Switch to spf13/cobra from urfave/cli

There's A LOT happening in this commit, so here's an outline:

First off, urfave/cli has been removed in favour of spf13/cobra. With
this, comes changes to the formatting as well as the help page for
Kompose.

Upon converting, I noticed a CLI flag was NOT appearing for OpenShift.
Specifically, --deploymentconfig. This has been added with a note
that says it is OpenShift only.

Exit codes have been fixed. If the conversion / down / up fails for
any reason, Kompose will exit with Code 1.

--verbose as well as --suppress-warnings can now be set at the
same time.

app_test.go in the cli directory has been moved to pkg/transformer
to better reflect the testing coverage.

version.go has been removed and converted to it's own CLI command in
conjuction with (most) Go software. A new CLI command has been
created. kompose version

--dab isn't a conventional way for short-form CLI paramters. This
has been shortened to -b for bundle.

CLI flags consisting of only two/three letters have been removed due to
it being unconventional for CLI. For example, --dc was removed in preference
for --deploymentconfig

--replicas has been added as an option when using kompose down or
kompose up. This has been added as previously in app.go the
replica amount was hard-coded as 1.

Differentiating names have been used for flags. For example,
persistent flags use the name Global (ex. GlobalOut). Command-specific
flags have their own names (ex. UpOpt).

Closes #239 #253

cmd/root.go

@@ -0,0 +1,92 @@
+/*
+Copyright 2016 The Kubernetes Authors All rights reserved.
+
+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 cmd
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/Sirupsen/logrus"
+	"github.com/spf13/cobra"
+)
+
+// Logrus hooks
+
+// Hook for erroring and exit out on warning
+type errorOnWarningHook struct{}
+
+func (errorOnWarningHook) Levels() []logrus.Level {
+	return []logrus.Level{logrus.WarnLevel}
+}
+
+func (errorOnWarningHook) Fire(entry *logrus.Entry) error {
+	logrus.Fatalln(entry.Message)
+	return nil
+}
+
+var (
+	GlobalBundle, GlobalFile, GlobalProvider                    string
+	GlobalVerbose, GlobalSuppressWarnings, GlobalErrorOnWarning bool
+)
+
+var RootCmd = &cobra.Command{
+	Use:   "kompose",
+	Short: "A tool helping Docker Compose users move to Kubernetes",
+	Long:  `Kompose is a tool to help users who are familiar with docker-compose move to Kubernetes.`,
+	// PersitentPreRun will be "inherited" by all children and ran before *every* command unless
+	// the child has overridden the functionality. This functionality was implemented to check / modify
+	// all global flag calls regardless of app call.
+	PersistentPreRun: func(cmd *cobra.Command, args []string) {
+
+		// Add extra logging when verbosity is passed
+		if GlobalVerbose {
+			logrus.SetLevel(logrus.DebugLevel)
+		}
+
+		// Set the appropriate suppress warnings and error on warning flags
+		if GlobalSuppressWarnings {
+			logrus.SetLevel(logrus.ErrorLevel)
+		} else if GlobalErrorOnWarning {
+			hook := errorOnWarningHook{}
+			logrus.AddHook(hook)
+		}
+
+		// Error out of the user has not chosen Kubernetes or OpenShift
+		provider := strings.ToLower(GlobalProvider)
+		if provider != "kubernetes" && provider != "openshift" {
+			logrus.Fatalf("%s is an unsupported provider. Supported providers are: 'kubernetes', 'openshift'.", GlobalProvider)
+		}
+
+	},
+}
+
+func Execute() {
+	if err := RootCmd.Execute(); err != nil {
+		fmt.Println(err)
+		os.Exit(-1)
+	}
+}
+
+func init() {
+	RootCmd.PersistentFlags().BoolVarP(&GlobalVerbose, "verbose", "v", false, "verbose output")
+	RootCmd.PersistentFlags().BoolVar(&GlobalSuppressWarnings, "suppress-warnings", false, "Suppress all warnings")
+	RootCmd.PersistentFlags().BoolVar(&GlobalErrorOnWarning, "error-on-warning", false, "Treat any warning as an error")
+	RootCmd.PersistentFlags().StringVarP(&GlobalFile, "file", "f", "docker-compose.yml", "Specify an alternative compose file")
+	RootCmd.PersistentFlags().StringVarP(&GlobalBundle, "bundle", "b", "", "Specify a Distributed Application GlobalBundle (DAB) file")
+	RootCmd.PersistentFlags().StringVar(&GlobalProvider, "provider", "kubernetes", "Specify a provider. Kubernetes or OpenShift.")
+}