Use Docker Desktop proxy when Desktop is running

Signed-off-by: Guillaume Tardif <guillaume.tardif@gmail.com>

Author: gtardif

pkg/desktop/paths.go

@@ -4,6 +4,7 @@ import "sync"
 
 type DockerDesktopPaths struct {
 	BackendSocket string
+	ProxySocket   string
 }
 
 var Paths = sync.OnceValue(func() DockerDesktopPaths {

pkg/desktop/socket/dial.go

@@ -0,0 +1,9 @@
+package socket
+
+import (
+	"strings"
+)
+
+func stripUnixScheme(path string) string {
+	return strings.TrimPrefix(path, "unix://")
+}

pkg/desktop/socket/dial_unix.go

@@ -0,0 +1,12 @@
+//go:build !windows
+
+package socket
+
+import (
+	"net"
+)
+
+// DialUnix is a simple wrapper for `net.Dial("unix")`.
+func DialUnix(path string) (net.Conn, error) {
+	return net.DialUnix("unix", nil, &net.UnixAddr{Name: stripUnixScheme(path), Net: "unix"})
+}

pkg/desktop/socket/dial_windows.go

@@ -0,0 +1,24 @@
+package socket
+
+import (
+	"context"
+	"net"
+	"strings"
+	"time"
+
+	"github.com/Microsoft/go-winio"
+)
+
+// DialUnix is a simple wrapper for `winio.DialPipe(path, 10s)`.
+// It provides API compatibility for named pipes with the Unix domain socket API.
+func DialUnix(path string) (net.Conn, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+
+	if strings.HasPrefix(path, "unix://") {
+		// windows supports AF_UNIX
+		d := &net.Dialer{}
+		return d.DialContext(ctx, "unix", stripUnixScheme(path))
+	}
+	return winio.DialPipeContext(ctx, path)
+}

pkg/desktop/sockets_darwin.go

@@ -15,5 +15,6 @@ func getDockerDesktopPaths() (DockerDesktopPaths, error) {
 
 	return DockerDesktopPaths{
 		BackendSocket: filepath.Join(data, "backend.sock"),
+		ProxySocket:   filepath.Join(data, "httpproxy.sock"),
 	}, nil
 }

pkg/desktop/sockets_linux.go

@@ -12,6 +12,7 @@ func getDockerDesktopPaths() (DockerDesktopPaths, error) {
 		// Inside LinuxKit
 		return DockerDesktopPaths{
 			BackendSocket: "/run/host-services/backend.sock",
+			ProxySocket:   "/run/host-services/httpproxy.sock",
 		}, nil
 	}
 

pkg/desktop/sockets_windows.go

@@ -13,5 +13,6 @@ func getDockerDesktopPaths() (DockerDesktopPaths, error) {
 
 	return DockerDesktopPaths{
 		BackendSocket: `\\.\pipe\dockerBackendApiServer`,
+		ProxySocket:   `\\.\pipe\dockerHTTPProxy`,
 	}, nil
 }

pkg/httpclient/client.go

@@ -1,12 +1,16 @@
 package httpclient
 
 import (
+	"context"
 	"fmt"
 	"maps"
+	"net"
 	"net/http"
 	"net/url"
 	"runtime"
 
+	"github.com/docker/docker-agent/pkg/desktop"
+	socket "github.com/docker/docker-agent/pkg/desktop/socket"
 	"github.com/docker/docker-agent/pkg/version"
 )
 
@@ -95,13 +99,25 @@ func WithQuery(query url.Values) Opt {
 	}
 }
 
-// newTransport returns an HTTP transport with automatic gzip compression disabled.
+// newTransport returns an HTTP transport with automatic gzip compression disabled and using Docker Desktop proxy if available.
 func newTransport() http.RoundTripper {
 	t, ok := http.DefaultTransport.(*http.Transport)
 	if !ok {
 		return http.DefaultTransport
 	}
 	transport := t.Clone()
+
+	if desktop.IsDockerDesktopRunning(context.Background()) {
+		// Route all traffic through Docker Desktop's HTTP proxy socket
+		// Set a dummy proxy URL - the actual connection happens via DialContext
+		transport.Proxy = http.ProxyURL(&url.URL{
+			Scheme: "http",
+		})
+		// Override the dialer to connect to the Unix socket for the proxy
+		transport.DialContext = func(ctx context.Context, network, addr string) (net.Conn, error) {
+			return socket.DialUnix(desktop.Paths().ProxySocket)
+		}
+	}
 	transport.DisableCompression = true
 	return transport
 }