Add :expires_in option support for RedisCacheStore increment/decrement method.

3 files changed, 57 insertions, 2 deletions

diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 100d57aa16..8031d351a9 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -131,5 +131,16 @@
 
     *Eileen M. Uchitelle*, *Aaron Patterson*
 
+*   RedisCacheStore: Support expiring counters.
+    Pass `expires_in: [seconds]` to `#increment` and `#decrement` options
+    to set the Redis EXPIRE if the counter doesn't exist.
+    If the counter exists, Redis doesn't extend its expiry when it's exist.
+
+    ```
+    Rails.cache.increment("my_counter", 1, expires_in: 2.minutes)
+    ```
+
+    *Jason Lee*
+
 
 Please check [5-2-stable](https://github.com/rails/rails/blob/5-2-stable/activesupport/CHANGELOG.md) for previous changes.
diff --git a/activesupport/lib/active_support/cache/redis_cache_store.rb b/activesupport/lib/active_support/cache/redis_cache_store.rb
index 11c574258f..95f8f639e8 100644
--- a/activesupport/lib/active_support/cache/redis_cache_store.rb
+++ b/activesupport/lib/active_support/cache/redis_cache_store.rb
@@ -256,9 +256,19 @@ module ActiveSupport
       #
       # Failsafe: Raises errors.
       def increment(name, amount = 1, options = nil)
+        options = merged_options(options)
+        key = normalize_key(name, options)
+        expires_in = options[:expires_in].to_i
+
         instrument :increment, name, amount: amount do
           failsafe :increment do
-            redis.with { |c| c.incrby normalize_key(name, options), amount }
+            redis.with do |c|
+              val = c.incrby key, amount
+              if expires_in > 0 && c.ttl(key) == -2
+                c.expire key, expires_in
+              end
+              val
+            end
           end
         end
       end
@@ -272,9 +282,19 @@ module ActiveSupport
       #
       # Failsafe: Raises errors.
       def decrement(name, amount = 1, options = nil)
+        options = merged_options(options)
+        key = normalize_key(name, options)
+        expires_in = options[:expires_in].to_i
+
         instrument :decrement, name, amount: amount do
           failsafe :decrement do
-            redis.with { |c| c.decrby normalize_key(name, options), amount }
+            redis.with do |c|
+              val = c.decrby key, amount
+              if expires_in > 0 && c.ttl(key) == -2
+                c.expire key, expires_in
+              end
+              val
+            end
           end
         end
       end
diff --git a/activesupport/test/cache/stores/redis_cache_store_test.rb b/activesupport/test/cache/stores/redis_cache_store_test.rb
index 24c4c5c481..a2165e1978 100644
--- a/activesupport/test/cache/stores/redis_cache_store_test.rb
+++ b/activesupport/test/cache/stores/redis_cache_store_test.rb
@@ -141,6 +141,30 @@ module ActiveSupport::Cache::RedisCacheStoreTests
         end
       end
     end
+
+    def test_increment_expires_in
+      assert_called_with @cache.redis, :incrby, [ "#{@namespace}:foo", 1 ] do
+        assert_called_with @cache.redis, :expire, [ "#{@namespace}:foo", 60 ] do
+          @cache.increment("foo", 1, expires_in: 60)
+        end
+      end
+
+      assert_not_called @cache.redis, :expire do
+        @cache.decrement("foo", 1, expires_in: 60)
+      end
+    end
+
+    def test_decrement_expires_in
+      assert_called_with @cache.redis, :decrby, [ "#{@namespace}:foo", 1 ] do
+        assert_called_with @cache.redis, :expire, [ "#{@namespace}:foo", 60 ] do
+          @cache.decrement("foo", 1, expires_in: 60)
+        end
+      end
+
+      assert_not_called @cache.redis, :expire do
+        @cache.decrement("foo", 1, expires_in: 60)
+      end
+    end
   end
 
   class ConnectionPoolBehaviourTest < StoreTest