Hystrimp is a Go implementation of Hystrix, an innovative project from Netflix.

Hystrimp/Hystrix provide robustness and resilience in systems with external dependencies, particularly distributed systems (see this excellent introduction). Because the reality of distributed systems is complex, one should never interact with a remote API as if it were composed of local functions. Instead, one should consider important questions such as:

• How long am I willing to wait for the remote system's response?
  • What should I do if I time out before receiving a response?
• What do I do if the remote system responds with an error?
• If a request times out or returns with an error, should I retry it?
  • How many times should I retry the request?
  • How long should I wait before retrying?
• Should I bound the number of parallel requests I make?
• If the remote system is overloaded with requests, is my system part of the problem?
  • How long should my system back off to allow the dependency to recover?

Hystrimp provides a Go implementation of these ideas:

It improves upon hystrix-go (similar project) in the following ways:

• Support for automatic retry of command with backoff upon remote errors or timeouts.
• Remote commands are grouped into logical services
  • Support for concurrency limits on the service as a whole
  • Support for circuit breakers on a service as a whole
• Better ergonomics/interface
• Simpler implementation

1. Install Go
2. Install Godep (go get github.com/tools/godep)
3. Run godep get github.com/Workiva/go-hystrimp/...

When new code is available on master, you can update with go get -u github.com/Workiva/go-hystrimp/...

To run unit tests, do

cd $GOPATH/src/github.com/Workiva/go-hystrimp
godep go test ./...

godep go build -o hystrimp-example -tags example ./example/main
./hystrimp-example

To contribute, do the following:

1. Create a feature branch from master
2. Implement your contributions
3. Ensure unit test coverage
4. Ensure that you've complied with these guidelines
5. gofmt your code
6. Commit with good commit messages
7. Create PR back to master

Bug reports and ideas for improvement are welcome! Please use GitHub's issue tracker.

Tom Deering <tom.deering@workiva.com>