Merge pull request #14 from github/avoid-openssl

Avoid loading openssl + securerandom unless needed

lib/statsd.rb

@@ -1,7 +1,4 @@
-require 'openssl'
-require 'securerandom'
 require 'socket'
-require 'time'
 require 'zlib'
 
 # = Statsd: A Statsd client (https://github.com/etsy/statsd)
@@ -32,9 +29,6 @@ def initialize(host, port, key = nil)
   #characters that will be replaced with _ in stat names
   RESERVED_CHARS_REGEX = /[\:\|\@]/
 
-  # Digest object as a constant
-  SHA256 = OpenSSL::Digest::SHA256.new
-
   class << self
     # Set to any standard logger instance (including stdlib's Logger) to enable
     # stat logging using logger.debug
@@ -150,11 +144,22 @@ def select_host(stat)
   end
 
   def signed_payload(key, message)
+    sha256 = Statsd.setup_openssl
     payload = timestamp + nonce + message
-    signature = OpenSSL::HMAC.digest(SHA256, key, payload)
+    signature = OpenSSL::HMAC.digest(sha256, key, payload)
     signature + payload
   end
 
+  # defer loading openssl and securerandom unless needed. this shaves ~10ms off
+  # of baseline require load time for environments that don't require message signing.
+  def self.setup_openssl
+    @sha256 ||= begin
+      require 'securerandom'
+      require 'openssl'
+      OpenSSL::Digest::SHA256.new
+    end
+  end
+
   def timestamp
     [Time.now.to_i].pack("Q<")
   end