open-nomad/vendor/github.com/tv42/httpunix/httpunix.go

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2018-09-10 22:08:34 +00:00
// Package httpunix provides a HTTP transport (net/http.RoundTripper)
// that uses Unix domain sockets instead of HTTP.
//
// This is useful for non-browser connections within the same host, as
// it allows using the file system for credentials of both client
// and server, and guaranteeing unique names.
//
// The URLs look like this:
//
// http+unix://LOCATION/PATH_ETC
//
// where LOCATION is translated to a file system path with
// Transport.RegisterLocation, and PATH_ETC follow normal http: scheme
// conventions.
package httpunix
import (
"bufio"
"errors"
"net"
"net/http"
"sync"
"time"
)
// Scheme is the URL scheme used for HTTP over UNIX domain sockets.
const Scheme = "http+unix"
// Transport is a http.RoundTripper that connects to Unix domain
// sockets.
type Transport struct {
DialTimeout time.Duration
RequestTimeout time.Duration
ResponseHeaderTimeout time.Duration
mu sync.Mutex
// map a URL "hostname" to a UNIX domain socket path
loc map[string]string
}
// RegisterLocation registers an URL location and maps it to the given
// file system path.
//
// Calling RegisterLocation twice for the same location is a
// programmer error, and causes a panic.
func (t *Transport) RegisterLocation(loc string, path string) {
t.mu.Lock()
defer t.mu.Unlock()
if t.loc == nil {
t.loc = make(map[string]string)
}
if _, exists := t.loc[loc]; exists {
panic("location " + loc + " already registered")
}
t.loc[loc] = path
}
var _ http.RoundTripper = (*Transport)(nil)
// RoundTrip executes a single HTTP transaction. See
// net/http.RoundTripper.
func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) {
if req.URL == nil {
return nil, errors.New("http+unix: nil Request.URL")
}
if req.URL.Scheme != Scheme {
return nil, errors.New("unsupported protocol scheme: " + req.URL.Scheme)
}
if req.URL.Host == "" {
return nil, errors.New("http+unix: no Host in request URL")
}
t.mu.Lock()
path, ok := t.loc[req.URL.Host]
t.mu.Unlock()
if !ok {
return nil, errors.New("unknown location: " + req.Host)
}
c, err := net.DialTimeout("unix", path, t.DialTimeout)
if err != nil {
return nil, err
}
r := bufio.NewReader(c)
if t.RequestTimeout > 0 {
c.SetWriteDeadline(time.Now().Add(t.RequestTimeout))
}
if err := req.Write(c); err != nil {
return nil, err
}
if t.ResponseHeaderTimeout > 0 {
c.SetReadDeadline(time.Now().Add(t.ResponseHeaderTimeout))
}
resp, err := http.ReadResponse(r, req)
return resp, err
}