gitlab-org--gitlab-foss/lib/gitlab/chaos.rb

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# 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)
return unless Gitlab::Metrics::System.thread_cpu_time
expected_end_time = Gitlab::Metrics::System.thread_cpu_time + duration_s
rand while Gitlab::Metrics::System.thread_cpu_time < 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
def self.run_gc
# Tenure any live objects from young-gen to old-gen
4.times { GC.start(full_mark: false) }
# Run a full mark-and-sweep collection
GC.start
GC.stat
end
end
end