virtcontainers: Initial import

This is a virtcontainers 1.0.8 import into Kata Containers runtime.

virtcontainers is a Go library designed to manage hardware virtualized
pods and containers. It is the core Clear Containers framework and will
become the core Kata Containers framework, as discussed at
https://github.com/kata-containers/runtime/issues/33

Some more more pointers:

virtcontainers README, including some design and architecure notes:
https://github.com/containers/virtcontainers/blob/master/README.md

virtcontainers 1.0 API:
https://github.com/containers/virtcontainers/blob/master/documentation/api/1.0/api.md

Fixes #40

Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

virtcontainers/no_proxy.go

@@ -0,0 +1,48 @@
+//
+// Copyright (c) 2017 Intel Corporation
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+
+package virtcontainers
+
+import (
+	"fmt"
+)
+
+// This is the no proxy implementation of the proxy interface. This
+// is a generic implementation for any case (basically any agent),
+// where no actual proxy is needed. This happens when the combination
+// of the VM and the agent can handle multiple connections without
+// additional component to handle the multiplexing. Both the runtime
+// and the shim will connect to the agent through the VM, bypassing
+// the proxy model.
+// That's why this implementation is very generic, and all it does
+// is to provide both shim and runtime the correct URL to connect
+// directly to the VM.
+type noProxy struct {
+}
+
+// start is noProxy start implementation for proxy interface.
+func (p *noProxy) start(pod Pod, params proxyParams) (int, string, error) {
+	if params.agentURL == "" {
+		return -1, "", fmt.Errorf("AgentURL cannot be empty")
+	}
+
+	return 0, params.agentURL, nil
+}
+
+// stop is noProxy stop implementation for proxy interface.
+func (p *noProxy) stop(pod Pod, pid int) error {
+	return nil
+}