internal/log: Implement logging of HOST when using subrequest auth (#1027)

* internal/log: Implement logging of HOST when using subrequest auth

The host header wouldn't be set on subrequest auth, so we need to look for X-Forwarded-Host header when logging requests.

* chore: add changelog entry

---------

Signed-off-by: Xe Iaso <xe.iaso@techaro.lol>
Co-authored-by: Xe Iaso <xe.iaso@techaro.lol>

internal/log_test.go

@@ -3,6 +3,8 @@ package internal
 import (
 	"bytes"
 	"log"
+	"log/slog"
+	"net/http"
 	"strings"
 	"testing"
 )
@@ -44,3 +46,37 @@ func TestErrorLogFilter(t *testing.T) {
 	}
 	buf.Reset()
 }
+
+func TestGetRequestLogger(t *testing.T) {
+	// Test case 1: Normal request with Host header
+	req1, _ := http.NewRequest("GET", "http://example.com/test", nil)
+	req1.Host = "example.com"
+
+	logger := slog.Default()
+	reqLogger := GetRequestLogger(logger, req1)
+
+	// We can't easily test the actual log output without setting up a test handler,
+	// but we can verify the function doesn't panic and returns a logger
+	if reqLogger == nil {
+		t.Error("GetRequestLogger returned nil")
+	}
+
+	// Test case 2: Subrequest auth mode with X-Forwarded-Host
+	req2, _ := http.NewRequest("GET", "http://test.com/auth", nil)
+	req2.Host = ""
+	req2.Header.Set("X-Forwarded-Host", "original-site.com")
+
+	reqLogger2 := GetRequestLogger(logger, req2)
+	if reqLogger2 == nil {
+		t.Error("GetRequestLogger returned nil for X-Forwarded-Host case")
+	}
+
+	// Test case 3: No host information available
+	req3, _ := http.NewRequest("GET", "http://test.com/nohost", nil)
+	req3.Host = ""
+
+	reqLogger3 := GetRequestLogger(logger, req3)
+	if reqLogger3 == nil {
+		t.Error("GetRequestLogger returned nil for no host case")
+	}
+}