cmd: add more details in --help flag

cmd/ignite/cmd/vmcmd/ps.go

@@ -21,6 +21,28 @@ func NewCmdPs(out io.Writer) *cobra.Command {
  Long: dedent.Dedent(`
  List all running VMs. By specifying the all flag (-a, --all),
  also list VMs that are not currently running.
+ Using the -f (--filter) flag, you can give conditions VMs should fullfilled to be displayed.
+ You can filter on all the underlying fields of the VM struct, see the documentation:
+ https://ignite.readthedocs.io/en/stable/api/ignite_v1alpha2.html#VM.
+
+ Different operators can be used:
+ - "=" and "==" for the equal
+ - "!=" for the is not equal
+ - "=~" for the contains
+ - "!~" for the not contains
+
+ Non-exhaustive list of identifiers to apply filter on:
+ - the VM name
+ - CPUs usage
+ - Labels
+ - Image
+ - Kernel
+ - Memory
+
+ Example usage:
+ $ ignite ps -f "{{.ObjectMeta.Name}}=my-vm2,{{.Spec.CPUs}}!=3,{{.Spec.Image.OCI}}=~weaveworks/ignite-ubuntu"
+
+ $ ignite ps -f "{{.Spec.Memory}}=~1024,{{.Status.Running}}=true"
  `),
  Run: func(cmd *cobra.Command, args []string) {
  // If `ps` is called via any of its aliases

cmd/ignite/run/ps.go

@@ -43,7 +43,7 @@ func Ps(po *psOptions) error {
  for _, vm := range po.allVMs {
  isExpectedVM := true
  if filtering {
- isExpectedVM, err = filters.AreExpected(vm.GetObjectMeta())
+ isExpectedVM, err = filters.AreExpected(vm)
  if err != nil {
  return err
  }