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/proxy.go

@@ -0,0 +1,165 @@
+//
+// 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"
+	"path/filepath"
+
+	"github.com/mitchellh/mapstructure"
+	"github.com/sirupsen/logrus"
+)
+
+// ProxyConfig is a structure storing information needed from any
+// proxy in order to be properly initialized.
+type ProxyConfig struct {
+	Path  string
+	Debug bool
+}
+
+// proxyParams is the structure providing specific parameters needed
+// for the execution of the proxy binary.
+type proxyParams struct {
+	agentURL string
+}
+
+// ProxyType describes a proxy type.
+type ProxyType string
+
+const (
+	// NoopProxyType is the noopProxy.
+	NoopProxyType ProxyType = "noopProxy"
+
+	// NoProxyType is the noProxy.
+	NoProxyType ProxyType = "noProxy"
+
+	// CCProxyType is the ccProxy.
+	CCProxyType ProxyType = "ccProxy"
+
+	// KataProxyType is the kataProxy.
+	KataProxyType ProxyType = "kataProxy"
+)
+
+const (
+	// Number of seconds to wait for the proxy to respond to a connection
+	// request.
+	waitForProxyTimeoutSecs = 5.0
+)
+
+func proxyLogger() *logrus.Entry {
+	return virtLog.WithField("subsystem", "proxy")
+}
+
+// Set sets a proxy type based on the input string.
+func (pType *ProxyType) Set(value string) error {
+	switch value {
+	case "noopProxy":
+		*pType = NoopProxyType
+		return nil
+	case "noProxy":
+		*pType = NoProxyType
+		return nil
+	case "ccProxy":
+		*pType = CCProxyType
+		return nil
+	case "kataProxy":
+		*pType = KataProxyType
+		return nil
+	default:
+		return fmt.Errorf("Unknown proxy type %s", value)
+	}
+}
+
+// String converts a proxy type to a string.
+func (pType *ProxyType) String() string {
+	switch *pType {
+	case NoopProxyType:
+		return string(NoopProxyType)
+	case NoProxyType:
+		return string(NoProxyType)
+	case CCProxyType:
+		return string(CCProxyType)
+	case KataProxyType:
+		return string(KataProxyType)
+	default:
+		return ""
+	}
+}
+
+// newProxy returns a proxy from a proxy type.
+func newProxy(pType ProxyType) (proxy, error) {
+	switch pType {
+	case NoopProxyType:
+		return &noopProxy{}, nil
+	case NoProxyType:
+		return &noProxy{}, nil
+	case CCProxyType:
+		return &ccProxy{}, nil
+	case KataProxyType:
+		return &kataProxy{}, nil
+	default:
+		return &noopProxy{}, nil
+	}
+}
+
+// newProxyConfig returns a proxy config from a generic PodConfig handler,
+// after it properly checked the configuration was valid.
+func newProxyConfig(podConfig *PodConfig) (ProxyConfig, error) {
+	if podConfig == nil {
+		return ProxyConfig{}, fmt.Errorf("Pod config cannot be nil")
+	}
+
+	var config ProxyConfig
+	switch podConfig.ProxyType {
+	case KataProxyType:
+		fallthrough
+	case CCProxyType:
+		if err := mapstructure.Decode(podConfig.ProxyConfig, &config); err != nil {
+			return ProxyConfig{}, err
+		}
+	}
+
+	if config.Path == "" {
+		return ProxyConfig{}, fmt.Errorf("Proxy path cannot be empty")
+	}
+
+	return config, nil
+}
+
+func defaultProxyURL(pod Pod, socketType string) (string, error) {
+	switch socketType {
+	case SocketTypeUNIX:
+		socketPath := filepath.Join(runStoragePath, pod.id, "proxy.sock")
+		return fmt.Sprintf("unix://%s", socketPath), nil
+	case SocketTypeVSOCK:
+		// TODO Build the VSOCK default URL
+		return "", nil
+	default:
+		return "", fmt.Errorf("Unknown socket type: %s", socketType)
+	}
+}
+
+// proxy is the virtcontainers proxy interface.
+type proxy interface {
+	// start launches a proxy instance for the specified pod, returning
+	// the PID of the process and the URL used to connect to it.
+	start(pod Pod, params proxyParams) (int, string, error)
+
+	// stop terminates a proxy instance after all communications with the
+	// agent inside the VM have been properly stopped.
+	stop(pod Pod, pid int) error
+}