Moved from misused constants to class variables in MetricsCollector, MetricsCollector is no longer initialized as a singleton

src/invidious.cr

@@ -170,7 +170,7 @@ end
 
 if CONFIG.statistics_enabled
   Invidious::Jobs.register Invidious::Jobs::StatisticsRefreshJob.new(PG_DB, SOFTWARE)
-  add_handler Metrics::METRICS_COLLECTOR
+  add_handler Metrics::RouteMetricsCollector.new
 end
 
 if (CONFIG.use_pubsub_feeds.is_a?(Bool) && CONFIG.use_pubsub_feeds.as(Bool)) || (CONFIG.use_pubsub_feeds.is_a?(Int32) && CONFIG.use_pubsub_feeds.as(Int32) > 0)

src/invidious/metrics.cr

@@ -3,20 +3,18 @@
 module Metrics
   record MetricLabels, request_method : String, request_route : String, response_code : Int32
 
-  # Counts how many a given route was used
-  REQUEST_COUNTERS = Hash(MetricLabels, Int64).new
-
-  # Counts how much time was used to handle requests to each route
-  REQUEST_DURATION_SECONDS_SUMS = Hash(MetricLabels, Float32).new
-
-  # The handler which will record metrics when registered in a Kemal application
-  METRICS_COLLECTOR = RouteMetricsCollector.new(REQUEST_COUNTERS, REQUEST_DURATION_SECONDS_SUMS)
-
   class RouteMetricsCollector < Kemal::Handler
-    def initialize(
-      @num_of_request_counters : Hash(MetricLabels, Int64),
-      @request_duration_seconds_sums : Hash(MetricLabels, Float32)
-    )
+    # Counts how many times a given route was used
+    @@num_of_request_counters = Hash(MetricLabels, Int64).new
+    # Counts how much time was used to handle requests to each route
+    @@request_duration_seconds_sums = Hash(MetricLabels, Float32).new
+
+    def self.num_of_request_counters
+      return @@num_of_request_counters
+    end
+
+    def self.request_duration_seconds_sums
+      return @@request_duration_seconds_sums
     end
 
     def call(context : HTTP::Server::Context)
@@ -33,15 +31,15 @@ module Metrics
         LOGGER.trace("Collecting metrics: handling #{request_method} #{request_path} took #{seconds_spent_handling}s and finished with status #{response_status}")
         metric_key = MetricLabels.new request_path, request_method, response_status
 
-        unless @num_of_request_counters.has_key?(metric_key)
-          @num_of_request_counters[metric_key] = 0
+        unless @@num_of_request_counters.has_key?(metric_key)
+          @@num_of_request_counters[metric_key] = 0
         end
-        @num_of_request_counters[metric_key] += 1
+        @@num_of_request_counters[metric_key] += 1
 
-        unless @request_duration_seconds_sums.has_key?(metric_key)
-          @request_duration_seconds_sums[metric_key] = 0.0
+        unless @@request_duration_seconds_sums.has_key?(metric_key)
+          @@request_duration_seconds_sums[metric_key] = 0.0
         end
-        @request_duration_seconds_sums[metric_key] += seconds_spent_handling
+        @@request_duration_seconds_sums[metric_key] += seconds_spent_handling
       end
     end
   end

src/invidious/routes/api/v1/misc.cr

@@ -32,7 +32,7 @@ module Invidious::Routes::API::V1::Misc
     env.response.content_type = "text/plain"
 
     return String.build do |str|
-      Metrics::REQUEST_COUNTERS.each do |metric_labels, value|
+      Metrics::RouteMetricsCollector.num_of_request_counters.each do |metric_labels, value|
         str << "http_requests_total{"
         str << "method=\"" << metric_labels.request_method << "\" "
         str << "route=\"" << metric_labels.request_route << "\" "
@@ -41,7 +41,7 @@ module Invidious::Routes::API::V1::Misc
         str << value << "\n"
       end
 
-      Metrics::REQUEST_DURATION_SECONDS_SUMS.each do |metric_labels, value|
+      Metrics::RouteMetricsCollector.request_duration_seconds_sums.each do |metric_labels, value|
         str << "http_request_duration_seconds_sum{"
         str << "method=\"" << metric_labels.request_method << "\" "
         str << "route=\"" << metric_labels.request_route << "\" "