discourse/spec/lib/discourse_redis_spec.rb

# frozen_string_literal: true

RSpec.describe DiscourseRedis do
  it "ignore_readonly returns nil from a pure exception" do
    result = DiscourseRedis.ignore_readonly { raise Redis::CommandError.new("READONLY") }
    expect(result).to eq(nil)
  end

  describe 'redis commands' do
    let(:raw_redis) { Redis.new(DiscourseRedis.config) }

    before do
      raw_redis.flushdb
    end

    after do
      raw_redis.flushdb
    end

    describe 'pipelined / multi' do
      let(:redis) { DiscourseRedis.new }

      it 'should support multi commands' do
        val = redis.multi do |transaction|
          transaction.set 'foo', 'bar'
          transaction.set 'bar', 'foo'
          transaction.get 'bar'
        end

        expect(raw_redis.get('foo')).to eq(nil)
        expect(raw_redis.get('bar')).to eq(nil)
        expect(redis.get('foo')).to eq('bar')
        expect(redis.get('bar')).to eq('foo')

        expect(val).to eq(["OK", "OK", "foo"])
      end

      it 'should support pipelined commands' do
        set, incr = nil
        val = redis.pipelined do |pipeline|
          set = pipeline.set "foo", "baz"
          incr = pipeline.incr "baz"
        end

        expect(val).to eq(["OK", 1])

        expect(set.value).to eq("OK")
        expect(incr.value).to eq(1)

        expect(raw_redis.get('foo')).to eq(nil)
        expect(raw_redis.get('baz')).to eq(nil)

        expect(redis.get('foo')).to eq("baz")
        expect(redis.get('baz')).to eq("1")
      end

      it 'should noop pipelined commands against a readonly redis' do
        redis.without_namespace
          .expects(:pipelined)
          .raises(Redis::CommandError.new("READONLY"))

        set, incr = nil

        val = redis.pipelined do |pipeline|
          set = pipeline.set "foo", "baz"
          incr = pipeline.incr "baz"
        end

        expect(val).to eq(nil)
        expect(redis.get('foo')).to eq(nil)
        expect(redis.get('baz')).to eq(nil)
      end

      it 'should noop multi commands against a readonly redis' do
        redis.without_namespace
          .expects(:multi)
          .raises(Redis::CommandError.new("READONLY"))

        val = redis.multi do |transaction|
          transaction.set 'foo', 'bar'
          transaction.set 'bar', 'foo'
          transaction.get 'bar'
        end

        expect(val).to eq(nil)
        expect(redis.get('foo')).to eq(nil)
        expect(redis.get('bar')).to eq(nil)
      end
    end

    describe 'when namespace is enabled' do
      let(:redis) { DiscourseRedis.new }

      it 'should append namespace to the keys' do
        raw_redis.set('default:key', 1)
        raw_redis.set('test:key2', 1)
        raw_redis.set('default:key3', 1)

        expect(redis.keys).to include('key')
        expect(redis.keys).to_not include('key2')
        expect(redis.scan_each.to_a).to contain_exactly('key', 'key3')

        redis.del('key', 'key3')

        expect(raw_redis.get('default:key')).to eq(nil)
        expect(raw_redis.get('default:key3')).to eq(nil)

        expect(redis.scan_each.to_a).to eq([])

        raw_redis.set('default:key1', '1')
        raw_redis.set('default:key2', '2')

        expect(redis.mget('key1', 'key2')).to eq(['1', '2'])
        expect(redis.scan_each.to_a).to contain_exactly('key1', 'key2')
      end
    end

    describe 'when namespace is disabled' do
      let(:redis) { DiscourseRedis.new(nil, namespace: false) }

      it 'should not append any namespace to the keys' do
        raw_redis.set('default:key', 1)
        raw_redis.set('test:key2', 1)

        expect(redis.keys).to include('default:key', 'test:key2')

        raw_redis.set('key1', '1')
        raw_redis.set('key2', '2')

        expect(redis.mget('key1', 'key2')).to eq(['1', '2'])

        redis.del('key1', 'key2')

        expect(redis.mget('key1', 'key2')).to eq([nil, nil])
      end

      it 'should noop a readonly redis' do
        expect(Discourse.recently_readonly?).to eq(false)

        redis.without_namespace
          .expects(:set)
          .raises(Redis::CommandError.new("READONLY"))

        redis.set('key', 1)

        expect(Discourse.recently_readonly?).to eq(true)
      end
    end

    describe "#eval" do
      it "keys and arvg are passed correcty" do
        keys = ["key1", "key2"]
        argv = ["arg1", "arg2"]

        expect(Discourse.redis.eval(
          "return { KEYS, ARGV };",
          keys: keys,
          argv: argv,
        )).to eq([keys, argv])

        expect(Discourse.redis.eval(
          "return { KEYS, ARGV };",
          keys,
          argv: argv,
        )).to eq([keys, argv])

        expect(Discourse.redis.eval(
          "return { KEYS, ARGV };",
          keys,
          argv,
        )).to eq([keys, argv])
      end
    end

    describe "#evalsha" do
      it "keys and arvg are passed correcty" do
        keys = ["key1", "key2"]
        argv = ["arg1", "arg2"]

        script = "return { KEYS, ARGV };"
        Discourse.redis.script(:load, script)
        sha = Digest::SHA1.hexdigest(script)
        expect(Discourse.redis.evalsha(
          sha,
          keys: keys,
          argv: argv,
        )).to eq([keys, argv])

        expect(Discourse.redis.evalsha(
          sha,
          keys,
          argv: argv,
        )).to eq([keys, argv])

        expect(Discourse.redis.evalsha(
          sha,
          keys,
          argv,
        )).to eq([keys, argv])
      end
    end
  end

  describe DiscourseRedis::EvalHelper do
    it "works" do
      helper = DiscourseRedis::EvalHelper.new <<~LUA
        return 'hello world'
      LUA
      expect(helper.eval(Discourse.redis)).to eq('hello world')
    end

    it "works with arguments" do
      helper = DiscourseRedis::EvalHelper.new <<~LUA
        return ARGV[1]..ARGV[2]..KEYS[1]..KEYS[2]
      LUA
      expect(helper.eval(Discourse.redis, ['key1', 'key2'], ['arg1', 'arg2'])).to eq("arg1arg2key1key2")
    end

    it "works with arguments" do
      helper = DiscourseRedis::EvalHelper.new <<~LUA
        return ARGV[1]..ARGV[2]..KEYS[1]..KEYS[2]
      LUA
      expect(helper.eval(Discourse.redis, ['key1', 'key2'], ['arg1', 'arg2'])).to eq("arg1arg2key1key2")
    end

    it "uses evalsha correctly" do
      redis_proxy = Class.new do
        attr_reader :calls
        def method_missing(meth, *args, **kwargs, &block)
          @calls ||= []
          @calls.push(meth)
          Discourse.redis.public_send(meth, *args, **kwargs, &block)
        end
      end.new

      Discourse.redis.call("SCRIPT", "FLUSH", "SYNC")

      helper = DiscourseRedis::EvalHelper.new <<~LUA
        return 'hello world'
      LUA
      expect(helper.eval(redis_proxy)).to eq("hello world")
      expect(helper.eval(redis_proxy)).to eq("hello world")
      expect(helper.eval(redis_proxy)).to eq("hello world")

      expect(redis_proxy.calls).to eq([:evalsha, :eval, :evalsha, :evalsha])
    end
  end

  describe ".new_redis_store" do
    let(:cache) { Cache.new(namespace: 'foo') }
    let(:store) { DiscourseRedis.new_redis_store }

    before do
      cache.redis.del("key")
      store.delete("key")
    end

    it "can store stuff" do
      store.fetch("key") do
        "key in store"
      end

      r = store.read("key")

      expect(r).to eq("key in store")
    end

    it "doesn't collide with our Cache" do
      store.fetch("key") do
        "key in store"
      end

      cache.fetch("key") do
        "key in cache"
      end

      r = store.read("key")

      expect(r).to eq("key in store")
    end

    it "can be cleared without clearing our cache" do
      cache.clear
      store.clear

      store.fetch("key") do
        "key in store"
      end

      cache.fetch("key") do
        "key in cache"
      end

      store.clear

      expect(store.read("key")).to eq(nil)
      expect(cache.fetch("key")).to eq("key in cache")
    end
  end
end