Adds chaos endpoints to Sidekiq

This allows the chaos endpoints to be invoked in Sidekiq so that this
environment can be tested for resilience.

1 files changed, 49 insertions, 0 deletions

diff --git a/lib/gitlab/chaos.rb b/lib/gitlab/chaos.rb
new file mode 100644
index 00000000000..4f47cdef971
--- /dev/null
+++ b/lib/gitlab/chaos.rb
@@ -0,0 +1,49 @@
+# frozen_string_literal: true
+
+module Gitlab
+  # Chaos methods for GitLab.
+  # See https://docs.gitlab.com/ee/development/chaos_endpoints.html for more details.
+  class Chaos
+    # leak_mem will retain the specified amount of memory and sleep.
+    # On return, the memory will be released.
+    def self.leak_mem(memory_mb, duration_s)
+      start_time = Time.now
+
+      retainer = []
+      # Add `n` 1mb chunks of memory to the retainer array
+      memory_mb.times { retainer << "x" * 1.megabyte }
+
+      duration_left = [start_time + duration_s - Time.now, 0].max
+      Kernel.sleep(duration_left)
+    end
+
+    # cpu_spin will consume all CPU on a single core for the specified duration
+    def self.cpu_spin(duration_s)
+      expected_end_time = Time.now + duration_s
+
+      rand while Time.now < expected_end_time
+    end
+
+    # db_spin will query the database in a tight loop for the specified duration
+    def self.db_spin(duration_s, interval_s)
+      expected_end_time = Time.now + duration_s
+
+      while Time.now < expected_end_time
+        ActiveRecord::Base.connection.execute("SELECT 1")
+
+        end_interval_time = Time.now + [duration_s, interval_s].min
+        rand while Time.now < end_interval_time
+      end
+    end
+
+    # sleep will sleep for the specified duration
+    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)
+    end
+  end
+end