Oxy 
Oxy is a Go library with HTTP handlers that enhance HTTP standard library:
- Buffer retries and buffers requests and responses
- Stream passes-through requests, supports chunked encoding with configurable flush interval
- Forward forwards requests to remote location and rewrites headers
- Roundrobin is a round-robin load balancer
- Circuit Breaker Hystrix-style circuit breaker
- Connlimit Simultaneous connections limiter
- Ratelimit Rate limiter (based on tokenbucket algo)
- Trace Structured request and response logger
It is designed to be fully compatible with http standard library, easy to customize and reuse.
Status
- Initial design is completed
- Covered by tests
- Used as a reverse proxy engine in Vulcand
Quickstart
Every handler is http.Handler, so writing and plugging in a middleware is easy. Let us write a simple reverse proxy as an example:
Simple reverse proxy
import (
"net/http"
"github.com/vulcand/oxy/forward"
"github.com/vulcand/oxy/testutils"
)
// Forwards incoming requests to whatever location URL points to, adds proper forwarding headers
fwd, _ := forward.New()
redirect := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
// let us forward this request to another server
req.URL = testutils.ParseURI("http://localhost:63450")
fwd.ServeHTTP(w, req)
})
// that's it! our reverse proxy is ready!
s := &http.Server{
Addr: ":8080",
Handler: redirect,
}
s.ListenAndServe()
As a next step, let us add a round robin load-balancer:
import (
"net/http"
"github.com/vulcand/oxy/forward"
"github.com/vulcand/oxy/roundrobin"
)
// Forwards incoming requests to whatever location URL points to, adds proper forwarding headers
fwd, _ := forward.New()
lb, _ := roundrobin.New(fwd)
lb.UpsertServer(url1)
lb.UpsertServer(url2)
s := &http.Server{
Addr: ":8080",
Handler: lb,
}
s.ListenAndServe()
What if we want to handle retries and replay the request in case of errors? buffer handler will help:
import (
"net/http"
"github.com/vulcand/oxy/forward"
"github.com/vulcand/oxy/buffer"
"github.com/vulcand/oxy/roundrobin"
)
// Forwards incoming requests to whatever location URL points to, adds proper forwarding headers
fwd, _ := forward.New()
lb, _ := roundrobin.New(fwd)
// buffer will read the request body and will replay the request again in case if forward returned status
// corresponding to nework error (e.g. Gateway Timeout)
buffer, _ := buffer.New(lb, buffer.Retry(`IsNetworkError() && Attempts() < 2`))
lb.UpsertServer(url1)
lb.UpsertServer(url2)
// that's it! our reverse proxy is ready!
s := &http.Server{
Addr: ":8080",
Handler: buffer,
}
s.ListenAndServe()