/
proxy.go
137 lines (109 loc) · 3.01 KB
/
proxy.go
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package srv
import (
"context"
"crypto/tls"
"io"
"net/http"
"net/url"
"strings"
"time"
"github.com/google/uuid"
"go.uber.org/zap"
)
var (
sanitizeHeaders = []string{"www-authenticate", "server"}
)
type proxy struct {
origin *Origin
logger *zap.Logger
}
func (s *Server) newProxy(origin *Origin, logger *zap.Logger) *proxy {
return &proxy{
origin: origin,
logger: logger,
}
}
// proxyRequest proxies requests to a given backend
func (p *proxy) proxyRequest(w http.ResponseWriter, r *http.Request) {
requestID, _ := uuid.NewUUID()
ctx := context.WithValue(r.Context(), "requestID", requestID.String())
logger := p.logger.With(
zap.String("req.url", r.URL.String()),
zap.String("http.method", r.Method),
zap.String("request.id", requestID.String()),
)
u, err := url.Parse(p.origin.BaseUrl + r.URL.String())
if err != nil {
logger.Error("failed to parse backend url", zap.Error(err))
}
logger.Debug("proxying request", zap.String("backend.url", u.String()))
req, err := http.NewRequestWithContext(ctx, r.Method, u.String(), r.Body)
if err != nil {
logger.Error("failed to generate backend request", zap.Error(err))
}
// clone headers from request
// TODO sanitize headers for backend
req.Header = r.Header.Clone()
// override headers
for k, v := range p.origin.SetHeaders {
req.Header.Set(k, v)
}
// append headers
for k, v := range p.origin.AddHeaders {
req.Header.Add(k, v)
}
if p.origin.BasicAuth != nil {
logger.Debug("setting basic auth")
req.SetBasicAuth(p.origin.BasicAuth.Username, p.origin.BasicAuth.Password)
}
req.Header.Set("X-Forwarded-For", r.RemoteAddr)
req.Header.Set("X-Forwarded-Proto", r.Proto)
tr := &http.Transport{}
if p.origin.Insecure {
tr.TLSClientConfig = &tls.Config{InsecureSkipVerify: true}
}
client := &http.Client{
CheckRedirect: func(req *http.Request, via []*http.Request) error {
return http.ErrUseLastResponse
},
Timeout: 180 * time.Second,
Transport: tr,
}
resp, err := client.Do(req)
if err != nil {
logger.Warn("failed to proxy request to backend", zap.Error(err))
w.WriteHeader(http.StatusServiceUnavailable)
w.Write([]byte("backend unavailable"))
return
}
defer resp.Body.Close()
p.cloneHeaders(ctx, w, resp)
logger.Debug("returning response code", zap.Int("code", resp.StatusCode))
w.WriteHeader(resp.StatusCode)
io.Copy(w, resp.Body)
}
func (p *proxy) cloneHeaders(ctx context.Context, w http.ResponseWriter, resp *http.Response) {
requestID, ok := ctx.Value("requestID").(string)
if !ok {
requestID = ""
}
logger := p.logger.With(
zap.String("request.id", requestID),
)
for key, values := range resp.Header {
for _, v := range values {
var skip bool
for _, k := range sanitizeHeaders {
if strings.ToLower(k) == strings.ToLower(key) {
skip = true
}
}
if skip {
logger.Debug("sanitizing header", zap.String("key", key), zap.String("value", v))
continue
}
logger.Debug("cloning header", zap.String("key", key), zap.String("value", v))
w.Header().Set(key, v)
}
}
}