From a05101cce941692f3c025f1777c51e7da2d651bb Mon Sep 17 00:00:00 2001
From: Will McCutchen <will@mccutch.org>
Date: Fri, 1 Apr 2022 18:30:18 -0400
Subject: [PATCH] Add user agent and client IP to instrumentation (#78)
---
httpbin/handlers.go | 14 +++++------
httpbin/helpers.go | 22 ++++++++++++-----
httpbin/helpers_test.go | 53 +++++++++++++++++++++++++++++++++++++++--
httpbin/middleware.go | 28 +++++++++++++---------
4 files changed, 91 insertions(+), 26 deletions(-)
diff --git a/httpbin/handlers.go b/httpbin/handlers.go
index b5dbf64..3ff4ccf 100644
--- a/httpbin/handlers.go
+++ b/httpbin/handlers.go
@@ -51,7 +51,7 @@ func (h *HTTPBin) Get(w http.ResponseWriter, r *http.Request) {
resp := &getResponse{
Args: r.URL.Query(),
Headers: getRequestHeaders(r),
- Origin: getOrigin(r),
+ Origin: getClientIP(r),
URL: getURL(r).String(),
}
body, _ := json.Marshal(resp)
@@ -63,7 +63,7 @@ func (h *HTTPBin) RequestWithBody(w http.ResponseWriter, r *http.Request) {
resp := &bodyResponse{
Args: r.URL.Query(),
Headers: getRequestHeaders(r),
- Origin: getOrigin(r),
+ Origin: getClientIP(r),
URL: getURL(r).String(),
}
@@ -81,7 +81,7 @@ func (h *HTTPBin) RequestWithBody(w http.ResponseWriter, r *http.Request) {
func (h *HTTPBin) Gzip(w http.ResponseWriter, r *http.Request) {
resp := &gzipResponse{
Headers: getRequestHeaders(r),
- Origin: getOrigin(r),
+ Origin: getClientIP(r),
Gzipped: true,
}
body, _ := json.Marshal(resp)
@@ -101,7 +101,7 @@ func (h *HTTPBin) Gzip(w http.ResponseWriter, r *http.Request) {
func (h *HTTPBin) Deflate(w http.ResponseWriter, r *http.Request) {
resp := &deflateResponse{
Headers: getRequestHeaders(r),
- Origin: getOrigin(r),
+ Origin: getClientIP(r),
Deflated: true,
}
body, _ := json.Marshal(resp)
@@ -120,7 +120,7 @@ func (h *HTTPBin) Deflate(w http.ResponseWriter, r *http.Request) {
// IP echoes the IP address of the incoming request
func (h *HTTPBin) IP(w http.ResponseWriter, r *http.Request) {
body, _ := json.Marshal(&ipResponse{
- Origin: getOrigin(r),
+ Origin: getClientIP(r),
})
writeJSON(w, body, http.StatusOK)
}
@@ -502,7 +502,7 @@ func (h *HTTPBin) Stream(w http.ResponseWriter, r *http.Request) {
resp := &streamResponse{
Args: r.URL.Query(),
Headers: getRequestHeaders(r),
- Origin: getOrigin(r),
+ Origin: getClientIP(r),
URL: getURL(r).String(),
}
@@ -716,7 +716,7 @@ func (h *HTTPBin) ETag(w http.ResponseWriter, r *http.Request) {
resp := &getResponse{
Args: r.URL.Query(),
Headers: getRequestHeaders(r),
- Origin: getOrigin(r),
+ Origin: getClientIP(r),
URL: getURL(r).String(),
}
body, _ := json.Marshal(resp)
diff --git a/httpbin/helpers.go b/httpbin/helpers.go
index 366b809..e715752 100644
--- a/httpbin/helpers.go
+++ b/httpbin/helpers.go
@@ -32,13 +32,23 @@ func getRequestHeaders(r *http.Request) http.Header {
return h
}
-func getOrigin(r *http.Request) string {
- forwardedFor := r.Header.Get("X-Forwarded-For")
- if forwardedFor == "" {
- return r.RemoteAddr
+// getClientIP tries to get a reasonable value for the IP address of the
+// client making the request. Note that this value will likely be trivial to
+// spoof, so do not rely on it for security purposes.
+func getClientIP(r *http.Request) string {
+ // Special case some hosting platforms that provide the value directly.
+ if clientIP := r.Header.Get("Fly-Client-IP"); clientIP != "" {
+ return clientIP
}
- // take the first entry in a comma-separated list of IP addrs
- return strings.TrimSpace(strings.SplitN(forwardedFor, ",", 2)[0])
+
+ // Try to pull a reasonable value from the X-Forwarded-For header, if
+ // present, by taking the first entry in a comma-separated list of IPs.
+ if forwardedFor := r.Header.Get("X-Forwarded-For"); forwardedFor != "" {
+ return strings.TrimSpace(strings.SplitN(forwardedFor, ",", 2)[0])
+ }
+
+ // Finally, fall back on the actual remote addr from the request.
+ return r.RemoteAddr
}
func getURL(r *http.Request) *url.URL {
diff --git a/httpbin/helpers_test.go b/httpbin/helpers_test.go
index 0636e0f..931ad9d 100644
--- a/httpbin/helpers_test.go
+++ b/httpbin/helpers_test.go
@@ -3,6 +3,7 @@ package httpbin
import (
"fmt"
"io"
+ "net/http"
"reflect"
"testing"
"time"
@@ -33,7 +34,7 @@ func assertError(t *testing.T, got, expected error) {
}
func TestParseDuration(t *testing.T) {
- var okTests = []struct {
+ okTests := []struct {
input string
expected time.Duration
}{
@@ -61,7 +62,7 @@ func TestParseDuration(t *testing.T) {
})
}
- var badTests = []struct {
+ badTests := []struct {
input string
}{
{"foo"},
@@ -154,3 +155,51 @@ func TestSyntheticByteStream(t *testing.T) {
}
})
}
+
+func Test_getClientIP(t *testing.T) {
+ makeHeaders := func(m map[string]string) http.Header {
+ h := make(http.Header, len(m))
+ for k, v := range m {
+ h.Set(k, v)
+ }
+ return h
+ }
+
+ tests := map[string]struct {
+ given *http.Request
+ want string
+ }{
+ "custom platform headers take precedence": {
+ given: &http.Request{
+ Header: makeHeaders(map[string]string{
+ "Fly-Client-IP": "9.9.9.9",
+ "X-Forwarded-For": "1.1.1.1,2.2.2.2,3.3.3.3",
+ }),
+ RemoteAddr: "0.0.0.0",
+ },
+ want: "9.9.9.9",
+ },
+ "x-forwarded-for is parsed": {
+ given: &http.Request{
+ Header: makeHeaders(map[string]string{
+ "X-Forwarded-For": "1.1.1.1,2.2.2.2,3.3.3.3",
+ }),
+ RemoteAddr: "0.0.0.0",
+ },
+ want: "1.1.1.1",
+ },
+ "remoteaddr is fallback": {
+ given: &http.Request{
+ RemoteAddr: "0.0.0.0",
+ },
+ want: "0.0.0.0",
+ },
+ }
+ for name, tt := range tests {
+ t.Run(name, func(t *testing.T) {
+ if got := getClientIP(tt.given); got != tt.want {
+ t.Errorf("getClientIP() = %v, want %v", got, tt.want)
+ }
+ })
+ }
+}
diff --git a/httpbin/middleware.go b/httpbin/middleware.go
index 5186789..13e937a 100644
--- a/httpbin/middleware.go
+++ b/httpbin/middleware.go
@@ -123,22 +123,26 @@ func observe(o Observer, h http.Handler) http.Handler {
t := time.Now()
h.ServeHTTP(mw, r)
o(Result{
- Status: mw.Status(),
- Method: r.Method,
- URI: r.URL.RequestURI(),
- Size: mw.Size(),
- Duration: time.Since(t),
+ Status: mw.Status(),
+ Method: r.Method,
+ URI: r.URL.RequestURI(),
+ Size: mw.Size(),
+ Duration: time.Since(t),
+ UserAgent: r.Header.Get("User-Agent"),
+ ClientIP: getClientIP(r),
})
})
}
// Result is the result of handling a request, used for instrumentation
type Result struct {
- Status int
- Method string
- URI string
- Size int64
- Duration time.Duration
+ Status int
+ Method string
+ URI string
+ Size int64
+ Duration time.Duration
+ UserAgent string
+ ClientIP string
}
// Observer is a function that will be called with the details of a handled
@@ -149,7 +153,7 @@ type Observer func(result Result)
// format using the given stdlib logger
func StdLogObserver(l *log.Logger) Observer {
const (
- logFmt = "time=%q status=%d method=%q uri=%q size_bytes=%d duration_ms=%0.02f"
+ logFmt = "time=%q status=%d method=%q uri=%q size_bytes=%d duration_ms=%0.02f user_agent=%q client_ip=%s"
dateFmt = "2006-01-02T15:04:05.9999"
)
return func(result Result) {
@@ -161,6 +165,8 @@ func StdLogObserver(l *log.Logger) Observer {
result.URI,
result.Size,
result.Duration.Seconds()*1e3, // https://github.com/golang/go/issues/5491#issuecomment-66079585
+ result.UserAgent,
+ result.ClientIP,
)
}
}
--
GitLab