Merge pull request #511 from zendesk/dasch/lazy-load-compressors

Lazy load compressors

Author: dasch

lib/kafka/compression.rb

@@ -21,9 +21,13 @@ def self.codecs
     end
 
     def self.find_codec(name)
-      CODECS.fetch(name) do
+      codec = CODECS.fetch(name) do
         raise "Unknown compression codec #{name}"
       end
+
+      codec.load
+
+      codec
     end
 
     def self.find_codec_by_id(codec_id)

lib/kafka/gzip_codec.rb

@@ -1,13 +1,13 @@
 module Kafka
   class GzipCodec
-    def initialize
-      require "zlib"
-    end
-
     def codec_id
       1
     end
 
+    def load
+      require "zlib"
+    end
+
     def compress(data)
       buffer = StringIO.new
       buffer.set_encoding(Encoding::BINARY)

lib/kafka/lz4_codec.rb

@@ -1,15 +1,15 @@
 module Kafka
   class LZ4Codec
-    def initialize
+    def codec_id
+      3
+    end
+
+    def load
       require "extlz4"
     rescue LoadError
       raise LoadError, "using lz4 compression requires adding a dependency on the `extlz4` gem to your Gemfile."
     end
 
-    def codec_id
-      3
-    end
-
     def compress(data)
       LZ4.encode(data)
     end

lib/kafka/snappy_codec.rb

@@ -1,16 +1,16 @@
 module Kafka
   class SnappyCodec
-    def initialize
+    def codec_id
+      2
+    end
+
+    def load
       require "snappy"
     rescue LoadError
       raise LoadError,
         "Using snappy compression requires adding a dependency on the `snappy` gem to your Gemfile."
     end
 
-    def codec_id
-      2
-    end
-
     def compress(data)
       Snappy.deflate(data)
     end