Merge branch 'mk-chaos-quit' into 'master'

Add a chaos endpoint that signals QUIT

See merge request gitlab-org/gitlab!58755

app/controllers/chaos_controller.rb

@@ -20,7 +20,11 @@ def sleep
   end
 
   def kill
-    do_chaos :kill, Chaos::KillWorker
+    do_chaos :kill, Chaos::KillWorker, 'KILL'
+  end
+
+  def quit
+    do_chaos :kill, Chaos::KillWorker, 'QUIT'
   end
 
   def gc

app/workers/chaos/kill_worker.rb

@@ -7,8 +7,8 @@ class KillWorker # rubocop:disable Scalability/IdempotentWorker
 
     sidekiq_options retry: false
 
-    def perform
-      Gitlab::Chaos.kill
+    def perform(signal)
+      Gitlab::Chaos.kill(signal)
     end
   end
 end

changelogs/unreleased/mk-chaos-quit.yml

+---
+title: Add a chaos endpoint that signals QUIT
+merge_request: 58755
+author:
+type: changed

config/routes.rb

@@ -179,6 +179,7 @@
         get :db_spin
         get :sleep
         get :kill
+        get :quit
         post :gc
       end
     end

doc/development/chaos_endpoints.md

@@ -146,10 +146,10 @@ curl "http://localhost:3000/-/chaos/sleep?duration_s=60&token=secret"
 
 ## Kill
 
-This endpoint simulates the unexpected death of a worker process using a `kill` signal.
+This endpoint simulates the unexpected death of a worker process using the `KILL` signal.
 
-Because this endpoint uses the `KILL` signal, the worker isn't given an
-opportunity to cleanup or shutdown.
+Because this endpoint uses the `KILL` signal, the process isn't given an
+opportunity to clean up or shut down.
 
 ```plaintext
 GET /-/chaos/kill
@@ -158,13 +158,33 @@ GET /-/chaos/kill?async=true
 
 | Attribute    | Type    | Required | Description                                                            |
 | ------------ | ------- | -------- | ---------------------------------------------------------------------- |
-| `async`      | boolean | no       | Set to true to kill a Sidekiq background worker process                |
+| `async`      | boolean | no       | Set to true to signal a Sidekiq background worker process              |
 
 ```shell
 curl "http://localhost:3000/-/chaos/kill" --header 'X-Chaos-Secret: secret'
 curl "http://localhost:3000/-/chaos/kill?token=secret"
 ```
 
+## Quit
+
+This endpoint simulates the unexpected death of a worker process using the `QUIT` signal.
+Unlike `KILL`, the `QUIT` signal will also attempt to write a core dump.
+See [core(5)](https://man7.org/linux/man-pages/man5/core.5.html) for more information.
+
+```plaintext
+GET /-/chaos/quit
+GET /-/chaos/quit?async=true
+```
+
+| Attribute    | Type    | Required | Description                                                            |
+| ------------ | ------- | -------- | ---------------------------------------------------------------------- |
+| `async`      | boolean | no       | Set to true to signal a Sidekiq background worker process              |
+
+```shell
+curl "http://localhost:3000/-/chaos/quit" --header 'X-Chaos-Secret: secret'
+curl "http://localhost:3000/-/chaos/quit?token=secret"
+```
+
 ## Run garbage collector
 
 This endpoint triggers a GC run on the worker handling the request and returns its worker ID

lib/gitlab/chaos.rb

@@ -43,9 +43,9 @@ def self.sleep(duration_s)
       Kernel.sleep(duration_s)
     end
 
-    # Kill will send a SIGKILL signal to the current process
-    def self.kill
-      Process.kill("KILL", Process.pid)
+    # Kill will send the given signal to the current process.
+    def self.kill(signal)
+      Process.kill(signal, Process.pid)
     end
 
     def self.run_gc

spec/controllers/chaos_controller_spec.rb

@@ -109,7 +109,7 @@
 
   describe '#kill' do
     it 'calls synchronously' do
-      expect(Gitlab::Chaos).to receive(:kill).with(no_args)
+      expect(Gitlab::Chaos).to receive(:kill).with('KILL')
 
       get :kill
 
@@ -117,7 +117,7 @@
     end
 
     it 'calls asynchronously' do
-      expect(Chaos::KillWorker).to receive(:perform_async).with(no_args)
+      expect(Chaos::KillWorker).to receive(:perform_async).with('KILL')
 
       get :kill, params: { async: 1 }
 
@@ -125,6 +125,24 @@
     end
   end
 
+  describe '#quit' do
+    it 'calls synchronously' do
+      expect(Gitlab::Chaos).to receive(:kill).with('QUIT')
+
+      get :quit
+
+      expect(response).to have_gitlab_http_status(:ok)
+    end
+
+    it 'calls asynchronously' do
+      expect(Chaos::KillWorker).to receive(:perform_async).with('QUIT')
+
+      get :quit, params: { async: 1 }
+
+      expect(response).to have_gitlab_http_status(:ok)
+    end
+  end
+
   describe '#gc' do
     let(:gc_stat) { GC.stat.stringify_keys }