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lib/strategy/kubernetes.ex

@@ -25,7 +25,7 @@ defmodule Cluster.Strategy.Kubernetes do
      - `:kubernetes_selector`
      - `:kubernetes_service_name`
      - `:kubernetes_ip_lookup_mode`
-     - `:kubernetes_resource_version`
+     - `:kubernetes_use_cached_resources`
      - `:mode`
 
   ## Getting `<basename>`
@@ -71,12 +71,11 @@ defmodule Cluster.Strategy.Kubernetes do
 
   Then, this strategy will fetch the IP of all pods with that label and attempt to connect.
 
-  ### `kubernetes_resource_version` option
+  ### `kubernetes_use_cached_resources` option
 
-  When setting this value, this strategy will use given resource version value to fetch k8s resources,
-  where each modification of the resource increments the resource version.
-
-  If set to `0` kubernetes will use cached version, that may be outdated.
+  When setting this value, this strategy will use cached resource version value to fetch k8s resources.
+  In k8s resources are incremented by 1 on every change, this version will set requested resourceVersion
+  to 0, that will use cached versions of resources, take in mind that this may be outdated or unavailable.
 
   ### `:mode` option
 
@@ -368,7 +367,9 @@ defmodule Cluster.Strategy.Kubernetes do
     service_name = Keyword.get(config, :kubernetes_service_name)
     selector = Keyword.fetch!(config, :kubernetes_selector)
     ip_lookup_mode = Keyword.get(config, :kubernetes_ip_lookup_mode, :endpoints)
-    resource_version = Keyword.get(config, :kubernetes_resource_version, nil)
+
+    use_cache = Keyword.get(config, :kubernetes_use_cached_resources, false)
+    resource_version = if use_cache, do: 0, else: nil
 
     master_name = Keyword.get(config, :kubernetes_master, @kubernetes_master)
     cluster_domain = System.get_env("CLUSTER_DOMAIN", "#{cluster_name}.local")

test/kubernetes_test.exs

@@ -81,7 +81,7 @@ defmodule Cluster.Strategy.KubernetesTest do
       end
     end
 
-    test "works with resource version" do
+    test "works with cached resources" do
       use_cassette "kubernetes", custom: true do
         capture_log(fn ->
           start_supervised!({Kubernetes,
@@ -91,7 +91,34 @@ defmodule Cluster.Strategy.KubernetesTest do
                config: [
                  kubernetes_node_basename: "test_basename",
                  kubernetes_selector: "app=test_selector",
-                 kubernetes_resource_version: 0,
+                 kubernetes_use_cached_resources: true,
+                 # If you want to run the test freshly, you'll need to create a DNS Entry
+                 kubernetes_master: "cluster.localhost.",
+                 kubernetes_service_account_path:
+                   Path.join([__DIR__, "fixtures", "kubernetes", "service_account"])
+               ],
+               connect: {Nodes, :connect, [self()]},
+               disconnect: {Nodes, :disconnect, [self()]},
+               list_nodes: {Nodes, :list_nodes, [[]]}
+             }
+           ]})
+
+          assert_receive {:connect, _}, 5_000
+        end)
+      end
+    end
+
+    test "works with no cached resources" do
+      use_cassette "kubernetes", custom: true do
+        capture_log(fn ->
+          start_supervised!({Kubernetes,
+           [
+             %Cluster.Strategy.State{
+               topology: :name,
+               config: [
+                 kubernetes_node_basename: "test_basename",
+                 kubernetes_selector: "app=test_selector",
+                 kubernetes_use_cached_resources: false,
                  # If you want to run the test freshly, you'll need to create a DNS Entry
                  kubernetes_master: "cluster.localhost.",
                  kubernetes_service_account_path:
@@ -228,7 +255,7 @@ defmodule Cluster.Strategy.KubernetesTest do
       end
     end
 
-    test "works with pods and resource version" do
+    test "works with pods and cached resources" do
       use_cassette "kubernetes_pods", custom: true do
         capture_log(fn ->
           start_supervised!({Kubernetes,
@@ -241,7 +268,7 @@ defmodule Cluster.Strategy.KubernetesTest do
                  # If you want to run the test freshly, you'll need to create a DNS Entry
                  kubernetes_master: "cluster.localhost.",
                  kubernetes_ip_lookup_mode: :pods,
-                 kubernetes_resource_version: 0,
+                 kubernetes_use_cached_resources: true,
                  kubernetes_service_account_path:
                    Path.join([__DIR__, "fixtures", "kubernetes", "service_account"])
                ],