--provider global flag for kompose

Now a user can select a provider using global flag
--provider=openshift to select openshift provider
or --provider-kubernetes to select kubernetes provider
if nothing is provided kubernetes is the default provider.

Fixes #179

cli/command/command.go

@@ -18,60 +18,134 @@ package command
 
 import (
 	"fmt"
+	"strings"
 
+	"github.com/Sirupsen/logrus"
 	"github.com/skippbox/kompose/cli/app"
 	"github.com/urfave/cli"
 )
 
-// ConvertCommand defines the kompose convert subcommand.
-func ConvertCommand() cli.Command {
-	return cli.Command{
+// 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
+}
+
+// BeforeApp is an action that is executed before any cli command.
+func BeforeApp(c *cli.Context) error {
+
+	if c.GlobalBool("verbose") {
+		logrus.SetLevel(logrus.DebugLevel)
+	} else if c.GlobalBool("suppress-warnings") {
+		logrus.SetLevel(logrus.ErrorLevel)
+	} else if c.GlobalBool("error-on-warning") {
+		hook := errorOnWarningHook{}
+		logrus.AddHook(hook)
+	}
+
+	// First command added was dummy convert command so removing it
+	c.App.Commands = c.App.Commands[1:]
+	provider := strings.ToLower(c.GlobalString("provider"))
+	switch provider {
+	case "kubernetes":
+		c.App.Commands = append(c.App.Commands, ConvertKubernetesCommand())
+	case "openshift":
+		c.App.Commands = append(c.App.Commands, ConvertOpenShiftCommand())
+	default:
+		logrus.Fatalf("Error: Unknown provider name. Providers supported are - 'kubernetes', 'openshift'.")
+	}
+
+	return nil
+}
+
+// When user tries out `kompose -h`, the convert option should be visible
+// so adding a dummy `convert` command, real convert commands depending on Providers
+// mentioned are added in `BeforeApp` function
+func ConvertCommandDummy() cli.Command {
+	command := cli.Command{
+		Name:  "convert",
+		Usage: fmt.Sprintf("Convert Docker Compose file (e.g. %s) to Kubernetes/OpenShift objects", app.DefaultComposeFile),
+	}
+	return command
+}
+
+// ConvertKubernetesCommand defines the kompose convert subcommand for Kubernetes provider
+func ConvertKubernetesCommand() cli.Command {
+	command := cli.Command{
 		Name:  "convert",
 		Usage: fmt.Sprintf("Convert Docker Compose file (e.g. %s) to Kubernetes objects", app.DefaultComposeFile),
 		Action: func(c *cli.Context) {
 			app.Convert(c)
 		},
 		Flags: []cli.Flag{
-			cli.StringFlag{
-				Name:   "out,o",
-				Usage:  "Specify file name in order to save objects into",
-				EnvVar: "OUTPUT_FILE",
+			cli.BoolFlag{
+				Name:  "chart,c",
+				Usage: "Create a Helm chart for converted objects",
 			},
 			cli.BoolFlag{
 				Name:  "deployment,d",
-				Usage: "Generate a deployment resource file (default on)",
+				Usage: "Generate a Kubernetes deployment object (default on)",
 			},
 			cli.BoolFlag{
 				Name:  "daemonset,ds",
-				Usage: "Generate a daemonset resource file",
-			},
-			cli.BoolFlag{
-				Name:  "deploymentconfig,dc",
-				Usage: "Generate a DeploymentConfig for OpenShift",
+				Usage: "Generate a Kubernetes daemonset object",
 			},
 			cli.BoolFlag{
 				Name:  "replicationcontroller,rc",
-				Usage: "Generate a replication controller resource file",
-			},
-			cli.IntFlag{
-				Name:  "replicas",
-				Value: 1,
-				Usage: "Specify the number of replicas in the generated resource spec (default 1)",
+				Usage: "Generate a Kubernetes replication controller object",
 			},
+		},
+	}
+	command.Flags = append(command.Flags, commonConvertFlags()...)
+	return command
+}
+
+// ConvertOpenShiftCommand defines the kompose convert subcommand for OpenShift provider
+func ConvertOpenShiftCommand() cli.Command {
+	command := cli.Command{
+		Name:  "convert",
+		Usage: fmt.Sprintf("Convert Docker Compose file (e.g. %s) to OpenShift objects", app.DefaultComposeFile),
+		Action: func(c *cli.Context) {
+			app.Convert(c)
+		},
+		Flags: []cli.Flag{
 			cli.BoolFlag{
-				Name:  "chart,c",
-				Usage: "Create a chart deployment",
-			},
-			cli.BoolFlag{
-				Name:  "yaml, y",
-				Usage: "Generate resource file in yaml format",
-			},
-			cli.BoolFlag{
-				Name:  "stdout",
-				Usage: "Print Kubernetes objects to stdout",
+				Name:  "deploymentconfig,dc",
+				Usage: "Generate a OpenShift DeploymentConfig object",
 			},
 		},
 	}
+	command.Flags = append(command.Flags, commonConvertFlags()...)
+	return command
+}
+
+func commonConvertFlags() []cli.Flag {
+	return []cli.Flag{
+		cli.StringFlag{
+			Name:   "out,o",
+			Usage:  "Specify file name in order to save objects into",
+			EnvVar: "OUTPUT_FILE",
+		},
+		cli.IntFlag{
+			Name:  "replicas",
+			Value: 1,
+			Usage: "Specify the number of replicas in the generated resource spec (default 1)",
+		},
+		cli.BoolFlag{
+			Name:  "yaml, y",
+			Usage: "Generate resource file in yaml format",
+		},
+		cli.BoolFlag{
+			Name:  "stdout",
+			Usage: "Print converted objects to stdout",
+		},
+	}
 }
 
 // UpCommand defines the kompose up subcommand.
@@ -126,5 +200,12 @@ func CommonFlags() []cli.Flag {
 			Name:  "error-on-warning",
 			Usage: "Treat any warning as error",
 		},
+		// mention the end provider
+		cli.StringFlag{
+			Name:   "provider",
+			Usage:  "Generate artifacts for this provider",
+			Value:  app.DefaultProvider,
+			EnvVar: "PROVIDER",
+		},
 	}
 }