discourse/spec/lib/cache_spec.rb
Loïc Guitaut 2a22a3b51d FIX: Treat corrupt cache as cache miss
Currently when a cache entry is corrupt, we log the event without doing
anything else. It means the cache is still corrupt, and the proper value
isn’t computed again.

Normally, it’s very rare the cache becomes corrupt, but it can happen
when upgrading Rails for example and the cache format changes. This is
normally handled automatically by Rails but since we’re using a custom
cache class, we have to do it ourselves.

This patch takes the same approach the Rails team did, when a cache
entry is corrupt, we treat it as a miss, recomputing the proper value
and caching it in the new format.
2024-06-18 14:47:33 +02:00

126 lines
2.7 KiB
Ruby

# frozen_string_literal: true
require "cache"
RSpec.describe Cache do
subject(:cache) { Cache.new }
it "supports exist?" do
cache.write("testing", 1.1)
expect(cache.exist?("testing")).to eq(true)
expect(cache.exist?(SecureRandom.hex)).to eq(false)
end
it "supports float" do
cache.write("float", 1.1)
expect(cache.read("float")).to eq(1.1)
end
it "supports fixnum" do
cache.write("num", 1)
expect(cache.read("num")).to eq(1)
end
it "supports hash" do
hash = { a: 1, b: [1, 2, 3] }
cache.write("hash", hash)
expect(cache.read("hash")).to eq(hash)
end
it "can be cleared" do
Discourse.redis.set("boo", "boo")
cache.write("hello0", "world")
cache.write("hello1", "world")
cache.clear
expect(Discourse.redis.get("boo")).to eq("boo")
expect(cache.read("hello0")).to eq(nil)
end
it "can delete correctly" do
cache.delete("key")
cache.fetch("key", expires_in: 1.minute) { "test" }
expect(cache.fetch("key")).to eq("test")
cache.delete("key")
expect(cache.fetch("key")).to eq(nil)
end
it "calls setex in redis" do
cache.delete("key")
cache.delete("bla")
key = cache.normalize_key("key")
cache.fetch("key", expires_in: 1.minute) { "bob" }
expect(Discourse.redis.ttl(key)).to be_within(2.seconds).of(1.minute)
# we always expire withing a day
cache.fetch("bla") { "hi" }
key = cache.normalize_key("bla")
expect(Discourse.redis.ttl(key)).to be_within(2.seconds).of(1.day)
end
it "can store and fetch correctly" do
cache.delete "key"
r =
cache.fetch "key" do
"bob"
end
expect(r).to eq("bob")
end
it "can fetch existing correctly" do
cache.write "key", "bill"
r =
cache.fetch "key" do
"bob"
end
expect(r).to eq("bill")
end
it "can fetch keys with pattern" do
cache.write "users:admins", "jeff"
cache.write "users:moderators", "bob"
expect(cache.keys("users:*").count).to eq(2)
end
it "can fetch namespace" do
expect(cache.namespace).to eq("_CACHE")
end
it "uses the defined expires_in" do
cache.write "foo:bar", "baz", expires_in: 3.minutes
expect(cache.redis.ttl("#{cache.namespace}:foo:bar")).to eq(180)
end
describe ".fetch" do
subject(:fetch_value) { cache.fetch("my_key") { "bob" } }
context "when the cache is corrupt" do
before do
cache.delete("my_key")
Discourse.redis.setex(cache.normalize_key("my_key"), described_class::MAX_CACHE_AGE, "")
end
it "runs and return the provided block" do
expect(fetch_value).to eq("bob")
end
it "generates a new cache entry" do
fetch_value
expect(cache.read("my_key")).to eq("bob")
end
end
end
end