add basic command framework and apiserver

pkg/api/client/transport/transport.go

@@ -0,0 +1,57 @@
+// Package transport provides function to send request to remote endpoints.
+package transport
+
+import (
+	"fmt"
+	"net/http"
+
+	"github.com/docker/go-connections/sockets"
+)
+
+// apiTransport holds information about the http transport to connect with the API.
+type apiTransport struct {
+	*http.Client
+	*tlsInfo
+	transport *http.Transport
+}
+
+// NewTransportWithHTTP creates a new transport based on the provided proto, address and http client.
+// It uses Docker's default http transport configuration if the client is nil.
+// It does not modify the client's transport if it's not nil.
+func NewTransportWithHTTP(proto, addr string, client *http.Client) (Client, error) {
+	var transport *http.Transport
+
+	if client != nil {
+		tr, ok := client.Transport.(*http.Transport)
+		if !ok {
+			return nil, fmt.Errorf("unable to verify TLS configuration, invalid transport %v", client.Transport)
+		}
+		transport = tr
+	} else {
+		transport = defaultTransport(proto, addr)
+		client = &http.Client{
+			Transport: transport,
+		}
+	}
+
+	return &apiTransport{
+		Client:    client,
+		tlsInfo:   &tlsInfo{transport.TLSClientConfig},
+		transport: transport,
+	}, nil
+}
+
+// CancelRequest stops a request execution.
+func (a *apiTransport) CancelRequest(req *http.Request) {
+	a.transport.CancelRequest(req)
+}
+
+// defaultTransport creates a new http.Transport with Docker's
+// default transport configuration.
+func defaultTransport(proto, addr string) *http.Transport {
+	tr := new(http.Transport)
+	sockets.ConfigureTransport(tr, proto, addr)
+	return tr
+}
+
+var _ Client = &apiTransport{}