Backdrop - Go Web Framework Agnostic Context Management

Abstract

Context is critical for web applications. Many frameworks solve the context issue by locking you into their framework. This project attempts to provide a clean interface to use net.context within your framework agnostic application.

Design

Global Context Repository protected by goroutine synchronization
Contexts are per request and cancelable
Underlying contexts are net.context.Context

Examples

package main

import (
	"fmt"
	"net/http"
	"time"

	"golang.org/x/net/context"

	"github.com/codegangsta/negroni"
	"github.com/husobee/backdrop"
	"github.com/husobee/vestigo"
	"github.com/satori/go.uuid"
	"github.com/tylerb/graceful"
)

func main() {
	// using negroni for this example to show middlewares can access context
	n := negroni.Classic()
	// start backdrop - here you can provide a backdrop.Options with a base
	// context to inherit from if you choose.
	backdrop.Start(nil)

	// set up awesome router ;)
	router := vestigo.NewRouter()
	router.Get("/:name", f)

	n.Use(&ridMiddleware{})
	// add router to middleware
	n.UseHandler(router)

	// graceful start/stop server
	srv := &graceful.Server{
		Timeout: 5 * time.Second,
		Server: &http.Server{
			Addr: ":1234",
			// top level handler needs to clear the context
			// per each request, use this wrapper handler
			Handler: backdrop.NewClearContextHandler(n),
		},
	}
	srv.ListenAndServe()
}

func f(w http.ResponseWriter, r *http.Request) {
	// get the id from the context
	id, err := backdrop.Get(r, "id")
	if err != nil {
		fmt.Println("err: ", err.Error())
	}
	fmt.Printf("request id is: %v\n", id)
	// you can also get the entire context if you are more comfortable with that
	ctx := backdrop.GetContext(r)
	ctx = context.WithValue(ctx, "key", "value")
	// and setting the newly created context in backdrop
	backdrop.SetContext(r, ctx)
}

type ridMiddleware struct{}

func (rid *ridMiddleware) ServeHTTP(w http.ResponseWriter, r *http.Request, next http.HandlerFunc) {
	// example of setting a value to the context
	backdrop.Set(r, "id", uuid.NewV4())
	next(w, r)
}

Licensing

The MIT License covered under this License.

Contributing

If you wish to contribute, please fork this repository, submit an issue, or pull request with your suggestions.
Please use gofmt and golint before trying to contribute.

husobee / backdrop