mstruve · November 16, 2018 19:48 · Nov 16, 2018
diff --git a/redis.rb b/redis.rb
@@ -0,0 +1,28 @@
+if ENV['REDIS_ACCESS_MODE'] == 'readonly'
+  class Redis
+    class Client
+      WRITE_COMMANDS = ::Rails.cache.data.command.map { |a| a[0] if a[2].include?('write') }.compact.to_set.freeze
+
+      def process(commands)
+        if commands.flatten.any? { |c| WRITE_COMMANDS.include?(c.to_s) }
+          raise NotImplementedError, "REDIS_ACCESS_MODE is set to 'readonly', disallowing writes"
+        end
+
+        logging(commands) do
+          ensure_connected do
+            commands.each do |command|
+              if command_map[command.first]
+                command = command.dup
+                command[0] = command_map[command.first]
+              end
+
+              write(command)
+            end
+
+            yield if block_given?
+          end
+        end
+      end
+    end
+  end
+end