feat(pkg/cmd): new root command

It setups sub-commands and initialize the abstract factory injecting it
within them.

pkg/cmd/trace.go

@@ -0,0 +1,84 @@
+package cmd
+
+import (
+	"fmt"
+
+	"github.com/fntlnz/kubectl-trace/factory"
+
+	"github.com/spf13/cobra"
+	"k8s.io/cli-runtime/pkg/genericclioptions"
+	// cmdutil "k8s.io/kubernetes/pkg/kubectl/cmd/util"
+	// "k8s.io/kubernetes/pkg/kubectl/util/i18n"
+	// "k8s.io/kubectl/pkg/pluginutils"
+)
+
+// Possible resources include (case insensitive):
+//   pod (po), node
+
+var (
+	traceLong = `Configure, execute, and manage bpftrace programs.
+
+These commands help you trace existing application resources.
+	`
+	traceExamples = `
+  # Execute a bpftrace program from file on a specific node
+  %[1]s trace run kubernetes-node-emt8.c.myproject.internal -p read.bt
+
+  # Get all bpftrace programs in all namespaces
+  %[1]s trace get --all-namespaces
+
+  # Delete all bpftrace programs in a specific namespace
+  %[1]s trace delete -n myns
+`
+)
+
+// TraceOptions ...
+type TraceOptions struct {
+	configFlags *genericclioptions.ConfigFlags
+
+	genericclioptions.IOStreams
+}
+
+// NewTraceOptions provides an instance of TraceOptions with default values.
+func NewTraceOptions(streams genericclioptions.IOStreams) *TraceOptions {
+	return &TraceOptions{
+		configFlags: genericclioptions.NewConfigFlags(),
+
+		IOStreams: streams,
+	}
+}
+
+// NewTraceCommand creates the trace command and its nested children.
+func NewTraceCommand(streams genericclioptions.IOStreams) *cobra.Command {
+	o := NewTraceOptions(streams)
+
+	cmd := &cobra.Command{
+		Use:                   "trace",
+		DisableFlagsInUseLine: true,
+		Short:                 `Execute and manage bpftrace programs`, // Wrap with i18n.T()
+		Long:                  traceLong,                              // Wrap with templates.LongDesc()
+		Example:               fmt.Sprintf(traceExamples, "kubectl"),  // Wrap with templates.Examples()
+		Run: func(c *cobra.Command, args []string) {
+			c.SetOutput(streams.ErrOut)
+			cobra.NoArgs(c, args)
+			c.Help()
+		},
+	}
+
+	flags := cmd.PersistentFlags()
+	o.configFlags.AddFlags(flags)
+
+	matchVersionFlags := factory.NewMatchVersionFlags(o.configFlags)
+	matchVersionFlags.AddFlags(flags)
+
+	// flags.AddGoFlagSet(flag.CommandLine) // todo(leodido) > evaluate whether we need this or not
+
+	f := factory.NewFactory(matchVersionFlags)
+
+	cmd.AddCommand(NewRunCommand(f, streams))
+	cmd.AddCommand(NewGetCommand(f, streams))
+	cmd.AddCommand(NewAttachCommand(streams))
+	cmd.AddCommand(NewDeleteCommand(streams))
+
+	return cmd
+}