add basic command framework and apiserver

pkg/api/client/client.go

@@ -0,0 +1,106 @@
+package client
+
+import (
+	"fmt"
+	"net/http"
+	"net/url"
+	"strings"
+
+	"github.com/gostor/gotgt/pkg/api/client/transport"
+)
+
+type Client struct {
+	// proto holds the client protocol i.e. unix.
+	proto string
+	// addr holds the client address.
+	addr string
+	// basePath holds the path to prepend to the requests.
+	basePath string
+	// transport is the interface to send request with, it implements transport.Client.
+	transport transport.Client
+	// version of the server to talk to.
+	version string
+	// custom http headers configured by users.
+	customHTTPHeaders map[string]string
+}
+
+// NewClient initializes a new API client for the given host and API version.
+// It uses the given http client as transport.
+// It also initializes the custom http headers to add to each request.
+//
+// It won't send any version information if the version number is empty. It is
+// highly recommended that you set a version or your client may break if the
+// server is upgraded.
+func NewClient(host string, version string, client *http.Client, httpHeaders map[string]string) (*Client, error) {
+	proto, addr, basePath, err := ParseHost(host)
+	if err != nil {
+		return nil, err
+	}
+
+	transport, err := transport.NewTransportWithHTTP(proto, addr, client)
+	if err != nil {
+		return nil, err
+	}
+
+	return &Client{
+		proto:             proto,
+		addr:              addr,
+		basePath:          basePath,
+		transport:         transport,
+		version:           version,
+		customHTTPHeaders: httpHeaders,
+	}, nil
+}
+
+// getAPIPath returns the versioned request path to call the api.
+// It appends the query parameters to the path if they are not empty.
+func (cli *Client) getAPIPath(p string, query url.Values) string {
+	var apiPath string
+	if cli.version != "" {
+		v := strings.TrimPrefix(cli.version, "v")
+		apiPath = fmt.Sprintf("%s/v%s%s", cli.basePath, v, p)
+	} else {
+		apiPath = fmt.Sprintf("%s%s", cli.basePath, p)
+	}
+
+	u := &url.URL{
+		Path: apiPath,
+	}
+	if len(query) > 0 {
+		u.RawQuery = query.Encode()
+	}
+	return u.String()
+}
+
+// ClientVersion returns the version string associated with this
+// instance of the Client. Note that this value can be changed
+// via the DOCKER_API_VERSION env var.
+func (cli *Client) ClientVersion() string {
+	return cli.version
+}
+
+// UpdateClientVersion updates the version string associated with this
+// instance of the Client.
+func (cli *Client) UpdateClientVersion(v string) {
+	cli.version = v
+}
+
+// ParseHost verifies that the given host strings is valid.
+func ParseHost(host string) (string, string, string, error) {
+	protoAddrParts := strings.SplitN(host, "://", 2)
+	if len(protoAddrParts) == 1 {
+		return "", "", "", fmt.Errorf("unable to parse docker host `%s`", host)
+	}
+
+	var basePath string
+	proto, addr := protoAddrParts[0], protoAddrParts[1]
+	if proto == "tcp" {
+		parsed, err := url.Parse("tcp://" + addr)
+		if err != nil {
+			return "", "", "", err
+		}
+		addr = parsed.Host
+		basePath = parsed.Path
+	}
+	return proto, addr, basePath, nil
+}