Bring Gitlab::ShardHealthCache to CE

It already existed in EE in the Geo namespace. This change brings it
to CE.

1 files changed, 52 insertions, 0 deletions

diff --git a/spec/lib/gitlab/shard_health_cache_spec.rb b/spec/lib/gitlab/shard_health_cache_spec.rb
new file mode 100644
index 00000000000..e1a69261939
--- /dev/null
+++ b/spec/lib/gitlab/shard_health_cache_spec.rb
@@ -0,0 +1,52 @@
+require 'spec_helper'
+
+describe Gitlab::ShardHealthCache, :clean_gitlab_redis_cache do
+  let(:shards) { %w(foo bar) }
+
+  before do
+    described_class.update(shards)
+  end
+
+  describe '.clear' do
+    it 'leaves no shards around' do
+      described_class.clear
+
+      expect(described_class.healthy_shard_count).to eq(0)
+    end
+  end
+
+  describe '.update' do
+    it 'returns the healthy shards' do
+      expect(described_class.cached_healthy_shards).to match_array(shards)
+    end
+
+    it 'replaces the existing set' do
+      new_set = %w(test me more)
+      described_class.update(new_set)
+
+      expect(described_class.cached_healthy_shards).to match_array(new_set)
+    end
+  end
+
+  describe '.healthy_shard_count' do
+    it 'returns the healthy shard count' do
+      expect(described_class.healthy_shard_count).to eq(2)
+    end
+
+    it 'returns 0 if no shards are available' do
+      described_class.update([])
+
+      expect(described_class.healthy_shard_count).to eq(0)
+    end
+  end
+
+  describe '.healthy_shard?' do
+    it 'returns true for a healthy shard' do
+      expect(described_class.healthy_shard?('foo')).to be_truthy
+    end
+
+    it 'returns false for an unknown shard' do
+      expect(described_class.healthy_shard?('unknown')).to be_falsey
+    end
+  end
+end