Replace string literals with symbols or frozen strings

lib/datadog/statsd.rb

@@ -24,22 +24,23 @@ class Statsd
 
     # Create a dictionary to assign a key to every parameter's name, except for tags (treated differently)
     # Goal: Simple and fast to add some other parameters
-    OPTS_KEYS = [
-          ['date_happened', 'd'],
-          ['hostname', 'h'],
-          ['aggregation_key', 'k'],
-          ['priority', 'p'],
-          ['source_type_name', 's'],
-          ['alert_type', 't']
-    ]
+    OPTS_KEYS = {
+      :date_happened     => :d,
+      :hostname          => :h,
+      :aggregation_key   => :k,
+      :priority          => :p,
+      :source_type_name  => :s,
+      :alert_type        => :t,
+    }
 
     # Service check options
-    SC_OPT_KEYS = [
-          ['timestamp', 'd:'],
-          ['hostname', 'h:'],
-          ['tags', '#'],
-          ['message', 'm:']
-    ]
+    SC_OPT_KEYS = {
+      :timestamp  => 'd:'.freeze,
+      :hostname   => 'h:'.freeze,
+      :tags       => '#'.freeze,
+      :message    => 'm:'.freeze,
+    }
+
     OK        = 0
     WARNING   = 1
     CRITICAL  = 2
@@ -90,15 +91,15 @@ def initialize(host = DEFAULT_HOST, port = DEFAULT_PORT, opts = {}, max_buffer_s
 
     def namespace=(namespace) #:nodoc:
       @namespace = namespace
-      @prefix = namespace.nil? ? nil : "#{namespace}."
+      @prefix = namespace.nil? ? nil : "#{namespace}.".freeze
     end
 
     def host=(host) #:nodoc:
-      @host = host || '127.0.0.1'
+      @host = host || DEFAULT_HOST
     end
 
     def port=(port) #:nodoc:
-      @port = port || 8125
+      @port = port || DEFAULT_PORT
     end
 
     def tags=(tags) #:nodoc:
@@ -234,23 +235,24 @@ def service_check(name, status, opts={})
       service_check_string = format_service_check(name, status, opts)
       send_to_socket service_check_string
     end
+
     def format_service_check(name, status, opts={})
       sc_string = "_sc|#{name}|#{status}"
 
-      SC_OPT_KEYS.each do |name_key|
-        if opts[name_key[0].to_sym]
-          if name_key[0] == 'tags'
-            tags = opts[:tags].map {|tag| escape_tag_content(tag) }
-            tags = "#{tags.join(",")}" unless tags.empty?
-            sc_string << "|##{tags}"
-          elsif name_key[0] == 'message'
-            message = remove_pipes(opts[:message])
-            escaped_message = escape_service_check_message(message)
-            sc_string << "|m:#{escaped_message}"
-          else
-            value = remove_pipes(opts[name_key[0].to_sym])
-            sc_string << "|#{name_key[1]}#{value}"
-          end
+      SC_OPT_KEYS.each do |key, shorthand_key|
+        next unless opts[key]
+
+        if key == :tags
+          tags = opts[:tags].map {|tag| escape_tag_content(tag) }
+          tags = "#{tags.join(COMMA)}" unless tags.empty?
+          sc_string << "|##{tags}"
+        elsif key == :message
+          message = remove_pipes(opts[:message])
+          escaped_message = escape_service_check_message(message)
+          sc_string << "|m:#{escaped_message}"
+        else
+          value = remove_pipes(opts[key])
+          sc_string << "|#{shorthand_key}#{value}"
         end
       end
       return sc_string
@@ -303,38 +305,51 @@ def format_event(title, text, opts={})
 
       # We construct the string to be sent by adding '|key:value' parts to it when needed
       # All pipes ('|') in the metadata are removed. Title and Text can keep theirs
-      OPTS_KEYS.each do |name_key|
-        if name_key[0] != 'tags' && opts[name_key[0].to_sym]
-          value = remove_pipes(opts[name_key[0].to_sym])
-          event_string_data << "|#{name_key[1]}:#{value}"
+      OPTS_KEYS.each do |key, shorthand_key|
+        if key != :tags && opts[key]
+          value = remove_pipes(opts[key])
+          event_string_data << "|#{shorthand_key}:#{value}"
         end
       end
+
       # Tags are joined and added as last part to the string to be sent
       full_tags = (tags + (opts[:tags] || [])).map {|tag| escape_tag_content(tag) }
       unless full_tags.empty?
-        event_string_data << "|##{full_tags.join(',')}"
+        event_string_data << "|##{full_tags.join(COMMA)}"
       end
 
-      raise "Event #{title} payload is too big (more that 8KB), event discarded" if event_string_data.length > 8 * 1024
+      raise "Event #{title} payload is too big (more that 8KB), event discarded" if event_string_data.length > 8192 # 8 * 1024 = 8192
       return event_string_data
     end
 
     private
 
+    NEW_LINE = "\n".freeze
+    ESC_NEW_LINE = "\\n".freeze
+    COMMA = ",".freeze
+    BLANK = "".freeze
+    PIPE = "|".freeze
+    DOT = ".".freeze
+    DOUBLE_COLON = "::".freeze
+    UNDERSCORE = "_".freeze
+
+    private_constant :NEW_LINE, :ESC_NEW_LINE, :COMMA, :BLANK, :PIPE, :DOT,
+      :DOUBLE_COLON, :UNDERSCORE
+
     def escape_event_content(msg)
-      msg.gsub "\n", "\\n"
+      msg.gsub NEW_LINE, ESC_NEW_LINE
     end
 
     def escape_tag_content(tag)
-      remove_pipes(tag).gsub ",", ""
+      remove_pipes(tag).gsub COMMA, BLANK
     end
 
     def remove_pipes(msg)
-      msg.gsub "|", ""
+      msg.gsub PIPE, BLANK
     end
 
     def escape_service_check_message(msg)
-      msg.gsub('m:', 'm\:').gsub "\n", "\\n"
+      escape_event_content(msg).gsub('m:'.freeze, 'm\:'.freeze)
     end
 
     def time_since(stat, start, opts)
@@ -345,10 +360,10 @@ def send_stats(stat, delta, type, opts={})
       sample_rate = opts[:sample_rate] || 1
       if sample_rate == 1 or rand < sample_rate
         # Replace Ruby module scoping with '.' and reserved chars (: | @) with underscores.
-        stat = stat.to_s.gsub('::', '.').tr(':|@', '_')
+        stat = stat.to_s.gsub(DOUBLE_COLON, DOT).tr(':|@'.freeze, UNDERSCORE)
         rate = "|@#{sample_rate}" unless sample_rate == 1
         ts = (tags || []) + (opts[:tags] || []).map {|tag| escape_tag_content(tag)}
-        tags = "|##{ts.join(",")}" unless ts.empty?
+        tags = "|##{ts.join(COMMA)}" unless ts.empty?
         send_stat "#{@prefix}#{stat}:#{delta}|#{type}#{rate}#{tags}"
       end
     end
@@ -361,7 +376,7 @@ def send_to_buffer(message)
     end
 
     def flush_buffer()
-      send_to_socket(@buffer.join("\n"))
+      send_to_socket(@buffer.join(NEW_LINE))
       @buffer = Array.new
     end