caddyhttp: Split up remote address into IP and port

Closes #4396, related to #4148

This is a breaking change, but we're already planning on removing  the`common_log` field as well at the same time, so might as well all do it together.

In general, the remote IP is the useful part of the remote address. The port is rarely useful, because it only identifies ephemeral information about the connection from the client. But we were logging both in one field, so certain tooling that would want to only get the remote IP would need to split it up. Splitting is non-trivial, because of IPv4, IPv6, shenanigans. So it's best if we split it up-front before logging. If the log consumer actually cares about the remote port, it can re-assemble it.

admin.go

@@ -659,11 +659,17 @@ type adminHandler struct {
 // ServeHTTP is the external entry point for API requests.
 // It will only be called once per request.
 func (h adminHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	ip, port, err := net.SplitHostPort(r.RemoteAddr)
+	if err != nil {
+		ip = r.RemoteAddr
+		port = ""
+	}
 	log := Log().Named("admin.api").With(
 		zap.String("method", r.Method),
 		zap.String("host", r.Host),
 		zap.String("uri", r.RequestURI),
-		zap.String("remote_addr", r.RemoteAddr),
+		zap.String("remote_ip", ip),
+		zap.String("remote_port", port),
 		zap.Reflect("headers", r.Header),
 	)
 	if r.TLS != nil {

caddyconfig/httpcaddyfile/builtins_test.go

@@ -37,7 +37,7 @@ func TestLogDirectiveSyntax(t *testing.T) {
 					format filter {
 						wrap console
 						fields {
-							request>remote_addr ip_mask {
+							request>remote_ip ip_mask {
 								ipv4 24
 								ipv6 32
 							}
@@ -46,7 +46,7 @@ func TestLogDirectiveSyntax(t *testing.T) {
 				}
 			}
 			`,
-			output:      `{"logging":{"logs":{"default":{"exclude":["http.log.access.log0"]},"log0":{"encoder":{"fields":{"request\u003eremote_addr":{"filter":"ip_mask","ipv4_cidr":24,"ipv6_cidr":32}},"format":"filter","wrap":{"format":"console"}},"include":["http.log.access.log0"]}}},"apps":{"http":{"servers":{"srv0":{"listen":[":8080"],"logs":{"default_logger_name":"log0"}}}}}}`,
+			output:      `{"logging":{"logs":{"default":{"exclude":["http.log.access.log0"]},"log0":{"encoder":{"fields":{"request\u003eremote_ip":{"filter":"ip_mask","ipv4_cidr":24,"ipv6_cidr":32}},"format":"filter","wrap":{"format":"console"}},"include":["http.log.access.log0"]}}},"apps":{"http":{"servers":{"srv0":{"listen":[":8080"],"logs":{"default_logger_name":"log0"}}}}}}`,
 			expectError: false,
 		},
 		{

caddytest/integration/caddyfile_adapt/global_options_log_custom.txt

@@ -3,7 +3,7 @@
 		format filter {
 			wrap console
 			fields {
-				request>remote_addr ip_mask {
+				request>remote_ip ip_mask {
 					ipv4 24
 					ipv6 32
 				}
@@ -18,7 +18,7 @@
 			"custom-logger": {
 				"encoder": {
 					"fields": {
-						"request\u003eremote_addr": {
+						"request\u003eremote_ip": {
 							"filter": "ip_mask",
 							"ipv4_cidr": 24,
 							"ipv6_cidr": 32

caddytest/integration/caddyfile_adapt/log_filters.txt

@@ -15,7 +15,7 @@ log {
 				replace foo REDACTED
 				delete bar
 			}
-			request>remote_addr ip_mask {
+			request>remote_ip ip_mask {
 				ipv4 24
 				ipv6 32
 			}
@@ -64,7 +64,7 @@ log {
 						"request\u003eheaders\u003eServer": {
 							"filter": "delete"
 						},
-						"request\u003eremote_addr": {
+						"request\u003eremote_ip": {
 							"filter": "ip_mask",
 							"ipv4_cidr": 24,
 							"ipv6_cidr": 32

modules/caddyhttp/marshalers.go

@@ -16,6 +16,7 @@ package caddyhttp
 
 import (
 	"crypto/tls"
+	"net"
 	"net/http"
 	"strings"
 
@@ -27,7 +28,14 @@ type LoggableHTTPRequest struct{ *http.Request }
 
 // MarshalLogObject satisfies the zapcore.ObjectMarshaler interface.
 func (r LoggableHTTPRequest) MarshalLogObject(enc zapcore.ObjectEncoder) error {
-	enc.AddString("remote_addr", r.RemoteAddr)
+	ip, port, err := net.SplitHostPort(r.RemoteAddr)
+	if err != nil {
+		ip = r.RemoteAddr
+		port = ""
+	}
+
+	enc.AddString("remote_ip", ip)
+	enc.AddString("remote_port", port)
 	enc.AddString("proto", r.Proto)
 	enc.AddString("method", r.Method)
 	enc.AddString("host", r.Host)