From a88325cb96cd20a25e9191f842b257087d2e36ac Mon Sep 17 00:00:00 2001
From: Ken Hibino <ken.hibino7@gmail.com>
Date: Tue, 1 Sep 2020 06:57:08 -0700
Subject: [PATCH] Add ClusterNodes and ClusterKeySlot in Inspector

---
 inspector.go            | 27 +++++++++++++++++++++++++++
 internal/rdb/inspect.go | 24 ++++++++++++++++++++++++
 2 files changed, 51 insertions(+)

diff --git a/inspector.go b/inspector.go
index 2d5c7d6..fa4abf7 100644
--- a/inspector.go
+++ b/inspector.go
@@ -573,3 +573,30 @@ func (i *Inspector) UnpauseQueue(qname string) error {
 	}
 	return i.rdb.Unpause(qname)
 }
+
+// ClusterKeySlot returns an integer identifying the hash slot the given queue hashes to.
+func (i *Inspector) ClusterKeySlot(qname string) (int64, error) {
+	return i.rdb.ClusterKeySlot(qname)
+}
+
+// ClusterNode describes a node in redis cluster.
+type ClusterNode struct {
+	// Node ID in the cluster.
+	ID string
+
+	// Address of the node.
+	Addr string
+}
+
+// ClusterNode returns a list of nodes the given queue belongs to.
+func (i *Inspector) ClusterNodes(qname string) ([]ClusterNode, error) {
+	nodes, err := i.rdb.ClusterNodes(qname)
+	if err != nil {
+		return nil, err
+	}
+	var res []ClusterNode
+	for _, node := range nodes {
+		res = append(res, ClusterNode{ID: node.ID, Addr: node.Addr})
+	}
+	return res, nil
+}
diff --git a/internal/rdb/inspect.go b/internal/rdb/inspect.go
index 9bc1268..7634679 100644
--- a/internal/rdb/inspect.go
+++ b/internal/rdb/inspect.go
@@ -830,3 +830,27 @@ func (r *RDB) Unpause(qname string) error {
 	}
 	return nil
 }
+
+// ClusterKeySlot returns an integer identifying the hash slot the given queue hashes to.
+func (r *RDB) ClusterKeySlot(qname string) (int64, error) {
+	key := base.QueueKey(qname)
+	return r.client.ClusterKeySlot(key).Result()
+}
+
+// ClusterNodes returns a list of nodes the given queue belongs to.
+func (r *RDB) ClusterNodes(qname string) ([]redis.ClusterNode, error) {
+	keyslot, err := r.ClusterKeySlot(qname)
+	if err != nil {
+		return nil, err
+	}
+	clusterSlots, err := r.client.ClusterSlots().Result()
+	if err != nil {
+		return nil, err
+	}
+	for _, slotRange := range clusterSlots {
+		if int64(slotRange.Start) <= keyslot && keyslot <= int64(slotRange.End) {
+			return slotRange.Nodes, nil
+		}
+	}
+	return nil, fmt.Errorf("nodes not found")
+}