mmaped_value.rb in prometheus-client-mmap-0.7.0.beta35

- old
+ new

@@ -4,12 +4,13 @@
 
 module Prometheus
   module Client
     # A float protected by a mutex backed by a per-process mmaped file.
     class MmapedValue
-      @@files = {}
       VALUE_LOCK = Mutex.new
+
+      @@files = {}
       @@pid = -1
 
       def initialize(type, metric_name, name, labels, multiprocess_mode = '')
         @file_prefix = type.to_s
         @metric_name = metric_name
@@ -23,11 +24,11 @@
 
         @mutex = Mutex.new
         initialize_file
       end
 
-      def increment(amount=1)
+      def increment(amount = 1)
         @mutex.synchronize do
           initialize_file if pid_changed?
 
           @value += amount
           write_value(@key, @value)
@@ -54,39 +55,23 @@
 
       def pid_changed?
         @pid != Process.pid
       end
 
-      def reinitialize
-        initialize_file if pid_changed?
+      # method needs to be run in VALUE_LOCK mutex
+      def unsafe_reinitialize_file(check_pid = true)
+        unsafe_initialize_file if !check_pid || pid_changed?
       end
 
-      def initialize_file
+      def self.reset_and_reinitialize
         VALUE_LOCK.synchronize do
-          return if @file && !pid_changed?
-          self.class.reset_on_pid_change
+          @@pid = Process.pid
+          @@files = {}
 
-          @pid = Process.pid
-          unless @@files.has_key?(@file_prefix)
-            unless @file.nil?
-              @file.close
-            end
-            mmaped_file = Helper::MmapedFile.open_exclusive_file(@file_prefix)
-
-            @@files[@file_prefix] = MmapedDict.new(mmaped_file)
+          ObjectSpace.each_object(MmapedValue).each do |v|
+            v.unsafe_reinitialize_file(false)
           end
-
-          @file = @@files[@file_prefix]
-          labelnames = []
-          labelvalues = []
-          @labels.each do |k, v|
-            labelnames << k
-            labelvalues << v
-          end
-
-          @key = [@metric_name, @name, labelnames, labelvalues].to_json
-          @value = read_value(@key)
         end
       end
 
       def self.reset_on_pid_change
         if pid_changed?
@@ -96,13 +81,13 @@
       end
 
       def self.reinitialize_on_pid_change
         VALUE_LOCK.synchronize do
           reset_on_pid_change
-        end
 
-        ObjectSpace.each_object(MmapedValue, &:reinitialize)
+          ObjectSpace.each_object(MmapedValue, &:unsafe_reinitialize_file)
+        end
       end
 
       def self.pid_changed?
         @@pid != Process.pid
       end
@@ -111,12 +96,48 @@
         true
       end
 
       private
 
+      def initialize_file
+        VALUE_LOCK.synchronize do
+          unsafe_initialize_file
+        end
+      end
+
+      def unsafe_initialize_file
+        self.class.reset_on_pid_change
+
+        @pid = Process.pid
+        unless @@files.has_key?(@file_prefix)
+          unless @file.nil?
+            @file.close
+          end
+          mmaped_file = Helper::MmapedFile.open_exclusive_file(@file_prefix)
+
+          @@files[@file_prefix] = MmapedDict.new(mmaped_file)
+        end
+
+        @file = @@files[@file_prefix]
+        @key = rebuild_key
+
+        @value = read_value(@key)
+      end
+
+
+      def rebuild_key
+        labelnames = []
+        labelvalues = []
+        @labels.each do |k, v|
+          labelnames << k
+          labelvalues << v
+        end
+
+        [@metric_name, @name, labelnames, labelvalues].to_json
+      end
+
       def write_value(key, val)
         @file.write_value(key, val)
-
       rescue StandardError => e
         Prometheus::Client.logger.warn("writing value to #{@file.path} failed with #{e}")
         Prometheus::Client.logger.debug(e.backtrace.join("\n"))
       end
 