Reset pod and namespace watch retry count and backoff interval on successful events and add unit tests.

lib/fluent/plugin/kubernetes_metadata_watch_namespaces.rb

@@ -29,7 +29,6 @@ def set_up_namespace_thread
       # the configuration.
       namespace_watcher = start_namespace_watch
       Thread.current[:namespace_watch_retry_backoff_interval] = @watch_retry_interval
-      Thread.current[:namespace_watch_retry_count] = 0
 
       # Any failures / exceptions in the followup watcher notice
       # processing will be swallowed and retried. These failures /
@@ -96,11 +95,19 @@ def get_namespaces_and_start_watcher
       watcher
     end
 
+    # Reset namespace watch retry count and backoff interval as there is a
+    # successful watch notice.
+    def reset_namespace_watch_retry_stats
+      Thread.current[:namespace_watch_retry_count] = 0
+      Thread.current[:namespace_watch_retry_backoff_interval] = @watch_retry_interval
+    end
+
     # Process a watcher notice and potentially raise an exception.
     def process_namespace_watcher_notices(watcher)
       watcher.each do |notice|
         case notice.type
           when 'MODIFIED'
+            reset_namespace_watch_retry_stats
             cache_key = notice.object['metadata']['uid']
             cached    = @namespace_cache[cache_key]
             if cached
@@ -110,13 +117,16 @@ def process_namespace_watcher_notices(watcher)
               @stats.bump(:namespace_cache_watch_misses)
             end
           when 'DELETED'
+            reset_namespace_watch_retry_stats
             # ignore and let age out for cases where
             # deleted but still processing logs
             @stats.bump(:namespace_cache_watch_deletes_ignored)
           when 'ERROR'
+            @stats.bump(:namespace_watch_error_type_notices)
             message = notice['object']['message'] if notice['object'] && notice['object']['message']
             raise "Error while watching namespaces: #{message}"
           else
+            reset_namespace_watch_retry_stats
             # Don't pay attention to creations, since the created namespace may not
             # be used by any namespace on this node.
             @stats.bump(:namespace_cache_watch_ignored)

lib/fluent/plugin/kubernetes_metadata_watch_pods.rb

@@ -98,12 +98,19 @@ def get_pods_and_start_watcher
       watcher
     end
 
+    # Reset pod watch retry count and backoff interval as there is a
+    # successful watch notice.
+    def reset_pod_watch_retry_stats
+      Thread.current[:pod_watch_retry_count] = 0
+      Thread.current[:pod_watch_retry_backoff_interval] = @watch_retry_interval
+    end
+
     # Process a watcher notice and potentially raise an exception.
     def process_pod_watcher_notices(watcher)
       watcher.each do |notice|
         case notice.type
           when 'MODIFIED'
-            Thread.current[:pod_watch_retry_count] = 0
+            reset_pod_watch_retry_stats
             cache_key = notice.object['metadata']['uid']
             cached    = @cache[cache_key]
             if cached
@@ -116,15 +123,16 @@ def process_pod_watcher_notices(watcher)
               @stats.bump(:pod_cache_watch_misses)
             end
           when 'DELETED'
-            Thread.current[:pod_watch_retry_count] = 0
+            reset_pod_watch_retry_stats
             # ignore and let age out for cases where pods
             # deleted but still processing logs
             @stats.bump(:pod_cache_watch_delete_ignored)
           when 'ERROR'
+            @stats.bump(:pod_watch_error_type_notices)
             message = notice['object']['message'] if notice['object'] && notice['object']['message']
             raise "Error while watching pods: #{message}"
           else
-            Thread.current[:pod_watch_retry_count] = 0
+            reset_pod_watch_retry_stats
             # Don't pay attention to creations, since the created pod may not
             # end up on this node.
             @stats.bump(:pod_cache_watch_ignored)

test/plugin/test_watch_namespaces.rb

@@ -70,6 +70,12 @@ class WatchNamespacesTestTest < WatchTest
             }
          }
        )
+       @error = OpenStruct.new(
+         type: 'ERROR',
+         object: {
+           'message' => 'some error message'
+         }
+       )
      end
 
     test 'namespace list caches namespaces' do
@@ -137,6 +143,39 @@ class WatchNamespacesTestTest < WatchTest
           assert_equal(3, @stats[:namespace_watch_failures])
           assert_equal(2, Thread.current[:namespace_watch_retry_count])
           assert_equal(4, Thread.current[:namespace_watch_retry_backoff_interval])
+          assert_nil(@stats[:namespace_watch_error_type_notices])
+        end
+      end
+    end
+
+    test 'namespace watch retries when error is received' do
+      @client.stub :get_namespaces, @initial do
+        @client.stub :watch_namespaces, [@error] do
+          assert_raise Fluent::UnrecoverableError do
+            set_up_namespace_thread
+          end
+          assert_equal(3, @stats[:namespace_watch_failures])
+          assert_equal(2, Thread.current[:namespace_watch_retry_count])
+          assert_equal(4, Thread.current[:namespace_watch_retry_backoff_interval])
+          assert_equal(3, @stats[:namespace_watch_error_type_notices])
+        end
+      end
+    end
+
+    test 'namespace watch continues after retries succeed' do
+      @client.stub :get_namespaces, @initial do
+        @client.stub :watch_namespaces, [@modified, @error, @modified] do
+          # Force the infinite watch loop to exit after 3 seconds. Verifies that
+          # no unrecoverable error was thrown during this period of time.
+          assert_raise Timeout::Error.new('execution expired') do
+            Timeout.timeout(3) do
+              set_up_namespace_thread
+            end
+          end
+          assert_operator(@stats[:namespace_watch_failures], :>=, 3)
+          assert_operator(Thread.current[:namespace_watch_retry_count], :<=, 1)
+          assert_operator(Thread.current[:namespace_watch_retry_backoff_interval], :<=, 1)
+          assert_operator(@stats[:namespace_watch_error_type_notices], :>=, 3)
         end
       end
     end

test/plugin/test_watch_pods.rb

@@ -136,6 +136,12 @@ class DefaultPodWatchStrategyTest < WatchTest
             }
          }
        )
+       @error = OpenStruct.new(
+         type: 'ERROR',
+         object: {
+           'message' => 'some error message'
+         }
+       )
      end
 
     test 'pod list caches pods' do
@@ -219,6 +225,39 @@ class DefaultPodWatchStrategyTest < WatchTest
           assert_equal(3, @stats[:pod_watch_failures])
           assert_equal(2, Thread.current[:pod_watch_retry_count])
           assert_equal(4, Thread.current[:pod_watch_retry_backoff_interval])
+          assert_nil(@stats[:pod_watch_error_type_notices])
+        end
+      end
+    end
+
+    test 'pod watch retries when error is received' do
+      @client.stub :get_pods, @initial do
+        @client.stub :watch_pods, [@error] do
+          assert_raise Fluent::UnrecoverableError do
+            set_up_pod_thread
+          end
+          assert_equal(3, @stats[:pod_watch_failures])
+          assert_equal(2, Thread.current[:pod_watch_retry_count])
+          assert_equal(4, Thread.current[:pod_watch_retry_backoff_interval])
+          assert_equal(3, @stats[:pod_watch_error_type_notices])
+        end
+      end
+    end
+
+    test 'pod watch continues after retries succeed' do
+      @client.stub :get_pods, @initial do
+        @client.stub :watch_pods, [@modified, @error, @modified] do
+          # Force the infinite watch loop to exit after 3 seconds. Verifies that
+          # no unrecoverable error was thrown during this period of time.
+          assert_raise Timeout::Error.new('execution expired') do
+            Timeout.timeout(3) do
+              set_up_pod_thread
+            end
+          end
+          assert_operator(@stats[:pod_watch_failures], :>=, 3)
+          assert_operator(Thread.current[:pod_watch_retry_count], :<=, 1)
+          assert_operator(Thread.current[:pod_watch_retry_backoff_interval], :<=, 1)
+          assert_operator(@stats[:pod_watch_error_type_notices], :>=, 3)
         end
       end
     end

test/plugin/watch_test.rb

@@ -33,6 +33,8 @@ def thread_current_running?
     @watch_retry_exponential_backoff_base = 2
     @cache = {}
     @stats = KubernetesMetadata::Stats.new
+    Thread.current[:pod_watch_retry_count] = 0
+    Thread.current[:namespace_watch_retry_count] = 0
 
     @client = OpenStruct.new
     def @client.resourceVersion