lib/controller/handler.go

   1 // Copyright (C) The Arvados Authors. All rights reserved.
   2 //
   3 // SPDX-License-Identifier: AGPL-3.0
   4
   5 package controller
   6
   7 import (
   8         "context"
   9         "io"
  10         "net"
  11         "net/http"
  12         "net/url"
  13         "strings"
  14         "sync"
  15         "time"
  16
  17         "git.curoverse.com/arvados.git/sdk/go/arvados"
  18         "git.curoverse.com/arvados.git/sdk/go/health"
  19         "git.curoverse.com/arvados.git/sdk/go/httpserver"
  20 )
  21
  22 type Handler struct {
  23         Cluster     *arvados.Cluster
  24         NodeProfile *arvados.NodeProfile
  25
  26         setupOnce    sync.Once
  27         handlerStack http.Handler
  28         proxyClient  *arvados.Client
  29 }
  30
  31 func (h *Handler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
  32         h.setupOnce.Do(h.setup)
  33         h.handlerStack.ServeHTTP(w, req)
  34 }
  35
  36 func (h *Handler) CheckHealth() error {
  37         h.setupOnce.Do(h.setup)
  38         _, err := findRailsAPI(h.Cluster, h.NodeProfile)
  39         return err
  40 }
  41
  42 func (h *Handler) setup() {
  43         mux := http.NewServeMux()
  44         mux.Handle("/_health/", &health.Handler{
  45                 Token:  h.Cluster.ManagementToken,
  46                 Prefix: "/_health/",
  47         })
  48         mux.Handle("/", http.HandlerFunc(h.proxyRailsAPI))
  49         h.handlerStack = mux
  50 }
  51
  52 // headers that shouldn't be forwarded when proxying. See
  53 // https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers
  54 var dropHeaders = map[string]bool{
  55         "Connection":          true,
  56         "Keep-Alive":          true,
  57         "Proxy-Authenticate":  true,
  58         "Proxy-Authorization": true,
  59         "TE":                true,
  60         "Trailer":           true,
  61         "Transfer-Encoding": true,
  62         "Upgrade":           true,
  63 }
  64
  65 func (h *Handler) proxyRailsAPI(w http.ResponseWriter, reqIn *http.Request) {
  66         urlOut, err := findRailsAPI(h.Cluster, h.NodeProfile)
  67         if err != nil {
  68                 httpserver.Error(w, err.Error(), http.StatusInternalServerError)
  69                 return
  70         }
  71         urlOut = &url.URL{
  72                 Scheme:   urlOut.Scheme,
  73                 Host:     urlOut.Host,
  74                 Path:     reqIn.URL.Path,
  75                 RawPath:  reqIn.URL.RawPath,
  76                 RawQuery: reqIn.URL.RawQuery,
  77         }
  78
  79         // Copy headers from incoming request, then add/replace proxy
  80         // headers like Via and X-Forwarded-For.
  81         hdrOut := http.Header{}
  82         for k, v := range reqIn.Header {
  83                 if !dropHeaders[k] {
  84                         hdrOut[k] = v
  85                 }
  86         }
  87         xff := reqIn.RemoteAddr
  88         if xffIn := reqIn.Header.Get("X-Forwarded-For"); xffIn != "" {
  89                 xff = xffIn + "," + xff
  90         }
  91         hdrOut.Set("X-Forwarded-For", xff)
  92         hdrOut.Add("Via", reqIn.Proto+" arvados-controller")
  93
  94         ctx := reqIn.Context()
  95         if timeout := h.Cluster.HTTPRequestTimeout; timeout > 0 {
  96                 var cancel context.CancelFunc
  97                 ctx, cancel = context.WithDeadline(ctx, time.Now().Add(time.Duration(timeout)))
  98                 defer cancel()
  99         }
 100
 101         reqOut := (&http.Request{
 102                 Method: reqIn.Method,
 103                 URL:    urlOut,
 104                 Header: hdrOut,
 105                 Body:   reqIn.Body,
 106         }).WithContext(ctx)
 107         resp, err := arvados.InsecureHTTPClient.Do(reqOut)
 108         if err != nil {
 109                 httpserver.Error(w, err.Error(), http.StatusInternalServerError)
 110                 return
 111         }
 112         for k, v := range resp.Header {
 113                 for _, v := range v {
 114                         w.Header().Add(k, v)
 115                 }
 116         }
 117         w.WriteHeader(resp.StatusCode)
 118         n, err := io.Copy(w, resp.Body)
 119         if err != nil {
 120                 httpserver.Logger(reqIn).WithError(err).WithField("bytesCopied", n).Error("error copying response body")
 121         }
 122 }
 123
 124 // For now, findRailsAPI always uses the rails API running on this
 125 // node.
 126 func findRailsAPI(cluster *arvados.Cluster, np *arvados.NodeProfile) (*url.URL, error) {
 127         hostport := np.RailsAPI.Listen
 128         if len(hostport) > 1 && hostport[0] == ':' && strings.TrimRight(hostport[1:], "0123456789") == "" {
 129                 // ":12345" => connect to indicated port on localhost
 130                 hostport = "localhost" + hostport
 131         } else if _, _, err := net.SplitHostPort(hostport); err == nil {
 132                 // "[::1]:12345" => connect to indicated address & port
 133         } else {
 134                 return nil, err
 135         }
 136         proto := "http"
 137         if np.RailsAPI.TLS {
 138                 proto = "https"
 139         }
 140         return url.Parse(proto + "://" + hostport)
 141 }