adjust reverse proxy infrastructure to selectively proxy based on host header (#7)

This commit is contained in:
Michael Quigley 2022-07-26 13:30:19 -04:00
parent cad9a2bf5b
commit 0b6469b742
No known key found for this signature in database
GPG Key ID: 9B60314A9DD20A62
2 changed files with 89 additions and 1 deletions

View File

@ -5,6 +5,7 @@ import (
"github.com/openziti/sdk-golang/ziti"
"github.com/openziti/sdk-golang/ziti/config"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
"net/http"
)
@ -18,10 +19,18 @@ func Run(cfg *Config) error {
zTransport := http.DefaultTransport.(*http.Transport).Clone()
zTransport.DialContext = zDialCtx.Dial
proxy, err := util.NewProxy("http://zrok")
proxy, err := util.NewServiceProxy(&resolver{})
if err != nil {
return err
}
proxy.Transport = zTransport
return http.ListenAndServe(cfg.Address, util.NewProxyHandler(proxy))
}
type resolver struct {
}
func (r *resolver) Service(host string) string {
logrus.Infof("host = '%v'", host)
return "zrok"
}

View File

@ -1,12 +1,18 @@
package util
import (
"fmt"
"github.com/sirupsen/logrus"
"net/http"
"net/http/httputil"
"net/url"
"strings"
)
type ProxyServiceResolver interface {
Service(host string) string
}
func NewProxy(target string) (*httputil.ReverseProxy, error) {
targetURL, err := url.Parse(target)
if err != nil {
@ -30,6 +36,24 @@ func NewProxy(target string) (*httputil.ReverseProxy, error) {
return proxy, nil
}
func NewServiceProxy(p ProxyServiceResolver) (*httputil.ReverseProxy, error) {
proxy := hostTargetReverseProxy(p)
director := proxy.Director
proxy.Director = func(req *http.Request) {
director(req)
logrus.Infof("-> %v", req.URL.String())
req.Header.Set("X-Proxy", "zrok")
}
proxy.ModifyResponse = func(resp *http.Response) error {
return nil
}
proxy.ErrorHandler = func(w http.ResponseWriter, r *http.Request, err error) {
logrus.Errorf("error proxying: %v", err)
}
return proxy, nil
}
type proxyHandler struct {
proxy *httputil.ReverseProxy
}
@ -41,3 +65,58 @@ func NewProxyHandler(proxy *httputil.ReverseProxy) *proxyHandler {
func (self *proxyHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
self.proxy.ServeHTTP(w, r)
}
func hostTargetReverseProxy(r ProxyServiceResolver) *httputil.ReverseProxy {
director := func(req *http.Request) {
targetSvc := r.Service(req.Host)
if target, err := url.Parse(fmt.Sprintf("http://%v", targetSvc)); err == nil {
targetQuery := target.RawQuery
req.URL.Scheme = target.Scheme
req.URL.Host = target.Host
req.URL.Path, req.URL.RawPath = joinURLPath(target, req.URL)
if targetQuery == "" || req.URL.RawQuery == "" {
req.URL.RawQuery = targetQuery + req.URL.RawQuery
} else {
req.URL.RawQuery = targetQuery + "&" + req.URL.RawQuery
}
if _, ok := req.Header["User-Agent"]; !ok {
// explicitly disable User-Agent so it's not set to default value
req.Header.Set("User-Agent", "")
}
}
}
return &httputil.ReverseProxy{Director: director}
}
func joinURLPath(a, b *url.URL) (path, rawpath string) {
if a.RawPath == "" && b.RawPath == "" {
return singleJoiningSlash(a.Path, b.Path), ""
}
// Same as singleJoiningSlash, but uses EscapedPath to determine
// whether a slash should be added
apath := a.EscapedPath()
bpath := b.EscapedPath()
aslash := strings.HasSuffix(apath, "/")
bslash := strings.HasPrefix(bpath, "/")
switch {
case aslash && bslash:
return a.Path + b.Path[1:], apath + bpath[1:]
case !aslash && !bslash:
return a.Path + "/" + b.Path, apath + "/" + bpath
}
return a.Path + b.Path, apath + bpath
}
func singleJoiningSlash(a, b string) string {
aslash := strings.HasSuffix(a, "/")
bslash := strings.HasPrefix(b, "/")
switch {
case aslash && bslash:
return a + b[1:]
case !aslash && !bslash:
return a + "/" + b
}
return a + b
}