Merge pull request #1693 from tungmq/dev

Add default MAX_RAND value for length 16 & 32

lib/new_relic/agent/guid_generator.rb

@@ -7,14 +7,23 @@ module Agent
     module GuidGenerator
       module_function
 
+      MAX_RAND_16 = 16**16
+      MAX_RAND_32 = 16**32
       # This method intentionally does not use SecureRandom, because it relies
       # on urandom, which raises an exception in MRI when the interpreter runs
       # out of allocated file descriptors.
       # The guids generated by this method may not be _secure_, but they are
       # random enough for our purposes.
       def generate_guid(length = 16)
-        guid = rand(16**length).to_s(16)
-        guid.length < length ? guid.rjust(length, "0") : guid
+        guid = case length
+               when 16
+                 rand(MAX_RAND_16)
+               when 32
+                 rand(MAX_RAND_32)
+               else
+                 rand(16**length)
+        end.to_s(16)
+        guid.length < length ? guid.rjust(length, '0') : guid
       end
     end
   end