cli: Add initial cli implementation.

- Add kata-runtime
- Add unit test
- Add Makefile to build cli

Fixes: #33

Signed-off-by: Julio Montes <julio.montes@intel.com>
Signed-off-by: James O. D. Hunt <james.o.hunt@intel.com>
Signed-off-by: Jose Carlos Venegas Munoz <jose.carlos.venegas.munoz@intel.com>

cli/logger.go

@@ -0,0 +1,79 @@
+// 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 main
+
+import (
+	"log/syslog"
+	"time"
+
+	"github.com/sirupsen/logrus"
+	lSyslog "github.com/sirupsen/logrus/hooks/syslog"
+)
+
+// sysLogHook wraps a syslog logrus hook and a formatter to be used for all
+// syslog entries.
+//
+// This is necessary to allow the main logger (for "--log=") to use a custom
+// formatter ("--log-format=") whilst allowing the system logger to use a
+// different formatter.
+type sysLogHook struct {
+	shook     *lSyslog.SyslogHook
+	formatter logrus.Formatter
+}
+
+func (h *sysLogHook) Levels() []logrus.Level {
+	return h.shook.Levels()
+}
+
+// Fire is responsible for adding a log entry to the system log. It switches
+// formatter before adding the system log entry, then reverts the original log
+// formatter.
+func (h *sysLogHook) Fire(e *logrus.Entry) (err error) {
+	formatter := e.Logger.Formatter
+
+	e.Logger.Formatter = h.formatter
+
+	err = h.shook.Fire(e)
+
+	e.Logger.Formatter = formatter
+
+	return err
+}
+
+func newSystemLogHook(network, raddr string) (*sysLogHook, error) {
+	hook, err := lSyslog.NewSyslogHook(network, raddr, syslog.LOG_INFO, name)
+	if err != nil {
+		return nil, err
+	}
+
+	return &sysLogHook{
+		formatter: &logrus.TextFormatter{
+			TimestampFormat: time.RFC3339Nano,
+		},
+		shook: hook,
+	}, nil
+}
+
+// handleSystemLog sets up the system-level logger.
+func handleSystemLog(network, raddr string) error {
+	hook, err := newSystemLogHook(network, raddr)
+	if err != nil {
+		return err
+	}
+
+	kataLog.Logger.Hooks.Add(hook)
+
+	return nil
+}