From: Christopher <chris@entropealabs.com>
Date: Wed, 18 Mar 2020 19:44:05 +0000 (-0500)
Subject: add get_wildcard_key function
X-Git-Url: http://git.entropealabs.com/?a=commitdiff_plain;h=4c36b8d68f40711cd167edb9917d32a992f49561;p=cluster_kv.git

add get_wildcard_key function
---

diff --git a/lib/cluster_kv.ex b/lib/cluster_kv.ex
index dd78437..623dad7 100644
--- a/lib/cluster_kv.ex
+++ b/lib/cluster_kv.ex
@@ -54,6 +54,7 @@ defmodule ClusterKV do
   defdelegate put(name, keyspace, key, value), to: Ring
   defdelegate update(name, keyspace, key, value, fun), to: Ring
   defdelegate batch(name, keyspace, batch), to: Ring
+  defdelegate get_wildcard_key(key, split_on, join, wildcard), to: Ring
   defdelegate put_wildcard(name, keyspace, key, value, split_on, join, wildcard), to: Ring
   defdelegate prefix(name, keyspace, key, split_on, min, timeout \\ :infinity), to: Ring
   defdelegate stream(name, timeout \\ :infinity), to: Ring
diff --git a/lib/cluster_kv/ring.ex b/lib/cluster_kv/ring.ex
index 7733775..27ef1ef 100644
--- a/lib/cluster_kv/ring.ex
+++ b/lib/cluster_kv/ring.ex
@@ -55,6 +55,16 @@ defmodule ClusterKV.Ring do
     :gen_statem.cast(ClusterKV.ring_name(name), {:update, keyspace, key, value, fun})
   end
 
+  @spec get_wildcard_key(
+          key :: String.t(),
+          split_on :: String.t(),
+          join :: String.t(),
+          wildcard :: String.t()
+        ) :: :ok
+  def get_wildcard_key(key, split_on, join, wildcard) do
+    do_get_wildcard_key(key, split_on, wildcard, join)
+  end
+
   @spec put_wildcard(
           name :: module(),
           keyspace :: String.t(),
@@ -463,6 +473,19 @@ defmodule ClusterKV.Ring do
     end)
   end
 
+  defp do_get_wildcard_key(topic, split_on, wildcard, join) do
+    topic
+    |> String.split(split_on)
+    |> Enum.with_index()
+    |> Enum.reduce_while(nil, fn
+      {^wildcard, _}, acc ->
+        {:cont, acc}
+
+      {k, i}, _ ->
+        {:halt, Enum.join([k, i], join)}
+    end)
+  end
+
   @spec redistribute_data(
           name :: module(),
           me :: node(),
diff --git a/test/cluster_kv_test.exs b/test/cluster_kv_test.exs
index 8661262..2537a53 100644
--- a/test/cluster_kv_test.exs
+++ b/test/cluster_kv_test.exs
@@ -22,6 +22,8 @@ defmodule ClusterKVTest do
     ClusterKV.put(db, @keyspace, "test1:test", :cruel)
     ClusterKV.put(db, @keyspace, "test1:test", :world)
 
+    assert "test:1" = ClusterKV.get_wildcard_key(".test.light..status", ".", ":", "")
+
     ClusterKV.put_wildcard(
       db,
       @keyspace,