add 'ilm show -t' to show a better visualization of a ilm policy (#57)

cmd/ilm.go

@@ -103,6 +103,15 @@ func IlmShow(conf *cfg.Config) *cli.Command {
 		Usage:     "show details about an index lifecycle policy",
 		UsageText: "show <policy>",
 
+		Flags: []cli.Flag{
+			&cli.BoolFlag{
+				Name:        "tree",
+				Usage:       "display policy as a tree",
+				Destination: &conf.Ilm.Tree,
+				Aliases:     []string{"t"},
+			},
+		},
+
 		Action: func(ctx context.Context, cmd *cli.Command) error {
 			policy := cmd.Args().Get(0)
 			if policy == "" {

pkg/cfg/ilm.go

@@ -42,6 +42,7 @@ type Ilm struct {
 	DeleteSearchableSnapshots bool
 
 	MinAge, FromPhase, Within string // forecast
+	Tree                      bool
 }
 
 func (cfg *Ilm) HaveHot() bool {

pkg/es/ilm.go

@@ -121,6 +121,10 @@ func IlmShow(conf *cfg.Config, policy string) error {
 		return errors.New("no ilm policy retrieved")
 	}
 
+	if conf.Ilm.Tree {
+		return IlmShowTree(conf, ilm.Policy)
+	}
+
 	table := printer.NewTable(conf, 2, 5)
 	table.Addheaders("ilm policy setting", "value")
 
@@ -135,6 +139,69 @@ func IlmShow(conf *cfg.Config, policy string) error {
 	return table.Print()
 }
 
+// Visualize  phases or  a ILM  policy, taking  into account  that the
+// minAge for the current phases is set in the next phase
+func IlmShowTree(conf *cfg.Config, ilm types.IlmPolicy) error {
+	indent := ""
+
+	table := printer.NewTable(conf, 4, 0)
+	table.Addheaders("phase", "min age", "min size", "snapshot repo")
+
+	for _, phase := range IlmPhaseOrder {
+		if phase == "hot" {
+			fmt.Printf("%s%s phase:\n%s      rollover after %s\n%s      or rollover when storage > %s\n",
+				indent, phase,
+				indent, formatDuration(parseDuration(ilm.Phases.Hot.Actions.Rollover.MaxAge.(string))),
+				indent, ilm.Phases.Hot.Actions.Rollover.MaxPrimaryShardSize,
+			)
+
+			indent += "    "
+			continue
+		}
+
+		current := getIlmCurrentPhase(ilm, phase)
+
+		if current == nil {
+			continue
+		}
+
+		next := findNextPhase(ilm, phase)
+
+		fmt.Printf("%s%s phase:\n", indent, phase)
+
+		if next != nil {
+			fmt.Printf("%s      rollover after %s\n",
+				indent, formatDuration(next.minage),
+			)
+
+			if current.Actions.SearchableSnapshot != nil {
+				fmt.Printf("%s      snapshot repo: %s\n",
+					indent, current.Actions.SearchableSnapshot.SnapshotRepository,
+				)
+			}
+		}
+
+		indent += "    "
+	}
+
+	return nil
+}
+
+func getIlmCurrentPhase(policy types.IlmPolicy, currentPhase string) *types.Phase {
+	switch currentPhase {
+	case "hot":
+		return policy.Phases.Hot
+	case "warm":
+		return policy.Phases.Warm
+	case "cold":
+		return policy.Phases.Cold
+	case "frozen":
+		return policy.Phases.Frozen
+	default:
+		return policy.Phases.Delete
+	}
+}
+
 func ilmPhaseString(phase *types.Phase, short bool) string {
 	if phase == nil {
 		return ""