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# frozen_string_literal: true
require 'sidekiq/util'
require 'sidekiq/fetch'
require 'sidekiq/job_logger'
require 'sidekiq/job_retry'
require 'thread'
module Sidekiq
##
# The Processor is a standalone thread which:
#
# 1. fetches a job from Redis
# 2. executes the job
# a. instantiate the Worker
# b. run the middleware chain
# c. call #perform
#
# A Processor can exit due to shutdown (processor_stopped)
# or due to an error during job execution (processor_died)
#
# If an error occurs in the job execution, the
# Processor calls the Manager to create a new one
# to replace itself and exits.
#
class Processor
include Util
attr_reader :thread
attr_reader :job
def initialize(mgr)
@mgr = mgr
@down = false
@done = false
@job = nil
@thread = nil
@strategy = (mgr.options[:fetch] || Sidekiq::BasicFetch).new(mgr.options)
@reloader = Sidekiq.options[:reloader]
@logging = (mgr.options[:job_logger] || Sidekiq::JobLogger).new
@retrier = Sidekiq::JobRetry.new
end
def terminate(wait=false)
@done = true
return if !@thread
@thread.value if wait
end
def kill(wait=false)
@done = true
return if !@thread
# unlike the other actors, terminate does not wait
# for the thread to finish because we don't know how
# long the job will take to finish. Instead we
# provide a `kill` method to call after the shutdown
# timeout passes.
@thread.raise ::Sidekiq::Shutdown
@thread.value if wait
end
def start
@thread ||= safe_thread("processor", &method(:run))
end
private unless $TESTING
def run
begin
while !@done
process_one
end
@mgr.processor_stopped(self)
rescue Sidekiq::Shutdown
@mgr.processor_stopped(self)
rescue Exception => ex
@mgr.processor_died(self, ex)
end
end
def process_one
@job = fetch
process(@job) if @job
@job = nil
end
def get_one
begin
work = @strategy.retrieve_work
(logger.info { "Redis is online, #{Time.now - @down} sec downtime" }; @down = nil) if @down
work
rescue Sidekiq::Shutdown
rescue => ex
handle_fetch_exception(ex)
end
end
def fetch
j = get_one
if j && @done
j.requeue
nil
else
j
end
end
def handle_fetch_exception(ex)
if !@down
@down = Time.now
logger.error("Error fetching job: #{ex}")
handle_exception(ex)
end
sleep(1)
nil
end
def dispatch(job_hash, queue)
# since middleware can mutate the job hash
# we clone here so we report the original
# job structure to the Web UI
pristine = cloned(job_hash)
Sidekiq::Logging.with_job_hash_context(job_hash) do
@retrier.global(pristine, queue) do
@logging.call(job_hash, queue) do
stats(pristine, queue) do
# Rails 5 requires a Reloader to wrap code execution. In order to
# constantize the worker and instantiate an instance, we have to call
# the Reloader. It handles code loading, db connection management, etc.
# Effectively this block denotes a "unit of work" to Rails.
@reloader.call do
klass = constantize(job_hash['class'])
worker = klass.new
worker.jid = job_hash['jid']
@retrier.local(worker, pristine, queue) do
yield worker
end
end
end
end
end
end
end
def process(work)
jobstr = work.job
queue = work.queue_name
ack = false
begin
# Treat malformed JSON as a special case: job goes straight to the morgue.
job_hash = nil
begin
job_hash = Sidekiq.load_json(jobstr)
rescue => ex
handle_exception(ex, { :context => "Invalid JSON for job", :jobstr => jobstr })
# we can't notify because the job isn't a valid hash payload.
DeadSet.new.kill(jobstr, notify_failure: false)
ack = true
raise
end
ack = true
dispatch(job_hash, queue) do |worker|
Sidekiq.server_middleware.invoke(worker, job_hash, queue) do
execute_job(worker, cloned(job_hash['args']))
end
end
rescue Sidekiq::Shutdown
# Had to force kill this job because it didn't finish
# within the timeout. Don't acknowledge the work since
# we didn't properly finish it.
ack = false
rescue Exception => ex
e = ex.is_a?(::Sidekiq::JobRetry::Skip) && ex.cause ? ex.cause : ex
handle_exception(e, { :context => "Job raised exception", :job => job_hash, :jobstr => jobstr })
raise e
ensure
work.acknowledge if ack
end
end
def execute_job(worker, cloned_args)
worker.perform(*cloned_args)
end
# Ruby doesn't provide atomic counters out of the box so we'll
# implement something simple ourselves.
# https://bugs.ruby-lang.org/issues/14706
class Counter
def initialize
@value = 0
@lock = Mutex.new
end
def incr(amount=1)
@lock.synchronize { @value = @value + amount }
end
def reset
@lock.synchronize { val = @value; @value = 0; val }
end
end
PROCESSED = Counter.new
FAILURE = Counter.new
# This is mutable global state but because each thread is storing
# its own unique key/value, there's no thread-safety issue AFAIK.
WORKER_STATE = {}
def stats(job_hash, queue)
tid = Sidekiq::Logging.tid
WORKER_STATE[tid] = {:queue => queue, :payload => job_hash, :run_at => Time.now.to_i }
begin
yield
rescue Exception
FAILURE.incr
raise
ensure
WORKER_STATE.delete(tid)
PROCESSED.incr
end
end
# Deep clone the arguments passed to the worker so that if
# the job fails, what is pushed back onto Redis hasn't
# been mutated by the worker.
def cloned(thing)
Marshal.load(Marshal.dump(thing))
end
def constantize(str)
names = str.split('::')
names.shift if names.empty? || names.first.empty?
names.inject(Object) do |constant, name|
# the false flag limits search for name to under the constant namespace
# which mimics Rails' behaviour
constant.const_defined?(name, false) ? constant.const_get(name, false) : constant.const_missing(name)
end
end
end
end