Move engine-api client package

This moves the engine-api client package to `/docker/docker/client`.

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

client/plugin_install.go

@@ -0,0 +1,59 @@
+// +build experimental
+
+package client
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/url"
+
+	"github.com/docker/docker/api/types"
+	"golang.org/x/net/context"
+)
+
+// PluginInstall installs a plugin
+func (cli *Client) PluginInstall(ctx context.Context, name string, options types.PluginInstallOptions) error {
+	// FIXME(vdemeester) name is a ref, we might want to parse/validate it here.
+	query := url.Values{}
+	query.Set("name", name)
+	resp, err := cli.tryPluginPull(ctx, query, options.RegistryAuth)
+	if resp.statusCode == http.StatusUnauthorized && options.PrivilegeFunc != nil {
+		newAuthHeader, privilegeErr := options.PrivilegeFunc()
+		if privilegeErr != nil {
+			ensureReaderClosed(resp)
+			return privilegeErr
+		}
+		resp, err = cli.tryPluginPull(ctx, query, newAuthHeader)
+	}
+	if err != nil {
+		ensureReaderClosed(resp)
+		return err
+	}
+	var privileges types.PluginPrivileges
+	if err := json.NewDecoder(resp.body).Decode(&privileges); err != nil {
+		ensureReaderClosed(resp)
+		return err
+	}
+	ensureReaderClosed(resp)
+
+	if !options.AcceptAllPermissions && options.AcceptPermissionsFunc != nil && len(privileges) > 0 {
+		accept, err := options.AcceptPermissionsFunc(privileges)
+		if err != nil {
+			return err
+		}
+		if !accept {
+			resp, _ := cli.delete(ctx, "/plugins/"+name, nil, nil)
+			ensureReaderClosed(resp)
+			return pluginPermissionDenied{name}
+		}
+	}
+	if options.Disabled {
+		return nil
+	}
+	return cli.PluginEnable(ctx, name)
+}
+
+func (cli *Client) tryPluginPull(ctx context.Context, query url.Values, registryAuth string) (serverResponse, error) {
+	headers := map[string][]string{"X-Registry-Auth": {registryAuth}}
+	return cli.post(ctx, "/plugins/pull", query, nil, headers)
+}