Add bypass option

Allows to bypass caching, locking or both.

Author: m-o-e

README.md

@@ -150,6 +150,26 @@ Check locks with
 LockAndCache.locked? :stock_price, company: 'MSFT', date: '2015-05-05'
 ```
 
+Caching, locking or both can be bypassed
+
+```ruby
+LockAndCache.lock_and_cache(:stock_price, {company: 'MSFT', date: '2015-05-05'}, expires: 10, nil_expires: 1, bypass: :cache) do
+  # ignore any cached value, get yer stock quote
+end
+```
+
+```ruby
+LockAndCache.lock_and_cache(:stock_price, {company: 'MSFT', date: '2015-05-05'}, expires: 10, nil_expires: 1, bypass: :lock) do
+  # return cached value if it exists, otherwise get yet stock quote *without* acquiring lock
+end
+```
+
+```ruby
+LockAndCache.lock_and_cache(:stock_price, {company: 'MSFT', date: '2015-05-05'}, expires: 10, nil_expires: 1, bypass: :both) do
+  # get yer stock quote without caching or locking
+end
+```
+
 #### Context mode
 
 "Context mode" simply adds the class name, method name, and context key (the results of `#id` or `#lock_and_cache_key`) of the caller to the cache key.
@@ -234,6 +254,6 @@ You can expire nil values with a different timeout (`nil_expires`) than other va
 4. Push to the branch (`git push origin my-new-feature`)
 5. Create a new Pull Request
 
-# Copyright 
+# Copyright
 
 Copyright 2015 Seamus Abshere

lib/lock_and_cache/action.rb

@@ -24,6 +24,11 @@ def nil_expires
       @nil_expires = options.has_key?('nil_expires') ? options['nil_expires'].to_f.round : nil
     end
 
+    def bypass
+      return @bypass if defined?(@bypass)
+      @bypass = options.has_key?('bypass') ? options['bypass'] : nil
+    end
+
     def digest
       @digest ||= key.digest
     end
@@ -55,21 +60,24 @@ def perform
       raise "heartbeat_expires must be >= 2 seconds" unless heartbeat_expires >= 2
       heartbeat_frequency = (heartbeat_expires / 2).ceil
       LockAndCache.logger.debug { "[lock_and_cache] A1 #{key.debug} #{Base64.encode64(digest).strip} #{Digest::SHA1.hexdigest digest}" }
-      if cache_storage.exists(digest) and (existing = cache_storage.get(digest)).is_a?(String)
+      if ![:cache, :both].include?(bypass) and cache_storage.exists(digest) and (existing = cache_storage.get(digest)).is_a?(String)
         return load_existing(existing)
       end
       LockAndCache.logger.debug { "[lock_and_cache] B1 #{key.debug} #{Base64.encode64(digest).strip} #{Digest::SHA1.hexdigest digest}" }
       retval = nil
       lock_secret = SecureRandom.hex 16
       acquired = false
       begin
-        Timeout.timeout(max_lock_wait, TimeoutWaitingForLock) do
-          until lock_storage.set(lock_digest, lock_secret, nx: true, ex: heartbeat_expires)
-            LockAndCache.logger.debug { "[lock_and_cache] C1 #{key.debug} #{Base64.encode64(digest).strip} #{Digest::SHA1.hexdigest digest}" }
-            sleep rand
+        unless [:lock, :both].include?(bypass)
+          Timeout.timeout(max_lock_wait, TimeoutWaitingForLock) do
+            until lock_storage.set(lock_digest, lock_secret, nx: true, ex: heartbeat_expires)
+              LockAndCache.logger.debug { "[lock_and_cache] C1 #{key.debug} #{Base64.encode64(digest).strip} #{Digest::SHA1.hexdigest digest}" }
+              sleep rand
+            end
+            acquired = true
           end
-          acquired = true
         end
+        return blk.call if [:cache, :both].include?(bypass)
         LockAndCache.logger.debug { "[lock_and_cache] D1 #{key.debug} #{Base64.encode64(digest).strip} #{Digest::SHA1.hexdigest digest}" }
         if cache_storage.exists(digest) and (existing = cache_storage.get(digest)).is_a?(String)
           LockAndCache.logger.debug { "[lock_and_cache] E1 #{key.debug} #{Base64.encode64(digest).strip} #{Digest::SHA1.hexdigest digest}" }

spec/lock_and_cache_spec.rb

@@ -343,6 +343,27 @@ def lock_and_cache_key
       expect(LockAndCache.lock_and_cache('hello') { raise(Exception.new("stop")) }).to eq(:red)
     end
 
+    it 'doesn\'t break when bypass has an unknown value' do
+      expect(LockAndCache.lock_and_cache('hello', bypass: nil) { :red }).to eq(:red)
+      expect(LockAndCache.lock_and_cache('hello', bypass: :foo) { raise(Exception.new("stop")) }).to eq(:red)
+    end
+
+    it 'doesn\'t cache when bypass == :cache' do
+      count = 0
+      expect(LockAndCache.lock_and_cache('hello') { count += 1 }).to eq(1)
+      expect(count).to eq(1)
+      expect(LockAndCache.lock_and_cache('hello', bypass: :cache) { count += 1 }).to eq(2)
+      expect(count).to eq(2)
+    end
+
+    it 'doesn\'t cache when bypass == :both' do
+      count = 0
+      expect(LockAndCache.lock_and_cache('hello') { count += 1 }).to eq(1)
+      expect(count).to eq(1)
+      expect(LockAndCache.lock_and_cache('hello', bypass: :both) { count += 1 }).to eq(2)
+      expect(count).to eq(2)
+    end
+
     it 'caches errors (briefly)' do
       count = 0
       expect {
@@ -434,7 +455,7 @@ def lock_and_cache_key
       expect(LockAndCache.lock_and_cache(['hello', 1, { target: 'world' }]) { count += 1 }).to eq(1)
       expect(count).to eq(1)
     end
-    
+
     it 'treats a single hash arg as a cache key (not as options)' do
       count = 0
       LockAndCache.lock_and_cache(hello: 'world', expires: 100) { count += 1 }