Add support for refreshing bearer token

docker/Gemfile

@@ -6,7 +6,6 @@ source 'https://rubygems.org'
 gem "fluentd", ">=1.14.2"
 gem "fluent-plugin-prometheus", ">=2.0"
 gem "fluent-plugin-record-modifier", "=2.1.0"
-gem "fluent-plugin-kubernetes_metadata_filter", ">=2.5.3"
 gem "fluent-plugin-jq", "=0.5.1"
 gem "oj", "=3.10.18"
 gem 'multi_json', '=1.14.1'

docker/Gemfile.lock

@@ -35,10 +35,6 @@ GEM
     fluent-plugin-jq (0.5.1)
       fluentd (>= 0.14.10, < 2)
       multi_json (~> 1.13)
-    fluent-plugin-kubernetes_metadata_filter (2.9.3)
-      fluentd (>= 0.14.0, < 1.15)
-      kubeclient (>= 4.0.0, < 5.0.0)
-      lru_redux
     fluent-plugin-prometheus (2.0.2)
       fluentd (>= 1.9.1, < 2)
       prometheus-client (>= 2.1.0)
@@ -88,7 +84,6 @@ GEM
       jsonpath (~> 1.0)
       recursive-open-struct (~> 1.1, >= 1.1.1)
       rest-client (~> 2.0)
-    lru_redux (1.1.0)
     mail (2.7.1)
       mini_mime (>= 0.1.1)
     mime-types (3.4.1)
@@ -162,7 +157,6 @@ DEPENDENCIES
   bigdecimal (= 3.0.0)
   fluent-plugin-jq (= 0.5.1)
   fluent-plugin-kubernetes-metrics!
-  fluent-plugin-kubernetes_metadata_filter (>= 2.5.3)
   fluent-plugin-prometheus (>= 2.0)
   fluent-plugin-record-modifier (= 2.1.0)
   fluent-plugin-splunk-hec (>= 1.2.5)

lib/fluent/plugin/in_kubernetes_metrics.rb

@@ -166,7 +166,7 @@ def init_without_kubeconfig(_options = {})
         }
 
         auth_options = {}
-        auth_options[:bearer_token] = File.read(@bearer_token_file) if @bearer_token_file
+        auth_options[:bearer_token_file] = @bearer_token_file if @bearer_token_file
 
         @client = Kubeclient::Client.new(
           @kubernetes_url, 'v1',
@@ -244,6 +244,11 @@ def set_ssl_options
         ssl_options
       end
 
+      # This method is used to refresh the authorization token for kubeclient
+      def update_kubeclient_header
+        @client.headers[:Authorization] = 'Bearer ' + File.read(@bearer_token_file) if @bearer_token_file
+      end
+
       # This method is used to set the options for sending a request to the kubelet api
       def request_options
         options = { method: 'get', url: @kubelet_url }
@@ -677,6 +682,7 @@ def scrape_metrics
           response = RestClient::Request.execute request_options
           handle_response(response)
         else
+          update_kubeclient_header
           @node_names.each do |node|
             response = summary_proxy_api(node).get(@client.headers)
             handle_response(response)
@@ -688,6 +694,7 @@ def is_stats_endpoint_available?
         if @use_rest_client
           response_stats = RestClient::Request.execute request_options_stats
         else
+          update_kubeclient_header
           @node_names.each do |node|
             @node_name = node
             response_stats = stats_proxy_api(node).get(@client.headers)
@@ -703,6 +710,7 @@ def scrape_stats_metrics
           response_stats = RestClient::Request.execute request_options_stats
           handle_stats_response(response_stats)
         else
+          update_kubeclient_header
           @node_names.each do |node|
             @node_name = node
             response_stats = stats_proxy_api(node).get(@client.headers)
@@ -716,6 +724,7 @@ def scrape_cadvisor_metrics
           response_cadvisor = RestClient::Request.execute cadvisor_request_options
           handle_cadvisor_response(response_cadvisor)
         else
+          update_kubeclient_header
           @node_names.each do |node|
             response_cadvisor = cadvisor_proxy_api(node).get(@client.headers)
             handle_cadvisor_response(response_cadvisor)