Add command riff doctor

Author: zhitongLIU

docs/riff.md

@@ -20,6 +20,7 @@ riff is for functions
 * [riff application](riff_application.md)	 - applications built from source using application buildpacks
 * [riff completion](riff_completion.md)	 - generate shell completion script
 * [riff credential](riff_credential.md)	 - credentials for container registries
+* [riff doctor](riff_doctor.md)	 - check riff's requirements are installed
 * [riff function](riff_function.md)	 - functions built from source using function buildpacks
 * [riff handler](riff_handler.md)	 - handlers map HTTP requests to applications, functions or images
 * [riff processor](riff_processor.md)	 - processors apply functions to messages on streams

docs/riff_doctor.md

@@ -0,0 +1,36 @@
+## riff doctor
+
+check riff's requirements are installed
+
+### Synopsis
+
+<todo>
+
+```
+riff doctor [flags]
+```
+
+### Examples
+
+```
+riff doctor
+```
+
+### Options
+
+```
+  -h, --help   help for doctor
+```
+
+### Options inherited from parent commands
+
+```
+      --config file        config file (default is $HOME/.riff.yaml)
+      --kube-config file   kubectl config file (default is $HOME/.kube/config)
+      --no-color           disable color output in terminals
+```
+
+### SEE ALSO
+
+* [riff](riff.md)	 - riff is for functions
+

pkg/riff/commands/riff.go

@@ -39,6 +39,7 @@ func NewRiffCommand(c *cli.Config) *cobra.Command {
 	cmd.AddCommand(NewHandlerCommand(c))
 	cmd.AddCommand(NewStreamCommand(c))
 	cmd.AddCommand(NewProcessorCommand(c))
+	cmd.AddCommand(NewDoctorCommand(c))
 
 	return cmd
 }

pkg/riff/commands/riff_test.go

@@ -17,6 +17,7 @@
 package commands_test
 
 import (
+	"github.com/projectriff/riff/pkg/cli"
 	"testing"
 
 	"github.com/projectriff/riff/pkg/riff/commands"
@@ -33,3 +34,14 @@ func TestRiffCommand(t *testing.T) {
 
 	table.Run(t, commands.NewRiffCommand)
 }
+
+func TestRiffMainSubCommands(t *testing.T) {
+	riffCommand := commands.NewRiffCommand(cli.NewDefaultConfig())
+	commands := riffCommand.Commands()
+
+	expectedCount := 7
+	count := len(commands)
+	if count != expectedCount {
+		t.Fatalf("Expected %d riff subcommands, got %d", expectedCount, count)
+	}
+}