Configure fail safe mechanism

README.md

@@ -241,14 +241,20 @@ Kredis::Connections.connections[:shared] = Redis.new(
 
 The above code could be added to either `config/environments/production.rb` or an initializer. Please ensure that your client private key, if used, is stored your credentials file or another secure location.
 
-### Configure how the redis client is created
+### Configuration
 
 You can configure how the redis client is created by setting `config.kredis.connector` in your `application.rb`:
 
 ```ruby
 config.kredis.connector = ->(config) { SomeRedisProxy.new(config) }
 ```
 
+The fail safe mechanism supports silently rescuing or returning a default value in the event that the Redis client returns an error (e.g. Redis is down). You can disable the default fail safe mechanism:
+
+```ruby
+config.kredis.fail_safe = false
+```
+
 By default Kredis will use `Redis.new(config)`.
 
 ## License

lib/kredis/railtie.rb

@@ -14,6 +14,7 @@ class Kredis::Railtie < ::Rails::Railtie
 
   initializer "kredis.configuration" do
     Kredis::Connections.connector = config.kredis.connector || ->(config) { Redis.new(config) }
+    Kredis::Types::Proxy.fail_safe_enabled = !!config.kredis.fail_safe
   end
 
   initializer "kredis.configurator" do

lib/kredis/types/proxy/failsafe.rb

@@ -1,26 +1,33 @@
 module Kredis::Types::Proxy::Failsafe
-  def initialize(*)
-    super
-    @fail_safe_suppressed = false
-  end
+  extend ActiveSupport::Concern
 
-  def failsafe
-    yield
-  rescue Redis::BaseError
-    raise if fail_safe_suppressed?
+  included do
+    mattr_accessor :fail_safe_enabled, default: true
   end
 
-  def suppress_failsafe_with(returning: nil)
-    old_fail_safe_suppressed, @fail_safe_suppressed = @fail_safe_suppressed, true
-    yield
-  rescue Redis::BaseError
-    returning
-  ensure
-    @fail_safe_suppressed = old_fail_safe_suppressed
+  def failsafe(returning: nil, &block)
+    if fail_safe_enabled? && !fail_safe_suppressed?
+      rescue_redis_errors_with(returning: returning, &block)
+    else
+      yield
+    end
   end
 
   private
+    def fail_safe_enabled?
+      fail_safe_enabled
+    end
+
     def fail_safe_suppressed?
       @fail_safe_suppressed
     end
+
+    def rescue_redis_errors_with(returning: nil)
+      old_fail_safe_suppressed, @fail_safe_suppressed = @fail_safe_suppressed, true
+      yield
+    rescue Redis::BaseError
+      returning
+    ensure
+      @fail_safe_suppressed = old_fail_safe_suppressed
+    end
 end

lib/kredis/types/proxying.rb

@@ -3,6 +3,8 @@
 class Kredis::Types::Proxying
   attr_accessor :proxy, :key
 
+  delegate :failsafe, to: :proxy
+
   def self.proxying(*commands)
     delegate *commands, to: :proxy
   end
@@ -13,10 +15,6 @@ def initialize(redis, key, **options)
     options.each { |key, value| send("#{key}=", value) }
   end
 
-  def failsafe(returning: nil, &block)
-    proxy.suppress_failsafe_with(returning: returning, &block)
-  end
-
   private
     delegate :type_to_string, :string_to_type, :types_to_strings, :strings_to_types, to: :Kredis
 end

test/proxy_test.rb

@@ -19,4 +19,14 @@ class ProxyTest < ActiveSupport::TestCase
     assert @proxy.set("two")
     stub_redis_down(@proxy) { assert_nil @proxy.set("two") }
   end
+
+  test "with fail safe disabled an error is raised" do
+    @proxy.fail_safe_enabled = false
+
+    stub_redis_down(@proxy) do
+      assert_raises(Redis::BaseError) { @proxy.get }
+    end
+
+    @proxy.fail_safe_enabled = true
+  end
 end