DEV: Add expires flag to enable_readonly (#29033)

... to control whether readonly mode expires or not.

lib/discourse.rb

@@ -675,16 +675,20 @@ module Discourse
     PG_FORCE_READONLY_MODE_KEY,
   ]
 
-  def self.enable_readonly_mode(key = READONLY_MODE_KEY)
+  def self.enable_readonly_mode(key = READONLY_MODE_KEY, expires: nil)
     if key == PG_READONLY_MODE_KEY || key == PG_FORCE_READONLY_MODE_KEY
       Sidekiq.pause!("pg_failover") if !Sidekiq.paused?
     end
 
-    if [USER_READONLY_MODE_KEY, PG_FORCE_READONLY_MODE_KEY, STAFF_WRITES_ONLY_MODE_KEY].include?(
-         key,
-       )
-      Discourse.redis.set(key, 1)
-    else
+    if expires.nil?
+      expires = [
+        USER_READONLY_MODE_KEY,
+        PG_FORCE_READONLY_MODE_KEY,
+        STAFF_WRITES_ONLY_MODE_KEY,
+      ].exclude?(key)
+    end
+
+    if expires
       ttl =
         case key
         when PG_READONLY_MODE_KEY
@@ -695,6 +699,8 @@ module Discourse
 
       Discourse.redis.setex(key, ttl, 1)
       keep_readonly_mode(key, ttl: ttl) if !Rails.env.test?
+    else
+      Discourse.redis.set(key, 1)
     end
 
     MessageBus.publish(readonly_channel, true)

spec/lib/discourse_spec.rb

@@ -253,6 +253,16 @@ RSpec.describe Discourse do
     end
 
     describe ".enable_readonly_mode" do
+      it "doesn't expire when expires is false" do
+        Discourse.enable_readonly_mode(user_readonly_mode_key, expires: false)
+        expect(Discourse.redis.ttl(user_readonly_mode_key)).to eq(-1)
+      end
+
+      it "expires when expires is true" do
+        Discourse.enable_readonly_mode(user_readonly_mode_key, expires: true)
+        expect(Discourse.redis.ttl(user_readonly_mode_key)).not_to eq(-1)
+      end
+
       it "adds a key in redis and publish a message through the message bus" do
         expect(Discourse.redis.get(readonly_mode_key)).to eq(nil)
       end