add explain index allocation

cmd/index.go

@@ -38,6 +38,7 @@ func Index(conf *cfg.Config) *cli.Command {
 			IndexCreate(conf),
 			IndexDelete(conf),
 			IndexClose(conf),
+			IndexAllocation(conf),
 		},
 	}
 }
@@ -75,6 +76,33 @@ func IndexList(conf *cfg.Config) *cli.Command {
 	}
 }
 
+func IndexAllocation(conf *cfg.Config) *cli.Command {
+	return &cli.Command{
+		Name:    "allocation",
+		Aliases: []string{"a"},
+		Usage:   "explain index allocation",
+
+		Flags: []cli.Flag{
+			&cli.IntFlag{
+				Name:        "shard",
+				Usage:       "shard number to explain for",
+				Destination: &conf.Shards,
+				Aliases:     []string{"s"},
+			},
+			&cli.BoolFlag{
+				Name:        "primary",
+				Usage:       "explain primary allocation (default true)",
+				Destination: &conf.Primary,
+				Aliases:     []string{"p"},
+			},
+		},
+
+		Action: func(ctx context.Context, cmd *cli.Command) error {
+			return es.IndexAllocation(conf, cmd.Args().Get(0))
+		},
+	}
+}
+
 func IndexShow(conf *cfg.Config) *cli.Command {
 	return &cli.Command{
 		Name:    "show",

pkg/cfg/config.go

@@ -47,8 +47,9 @@ type Config struct {
 	DefaultCluster                 *Cluster
 	Index                          string   // index: -i
 	Failed, Partials               bool     // index: flags
-	Shards, Replicas               int      // index create: -s -r
+	Shards, Replicas               int      // index create+allocation: -s -r
 	Wait                           bool     // index create: -w
+	Primary                        bool     // index allocation: -p
 	From, To, MaxItems             int      // search: flags
 	Filter                         []string // search: -F
 	Exclude                        string   // cluster compare: -e (regexp)

pkg/es/ccr.go

@@ -116,7 +116,7 @@ func CcrRemoteInfo(conf *cfg.Config, index string) error {
 	}
 
 	table := NewTable(2, 5)
-	table.Addheaders("field", "value")
+	table.Addheaders("ccr remote property", "value")
 
 	table.entries = [][]string{
 		{"Remote Cluster", remote},

pkg/es/ccr_follower.go

@@ -176,7 +176,7 @@ func CcrFollowerShow(conf *cfg.Config, index string) error {
 	follower := res.Indices[0].Shards[0]
 
 	table := NewTable(2, 9)
-	table.Addheaders("field", "value")
+	table.Addheaders("ccr follower property", "value")
 
 	table.entries = [][]string{
 		{"name", index},

pkg/es/index.go

@@ -111,7 +111,7 @@ func IndexShow(conf *cfg.Config, index string) error {
 	slog.Debug("ES result", "index", res)
 
 	table := NewTable(2, 5)
-	table.Addheaders("field", "value")
+	table.Addheaders("index property", "value")
 
 	ts, err := strconv.ParseInt(res[index].Settings.Index.CreationDate.(string), 10, 64)
 	if err != nil {
@@ -216,3 +216,52 @@ func IndexClose(conf *cfg.Config, index string) error {
 
 	return nil
 }
+
+func IndexAllocation(conf *cfg.Config, index string) error {
+	if index == "" {
+		return fmt.Errorf("no index specified")
+	}
+
+	alloc := conf.DefaultCluster.ES.Cluster.AllocationExplain().
+		Index(index).
+		Primary(conf.Primary).
+		Shard(conf.Shards)
+
+	res, err := alloc.Header("content-type", "application/json").
+		Header("accept", "application/json").
+		Do(context.Background())
+	if err != nil {
+		return fmt.Errorf("failed to get index allocation explain: %s", err)
+	}
+
+	slog.Debug("ES result", "index", res)
+
+	currentNode := res.CurrentNode
+
+	table := NewTable(2, 10)
+	table.Addheaders("index allocation setting", "value")
+
+	roles := make([]string, len(currentNode.Roles))
+	for idx, role := range currentNode.Roles {
+		roles[idx] = role.Name
+	}
+
+	table.entries = [][]string{
+		{"Index", index},
+		{"Current node", currentNode.Name},
+		{"Current k8s node", currentNode.Attributes["k8s_node_name"]},
+		{"Current node address", currentNode.TransportAddress},
+		{"Current node id", currentNode.Id},
+		{"Current node weight", fmt.Sprintf("%d", currentNode.WeightRanking)},
+		{"Current node roles", strings.Join(roles, ",")},
+		{"Can rebalance cluster", res.CanRebalanceCluster.Name},
+		{"Can rebalance to another node", res.CanRebalanceToOtherNode.Name},
+		{"Can remain on current node", res.CanRemainOnCurrentNode.Name},
+	}
+
+	if err := table.PrintMarkdown(); err != nil {
+		return err
+	}
+
+	return nil
+}

pkg/es/snapshot.go

@@ -117,7 +117,7 @@ func SnapshotShow(conf *cfg.Config, snapshot string) error {
 	}
 
 	table := NewTable(2, 17)
-	table.Addheaders("field", "value")
+	table.Addheaders("snapshot property", "value")
 
 	snap := res.Snapshots[0]