mv index allocate to shard allocate, add explanations, fixes #71 (#75)

cmd/shards.go

@@ -35,6 +35,7 @@ func Shard(conf *cfg.Config) *cli.Command {
 		Commands: []*cli.Command{
 			ShardList(conf),
 			ShardShow(conf),
+			ShardAllocation(conf),
 		},
 	}
 }
@@ -94,3 +95,41 @@ func ShardShow(conf *cfg.Config) *cli.Command {
 		},
 	}
 }
+
+func ShardAllocation(conf *cfg.Config) *cli.Command {
+	return &cli.Command{
+		Name:    "allocation",
+		Aliases: []string{"a"},
+		Usage:   "explain shard 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"},
+			},
+			&cli.StringFlag{
+				Name:        "node",
+				Usage:       "explain a shard only if it is currently located on the specified node name or node ID",
+				Destination: &conf.FromNode,
+				Aliases:     []string{"n"},
+			},
+		},
+
+		Action: func(ctx context.Context, cmd *cli.Command) error {
+			index := cmd.Args().Get(0)
+			if index == "" {
+				return errors.New("no index specified")
+			}
+
+			return es.ShardAllocation(conf, cmd.Args().Get(0))
+		},
+	}
+}