From 7f344fcc15e5891ba70375e8508d1540372bd69b Mon Sep 17 00:00:00 2001
From: Donal McBreen <donal@basecamp.com>
Date: Tue, 9 Jan 2024 15:05:12 +0000
Subject: [PATCH] Expire records on a custom queue

Add `expiry_queue` to the cache config. It can be used to specify a
custom queue for SolidCache::ExpiryJob.
---
 README.md                         |  1 +
 lib/solid_cache/cluster/expiry.rb |  7 +++++--
 test/unit/expiry_test.rb          | 28 ++++++++++++++++++++++------
 3 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/README.md b/README.md
index dddea76..6411ba2 100644
--- a/README.md
+++ b/README.md
@@ -80,6 +80,7 @@ Solid Cache supports these options in addition to the standard `ActiveSupport::C
 - `error_handler` - a Proc to call to handle any `ActiveRecord::ActiveRecordError`s that are raises (default: log errors as warnings)
 - `expiry_batch_size` - the batch size to use when deleting old records (default: `100`)
 - `expiry_method` - what expiry method to use `thread` or `job` (default: `thread`)
+- `expiry_queue` - which queue to add expiry jobs to (default: `default`)
 - `max_age` - the maximum age of entries in the cache (default: `2.weeks.to_i`). Can be set to `nil`, but this is not recommended unless using `max_entries` to limit the size of the cache.
 - `max_entries` - the maximum number of entries allowed in the cache (default: `nil`, meaning no limit)
 - `cluster` - a Hash of options for the cache database cluster, e.g `{ shards: [:database1, :database2, :database3] }`
diff --git a/lib/solid_cache/cluster/expiry.rb b/lib/solid_cache/cluster/expiry.rb
index 8e5b9b9..ca2b01d 100644
--- a/lib/solid_cache/cluster/expiry.rb
+++ b/lib/solid_cache/cluster/expiry.rb
@@ -9,12 +9,13 @@ module Expiry
       # This ensures there is downward pressure on the cache size while there is valid data to delete
       EXPIRY_MULTIPLIER = 1.25
 
-      attr_reader :expiry_batch_size, :expiry_method, :expire_every, :max_age, :max_entries
+      attr_reader :expiry_batch_size, :expiry_method, :expiry_queue, :expire_every, :max_age, :max_entries
 
       def initialize(options = {})
         super(options)
         @expiry_batch_size = options.fetch(:expiry_batch_size, 100)
         @expiry_method = options.fetch(:expiry_method, :thread)
+        @expiry_queue = options.fetch(:expiry_queue, :default)
         @expire_every = [ (expiry_batch_size / EXPIRY_MULTIPLIER).floor, 1 ].max
         @max_age = options.fetch(:max_age, 2.weeks.to_i)
         @max_entries = options.fetch(:max_entries, nil)
@@ -29,7 +30,9 @@ def track_writes(count)
       private
         def expire_later
           if expiry_method == :job
-            ExpiryJob.perform_later(expiry_batch_size, shard: Entry.current_shard, max_age: max_age, max_entries: max_entries)
+            ExpiryJob
+              .set(queue: expiry_queue)
+              .perform_later(expiry_batch_size, shard: Entry.current_shard, max_age: max_age, max_entries: max_entries)
           else
             async { Entry.expire(expiry_batch_size, max_age: max_age, max_entries: max_entries) }
           end
diff --git a/test/unit/expiry_test.rb b/test/unit/expiry_test.rb
index 3be9495..10bd0b8 100644
--- a/test/unit/expiry_test.rb
+++ b/test/unit/expiry_test.rb
@@ -117,10 +117,26 @@ class SolidCache::ExpiryTest < ActiveSupport::TestCase
     end
   end
 
-    private
-      def shard_keys(cache, shard)
-        namespaced_keys = 100.times.map { |i| @cache.send(:normalize_key, "key#{i}", {}) }
-        shard_keys = cache.primary_cluster.send(:connections).assign(namespaced_keys)[shard]
-        shard_keys.map { |key| key.delete_prefix("#{@namespace}:") }
-      end
+  test "expires old records with a custom queue" do
+    @cache = lookup_store(expiry_batch_size: 3, max_entries: 2, expiry_method: :job, expiry_queue: :cache_expiry)
+
+    default_shard_keys = shard_keys(@cache, :default)
+
+    assert_enqueued_jobs(2, only: SolidCache::ExpiryJob, queue: :cache_expiry) do
+      @cache.write(default_shard_keys[0], 1)
+      @cache.write(default_shard_keys[1], 2)
+      @cache.write(default_shard_keys[2], 3)
+      @cache.write(default_shard_keys[2], 4)
+    end
+
+    perform_enqueued_jobs
+    assert_equal 0, SolidCache.each_shard.sum { SolidCache::Entry.count }
+  end
+
+  private
+    def shard_keys(cache, shard)
+      namespaced_keys = 100.times.map { |i| @cache.send(:normalize_key, "key#{i}", {}) }
+      shard_keys = cache.primary_cluster.send(:connections).assign(namespaced_keys)[shard]
+      shard_keys.map { |key| key.delete_prefix("#{@namespace}:") }
+    end
 end