system.rb in cosmos-3.3.1

- old
+ new

@@ -60,20 +60,20 @@
     KNOWN_PORTS = ['CTS_API', 'TLMVIEWER_API', 'CTS_PREIDENTIFIED']
     # Known COSMOS paths
     KNOWN_PATHS = ['LOGS', 'TMP', 'SAVED_CONFIG', 'TABLES', 'HANDBOOKS', 'PROCEDURES']
 
     @@instance = nil
+    @@instance_mutex = Mutex.new
 
     # Create a new System object. Note, this should not be called directly but
     # you should instead use System.instance and treat this class as a
     # singleton.
     #
     # @param filename [String] Full path to the system configuration file to
     #   read. Be default this is <Cosmos::USERPATH>/config/system/system.txt
     def initialize(filename = nil)
       raise "Cosmos::System created twice" unless @@instance.nil?
-      @@instance = self
       @targets = {}
       @targets['UNKNOWN'] = Target.new('UNKNOWN')
       @config = nil
       @commands = nil
       @telemetry = nil
@@ -113,10 +113,11 @@
       process_file(filename)
       ENV['COSMOS_LOGS_DIR'] = @paths['LOGS']
 
       @initial_filename = filename
       @initial_config = nil
+      @@instance = self
     end
 
     # @return [String] Configuration name
     def self.configuration_name
       # In order not to make the @config instance variable accessable to the
@@ -192,11 +193,14 @@
       self.instance.limits_set = limits_set
     end
 
     # @return [System] The System singleton
     def self.instance(filename = nil)
-      @@instance ||= self.new(filename)
-      return @@instance
+      return @@instance if @@instance
+      @@instance_mutex.synchronize do
+        @@instance ||= self.new(filename)
+        return @@instance
+      end
     end
 
     # Process the system.txt configuration file
     #
     # @param filename [String] The configuration file