement]
• Replication [first draft done - testing heavily now]

Hiatus Writing Book

I’m writing a book for PragProg called Building Distributed Services with Go. You can sign up on this mailing list and get updated when the book’s available. It walks you through building a distributed commit log from scratch. I hope it will help Jocko contributors and people who want to work on distributed services.

Reading

• How Jocko's built-in service discovery and consensus works
• How Jocko's (and Kafka's) storage internals work

Project Layout

├── broker        broker subsystem
├── cmd           commands
│   └── jocko     command to run a Jocko broker and manage topics
├── commitlog     low-level commit log implementation
├── examples      examples running/using Jocko
│   ├── cluster   example booting up a 3-broker Jocko cluster
│   └── sarama    example producing/consuming with Sarama
├── protocol      golang implementation of Kafka's protocol
├── prometheus    wrapper around Prometheus' client lib to handle metrics
├── server        API subsystem
└── testutil      test utils
    └── mock      mocks of the various subsystems

Building

Local

1. Clone Jocko

   $ go get github.com/travisjeffery/jocko
   

2. Build Jocko

   $ cd $GOPATH/src/github.com/travisjeffery/jocko
   $ make build
   

   (If you see an error about dep not being found, ensure that$GOPATH/bin is in your PATH)

Docker

docker build -t travisjeffery/jocko:latest .

Contributing

See CONTRIBUTING for details on submitting patches and the contribution workflow.

License

Jocko is under the MIT license, see the LICENSE file for details.

• travisjeffery.com

• GitHub @travisjeffery

• Twitter @travisjeffery

• Medium @travisjeffery