forked from flynn-archive/strowger
/
http.go
335 lines (303 loc) · 7.19 KB
/
http.go
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package main
import (
"crypto/tls"
"errors"
"io"
"log"
"math/rand"
"net"
"net/http"
"net/http/httputil"
"path"
"strconv"
"strings"
"sync"
"time"
"github.com/coreos/go-etcd/etcd"
"github.com/flynn/go-discover/discover"
)
type HTTPFrontend struct {
Addr string
TLSAddr string
TLSConfig *tls.Config
mtx sync.RWMutex
domains map[string]*httpServer
services map[string]*httpServer
etcdPrefix string
etcd *etcd.Client
discover *discover.Client
}
func NewHTTPFrontend(addr string) (*HTTPFrontend, error) {
f := &HTTPFrontend{
Addr: addr,
etcd: etcd.NewClient(nil),
etcdPrefix: "/strowger/http/",
domains: make(map[string]*httpServer),
services: make(map[string]*httpServer),
}
var err error
f.discover, err = discover.NewClient()
return f, err
}
func (s *HTTPFrontend) AddHTTPDomain(domain string, service string, certs [][]byte, key []byte) error {
return s.addDomain(domain, service, true)
}
func (s *HTTPFrontend) addDomain(domain string, service string, persist bool) error {
s.mtx.Lock()
defer s.mtx.Unlock()
if server, ok := s.domains[domain]; ok {
if server.name != service {
return errors.New("domain exists with different service")
}
return nil
}
server := s.services[service]
if server == nil {
services, err := s.discover.Services(service)
if err != nil {
return err
}
server = &httpServer{name: service, services: services}
}
if persist {
_, ok, err := s.etcd.TestAndSet(s.etcdPrefix+domain+"/service", "", service, 0)
if err != nil {
return err
}
if !ok {
return errors.New("domain already exists in etcd")
}
}
// TODO: set cert/key data if provided
server.refs++
s.domains[domain] = server
s.services[service] = server
// TODO: TLS config
log.Println("Add service", service, "to domain", domain)
return nil
}
func (s *HTTPFrontend) RemoveHTTPDomain(domain string) {
s.mtx.Lock()
defer s.mtx.Unlock()
server := s.domains[domain]
if server == nil {
return
}
delete(s.domains, domain)
server.refs++
if server.refs <= 0 {
// TODO: close service set stream
delete(s.services, server.name)
}
// TODO: persist
}
func (s *HTTPFrontend) syncDatabase() {
data, err := s.etcd.Get(s.etcdPrefix)
if e, ok := err.(etcd.EtcdError); ok && e.ErrorCode == 100 {
// key not found, ignore
err = nil
}
if err != nil {
log.Fatal(err)
return
}
for _, res := range data {
if !res.Dir {
continue
}
domain := path.Base(res.Key)
serviceRes, err := s.etcd.Get(res.Key + "/service")
if err != nil {
log.Fatal(err)
}
if len(serviceRes) != 1 {
continue
}
service := serviceRes[0].Value
if err := s.addDomain(domain, service, false); err != nil {
log.Fatal(err)
}
}
var since uint64
if len(data) > 0 {
since = data[len(data)-1].Index
}
stream := make(chan *etcd.Response)
stop := make(chan bool)
// TODO: store stop
go s.etcd.Watch(s.etcdPrefix, since, stream, stop)
for res := range stream {
if !res.Dir && res.NewKey && path.Base(res.Key) == "service" {
domain := path.Base(path.Dir(res.Key))
if err := s.addDomain(domain, res.Value, false); err != nil {
// TODO: log error
}
}
// TODO: handle delete
}
log.Println("done watching etcd")
}
func (s *HTTPFrontend) serve() {
l, err := net.Listen("tcp", s.Addr)
if err != nil {
// TODO: log error
return
}
for {
conn, err := l.Accept()
if err != nil {
// TODO: log error
break
}
go s.handle(conn)
}
}
func (s *HTTPFrontend) serveTLS() {
l, err := net.Listen("tcp", s.TLSAddr)
if err != nil {
// TODO: log error
return
}
for {
conn, err := l.Accept()
if err != nil {
// TODO: log error
break
}
go s.handle(conn)
}
}
func (s *HTTPFrontend) handle(conn net.Conn) {
defer conn.Close()
sc := httputil.NewServerConn(conn, nil)
req, err := sc.Read()
if err != nil {
if err != httputil.ErrPersistEOF {
// TODO: log error
}
return
}
s.mtx.RLock()
// TODO: handle wildcard domains
backend := s.domains[req.Host]
s.mtx.RUnlock()
log.Println(req, backend)
if backend == nil {
// TODO: return 404
return
}
_, tls := conn.(*tls.Conn)
backend.handle(req, sc, tls)
}
type httpServer struct {
name string
services *discover.ServiceSet
refs int
}
func (s *httpServer) getBackend() *httputil.ClientConn {
for _, addr := range shuffle(s.services.OnlineAddrs()) {
// TODO: set connection timeout
backend, err := net.Dial("tcp", addr)
if err != nil {
// TODO: log error
// TODO: limit number of backends tried
// TODO: temporarily quarantine failing backends
log.Println("backend error", err)
continue
}
return httputil.NewClientConn(backend, nil)
}
// TODO: log no backends found error
return nil
}
func (s *httpServer) handle(req *http.Request, sc *httputil.ServerConn, tls bool) {
req.Header.Set("X-Request-Start", strconv.FormatInt(time.Now().UnixNano()/int64(time.Millisecond), 10))
backend := s.getBackend()
if backend == nil {
// TODO: Return 503
log.Println("no backend found")
return
}
defer backend.Close()
for {
if req.Method != "GET" && req.Method != "POST" && req.Method != "HEAD" &&
req.Method != "OPTIONS" && req.Method != "PUT" && req.Method != "DELETE" && req.Method != "TRACE" {
// TODO: return 405
}
req.Proto = "HTTP/1.1"
req.ProtoMajor = 1
req.ProtoMinor = 1
delete(req.Header, "Te")
delete(req.Header, "Transfer-Encoding")
if clientIP, _, err := net.SplitHostPort(req.RemoteAddr); err == nil {
// If we aren't the first proxy retain prior
// X-Forwarded-For information as a comma+space
// separated list and fold multiple headers into one.
if prior, ok := req.Header["X-Forwarded-For"]; ok {
clientIP = strings.Join(prior, ", ") + ", " + clientIP
}
req.Header.Set("X-Forwarded-For", clientIP)
}
if tls {
req.Header.Set("X-Forwarded-Proto", "https")
} else {
req.Header.Set("X-Forwarded-Proto", "http")
}
// TODO: Set X-Forwarded-Port
if err := backend.Write(req); err != nil {
log.Println("server write err:", err)
return
}
res, err := backend.Read(req)
if res != nil {
if err := sc.Write(req, res); err != nil {
if err != io.EOF && err != httputil.ErrPersistEOF {
log.Println("client write err:", err)
// TODO: log error
}
return
}
}
if err != nil {
if err != io.EOF && err != httputil.ErrPersistEOF {
log.Println("server read err:", err)
// TODO: log error
// TODO: Return 502
}
return
}
// TODO: Proxy HTTP CONNECT? (example: Go RPC over HTTP)
if res.StatusCode == http.StatusSwitchingProtocols {
serverW, serverR := backend.Hijack()
clientW, clientR := sc.Hijack()
defer serverW.Close()
done := make(chan struct{})
go func() {
serverR.WriteTo(clientW)
close(done)
}()
clientR.WriteTo(serverW)
<-done
return
}
// TODO: http pipelining
req, err = sc.Read()
if err != nil {
if err != io.EOF && err != httputil.ErrPersistEOF {
log.Println("client read err:", err)
}
return
}
req.Header.Set("X-Request-Start", strconv.FormatInt(time.Now().UnixNano()/int64(time.Millisecond), 10))
}
}
func shuffle(s []string) []string {
for i := len(s) - 1; i > 0; i-- {
j := rand.Intn(i + 1)
s[i], s[j] = s[j], s[i]
}
return s
}
func init() {
rand.Seed(time.Now().UnixNano())
}