From d94f140574a5035159cf62a2d6898fa044d10891 Mon Sep 17 00:00:00 2001
From: Stephen von Takach <steve@vontaka.ch>
Date: Thu, 11 Apr 2024 19:14:02 +1000
Subject: [PATCH] feat: expose ulid to uri mappings

---
 shard.yml                                         | 2 +-
 spec/lookup_spec.cr                               | 5 +++++
 spec/manager_spec.cr                              | 4 ++++
 src/redis_service_manager.cr                      | 6 +++---
 src/redis_service_manager/clustering.cr           | 7 +++++++
 src/redis_service_manager/clustering/discovery.cr | 5 +++++
 6 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/shard.yml b/shard.yml
index 44a8858..a2e2964 100644
--- a/shard.yml
+++ b/shard.yml
@@ -1,5 +1,5 @@
 name: redis_service_manager
-version: 3.0.0
+version: 3.1.0
 
 dependencies:
   ulid:
diff --git a/spec/lookup_spec.cr b/spec/lookup_spec.cr
index 248ff34..5d400e2 100644
--- a/spec/lookup_spec.cr
+++ b/spec/lookup_spec.cr
@@ -63,6 +63,11 @@ describe RedisServiceManager do
       URI.parse("http://node2/node2"),
     ]
 
+    lookup_local.node_hash.should eq({
+      node1.ulid => URI.parse("http://node1/node1"),
+      node2.ulid => URI.parse("http://node2/node2"),
+    })
+
     node2.unregister
     node1.unregister
   end
diff --git a/spec/manager_spec.cr b/spec/manager_spec.cr
index 2f25919..b0b0b88 100644
--- a/spec/manager_spec.cr
+++ b/spec/manager_spec.cr
@@ -292,6 +292,10 @@ describe RedisServiceManager do
     node2.leader?.should be_true
     node2.cluster_ready?.should be_true
     leader.should eq("node2")
+    node2.node_hash.should eq({
+      node2.ulid => URI.parse(node2.uri),
+      node3.ulid => URI.parse(node3.uri),
+    })
 
     node2.unregister
     node3.unregister
diff --git a/src/redis_service_manager.cr b/src/redis_service_manager.cr
index 02aa0ec..5f1a4df 100644
--- a/src/redis_service_manager.cr
+++ b/src/redis_service_manager.cr
@@ -27,7 +27,6 @@ class RedisServiceManager < Clustering
     @node_info = NodeInfo.new(@uri, "")
   end
 
-  getter version : String = ""
   getter? registered : Bool = false
   getter? watching : Bool = false
 
@@ -47,8 +46,9 @@ class RedisServiceManager < Clustering
     node_keys.size
   end
 
-  def cluster_nodes
-    @hash.to_h
+  def node_hash : Hash(String, URI)
+    hash = @lock.synchronize { @hash.to_h }.transform_keys(&.split("}.", 2)[1])
+    hash.transform_values { |uri| URI.parse(uri) }
   end
 
   def register : Bool
diff --git a/src/redis_service_manager/clustering.cr b/src/redis_service_manager/clustering.cr
index 2348e65..4b140e2 100644
--- a/src/redis_service_manager/clustering.cr
+++ b/src/redis_service_manager/clustering.cr
@@ -10,6 +10,7 @@ abstract class Clustering
 
   # the name of the service you are clustering
   getter service : String
+  getter version : String = ""
 
   getter rebalance_callbacks : Array((RendezvousHash, RebalanceComplete) ->)
   getter cluster_stable_callbacks : Array(->)
@@ -17,6 +18,9 @@ abstract class Clustering
   # the service uri for this host
   abstract def uri : String
 
+  # the id of the node
+  abstract def ulid : String
+
   # Called when the cluster has changed
   def on_rebalance(&callback : (RendezvousHash, RebalanceComplete) ->)
     rebalance_callbacks << callback
@@ -44,6 +48,9 @@ abstract class Clustering
 
   # returns the list of known nodes
   abstract def rendezvous : RendezvousHash
+
+  # returns a node_id => URI mapping
+  abstract def node_hash : Hash(String, URI)
 end
 
 require "./clustering/*"
diff --git a/src/redis_service_manager/clustering/discovery.cr b/src/redis_service_manager/clustering/discovery.cr
index 98a0d5b..e600105 100644
--- a/src/redis_service_manager/clustering/discovery.cr
+++ b/src/redis_service_manager/clustering/discovery.cr
@@ -67,6 +67,11 @@ class Clustering::Discovery
     rendezvous.nodes.map { |node| URI.parse(node) }
   end
 
+  # Returns the list of node IDs => URI mapping
+  def node_hash : Hash(String, URI)
+    @cluster.node_hash
+  end
+
   protected def update_node_list(rendezvous : RendezvousHash)
     @rendezvous = rendezvous
     @last_updated = Time.utc