/
traverser.go
649 lines (580 loc) · 23.7 KB
/
traverser.go
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// Copyright 2017-2018, Square, Inc.
package chain
import (
"fmt"
"sync"
"sync/atomic"
"time"
log "github.com/sirupsen/logrus"
"github.com/square/spincycle/v2/job-runner/runner"
"github.com/square/spincycle/v2/proto"
rm "github.com/square/spincycle/v2/request-manager"
"github.com/square/spincycle/v2/retry"
)
var (
// Returned when Stop is called but the chain has already been suspended.
ErrShuttingDown = fmt.Errorf("chain not stopped because traverser is shutting down")
)
const (
// Default timeout used by traverser factory for traverser's stopTimeout
// and sendTimeout.
defaultTimeout = 10 * time.Second
// Number of times to attempt sending a job log to the RM.
jobLogTries = 3
// Time to wait between attempts to send a job log to RM.
jobLogRetryWait = 500 * time.Millisecond
// Number of times to attempt sending chain state / SJC to RM in Reaper.
reaperTries = 5
// Time to wait between tries to send chain state/SJC to RM.
reaperRetryWait = 500 * time.Millisecond
)
// A Traverser provides the ability to run a job chain while respecting the
// dependencies between the jobs.
type Traverser interface {
// Run traverses a job chain and runs all of the jobs in it. It starts by
// running the first job in the chain, and then, if the job completed,
// successfully, running its adjacent jobs. This process continues until there
// are no more jobs to run, or until the Stop method is called on the traverser.
Run()
// Stop makes a traverser stop traversing its job chain. It also sends a stop
// signal to all of the jobs that a traverser is running.
//
// It returns an error if it fails to stop all running jobs.
Stop() error
// Running returns all currently running jobs. The status.Manager uses this
// to report running status.
Running() []proto.JobStatus
}
// A TraverserFactory makes a new Traverser.
type TraverserFactory interface {
Make(*proto.JobChain) (Traverser, error)
MakeFromSJC(*proto.SuspendedJobChain) (Traverser, error)
}
type traverserFactory struct {
chainRepo Repo
rf runner.Factory
rmc rm.Client
shutdownChan chan struct{}
}
func NewTraverserFactory(chainRepo Repo, rf runner.Factory, rmc rm.Client, shutdownChan chan struct{}) TraverserFactory {
return &traverserFactory{
chainRepo: chainRepo,
rf: rf,
rmc: rmc,
shutdownChan: shutdownChan,
}
}
// Make makes a Traverser for the job chain. The chain is first validated
// and saved to the chain repo.
func (f *traverserFactory) Make(jobChain *proto.JobChain) (Traverser, error) {
// Convert/wrap chain from proto to Go object.
chain := NewChain(jobChain, make(map[string]uint), make(map[string]uint), make(map[string]uint))
return f.make(chain)
}
// MakeFromSJC makes a Traverser from a suspended job chain.
func (f *traverserFactory) MakeFromSJC(sjc *proto.SuspendedJobChain) (Traverser, error) {
// Convert/wrap chain from proto to Go object.
chain := NewChain(sjc.JobChain, sjc.SequenceTries, sjc.TotalJobTries, sjc.LatestRunJobTries)
logger := log.WithFields(log.Fields{"request_id": sjc.RequestId})
logger.Infof("resuming request")
// Change all STOPPED jobs to PENDING. Traverser expects a ready-to-run chain.
// We used to change stopped -> running in runJobs, but if two jobs are stopped
// and the first is ran and reaped before the 2nd starts, the reaper will call
// IsDoneRunning which will return done=true because of the 2nd stopped job.
for _, job := range sjc.JobChain.Jobs {
if job.State != proto.STATE_STOPPED {
continue
}
// Current job try count is the job try on which it was stopped.
// We -1 that count because the runner does current+1. E.g.: if tries=2
// here (stopped on 2nd try), we'll send tries=1 to runner and it'll
// re-run as try=2.
chain.IncrementJobTries(job.Id, -1)
chain.SetJobState(job.Id, proto.STATE_PENDING)
logger.Infof("resuming from job %s (%s)", job.Name, job.Id)
// Same applies to seq tries. If this is seq start job, then previous
// run would have +1 the count, so we need to -1 it because it's going
// to +1 again in runJobs.
if chain.IsSequenceStartJob(job.Id) {
chain.IncrementSequenceTries(job.Id, -1)
}
}
return f.make(chain)
}
// Creates a new Traverser from a chain. Used for both new and resumed chains.
func (f *traverserFactory) make(chain *Chain) (Traverser, error) {
// Add chain to repo. This used to save the chain in Redis, if configured,
// but now it's only an in-memory map. The only functionality it serves is
// preventing this JR instance from running the same job chain.
if err := f.chainRepo.Add(chain); err != nil {
return nil, fmt.Errorf("error adding job chain: %s", err)
}
// Create and return a traverser for the chain. The traverser is responsible
// for the chain: running, cleaning up, removing from repo when done, etc.
// And traverser and chain have the same lifespan: traverser is done when
// chain is done.
cfg := TraverserConfig{
Chain: chain,
ChainRepo: f.chainRepo,
RunnerFactory: f.rf,
RMClient: f.rmc,
ShutdownChan: f.shutdownChan,
StopTimeout: defaultTimeout,
SendTimeout: defaultTimeout,
}
return NewTraverser(cfg), nil
}
// -------------------------------------------------------------------------- //
type traverser struct {
reaperFactory ReaperFactory
reaper JobReaper
shutdownChan chan struct{} // indicates JR is shutting down
runJobChan chan proto.Job // jobs to be run
doneJobChan chan proto.Job // jobs that are done
doneChan chan struct{} // closed when traverser finishes running
stopMux *sync.RWMutex // lock around checks to stopped
stopped bool // has traverser been stopped
suspended bool // has traverser been suspended
stopChan chan struct{} // don't run jobs in runJobs
pendingChan chan struct{} // runJobs closes on return
pending int64 // N runJob goroutines are pending runnerRepo.Set
chain *Chain
chainRepo Repo // stores all currently running chains
rf runner.Factory
runnerRepo runner.Repo // stores actively running jobs
rmc rm.Client
logger *log.Entry
stopTimeout time.Duration // Time to wait for jobs to stop
sendTimeout time.Duration // Time to wait for a job to send on doneJobChan.
}
type TraverserConfig struct {
Chain *Chain
ChainRepo Repo
RunnerFactory runner.Factory
RMClient rm.Client
ShutdownChan chan struct{}
StopTimeout time.Duration
SendTimeout time.Duration
}
func NewTraverser(cfg TraverserConfig) *traverser {
logger := log.WithFields(log.Fields{"request_id": cfg.Chain.RequestId()})
// Channels used to communicate between traverser + reaper(s)
doneJobChan := make(chan proto.Job)
runJobChan := make(chan proto.Job)
// Each traverser has its own runner repo because it's keyed on job ID and
// job IDs are unique per-chain, not globally.
runnerRepo := runner.NewRepo()
// Reaper factory makes one of three reapers: running, stopped, or suspended
// reaper. Normally, only the running reaper is used. Its swapped out for
// one of the other two if the request is stopped or suspended, respectively.
reaperFactory := &ChainReaperFactory{
Chain: cfg.Chain,
ChainRepo: cfg.ChainRepo,
RMClient: cfg.RMClient,
RMCTries: reaperTries,
RMCRetryWait: reaperRetryWait,
Logger: logger,
DoneJobChan: doneJobChan,
RunJobChan: runJobChan,
RunnerRepo: runnerRepo,
}
return &traverser{
reaperFactory: reaperFactory,
logger: logger,
chain: cfg.Chain,
chainRepo: cfg.ChainRepo,
rf: cfg.RunnerFactory,
runnerRepo: runnerRepo,
shutdownChan: cfg.ShutdownChan,
runJobChan: runJobChan,
doneJobChan: doneJobChan,
doneChan: make(chan struct{}),
stopChan: make(chan struct{}),
pendingChan: make(chan struct{}),
rmc: cfg.RMClient,
stopMux: &sync.RWMutex{},
stopTimeout: cfg.StopTimeout,
sendTimeout: cfg.SendTimeout,
}
}
// Run runs all jobs in the chain and blocks until the chain finishes running, is
// stopped, or is suspended.
func (t *traverser) Run() {
t.logger.Infof("traverser.Run call")
defer t.logger.Infof("traverser.Run return")
defer t.chainRepo.Remove(t.chain.RequestId())
// Start a goroutine to run jobs. This consumes runJobChan. When jobs are done,
// they're sent to doneJobChan, which a reaper consumes. This goroutine returns
// when runJobChan is closed below.
go t.runJobs()
// Enqueue all the first runnable jobs
for _, job := range t.chain.RunnableJobs() {
t.logger.Infof("initial job: %s (%s)", job.Name, job.Id)
t.runJobChan <- job
}
// Start a goroutine to reap done jobs. The runningReaper consumes from
// doneJobChan and sends the next jobs to be run to runJobChan. Stop()
// calls t.reaper.Stop(), which is this reaper. The close(t.runJobChan)
// causes runJobs() (started above ^) to return.
runningReaperChan := make(chan struct{})
t.reaper = t.reaperFactory.MakeRunning() // t.reaper = runningReaper
go func() {
defer close(runningReaperChan) // indicate reaper is done (see select below)
defer close(t.runJobChan) // stop runJobs goroutine
t.reaper.Run()
}()
// Wait for running reaper to be done or traverser to be shut down.
select {
case <-runningReaperChan:
// If running reaper is done because traverser was stopped, we will
// wait for Stop() to finish. Otherwise, the chain finished normally
// (completed or failed) and we can return right away.
//
// We don't check if the chain was suspended, since that can only
// happen via the other case in this select.
t.stopMux.Lock()
if !t.stopped {
t.stopMux.Unlock()
return
}
t.stopMux.Unlock()
case <-t.shutdownChan:
// The Job Runner is shutting down. Stop the running reaper and suspend
// the job chain, to be resumed later by another Job Runner.
t.shutdown()
}
// Traverser is being stopped or shut down - wait for that to finish before
// returning.
select {
case <-t.doneChan:
// Stopped/shutdown successfully - nothing left to do.
return
case <-time.After(20 * time.Second):
// Failed to stop/shutdown in a reasonable amount of time.
// Log the failure and return.
t.logger.Warnf("stopping or suspending the job chain took too long. Exiting...")
return
}
}
// Stop stops the running job chain by switching the running chain reaper for a
// stopped chain reaper and stopping all currently running jobs. Stop blocks until
// all jobs have finished and the stopped reaper has send the chain's final state
// to the RM.
func (t *traverser) Stop() error {
// Don't do anything if the traverser has already been stopped or suspended.
t.stopMux.Lock()
defer t.stopMux.Unlock()
if t.stopped {
return nil
} else if t.suspended {
return ErrShuttingDown
}
close(t.stopChan)
t.stopped = true
t.logger.Infof("stopping traverser and all jobs")
// Stop the runningReaper and start the stoppedReaper which saves jobs' states
// but doesn't enqueue any more jobs to run. It sends the chain's final state
// to the RM when all jobs have stopped running.
t.reaper.Stop() // blocks until runningReaper stops
stoppedReaperChan := make(chan struct{})
t.reaper = t.reaperFactory.MakeStopped() // t.reaper = stoppedReaper
go func() {
defer close(stoppedReaperChan)
t.reaper.Run()
}()
// Stop all job runners in the runner repo. Do this after switching to the
// stopped reaper so that when the jobs finish and are sent on doneJobChan,
// they are reaped correctly.
timeout := time.After(t.stopTimeout)
err := t.stopRunningJobs(timeout)
if err != nil {
// Don't return the error yet - we still want to wait for the stop
// reaper to be done.
err = fmt.Errorf("traverser was stopped, but encountered an error in the process: %s", err)
}
// Wait for the stopped reaper to finish. If it takes too long, some jobs
// haven't respond quickly to being stopped. Stop waiting for these jobs by
// stopping the stopped reaper.
select {
case <-stoppedReaperChan:
case <-timeout:
t.logger.Warnf("timed out waiting for jobs to stop - stopping reaper")
t.reaper.Stop()
}
close(t.doneChan)
return err
}
func (t *traverser) Running() []proto.JobStatus {
runners := t.runnerRepo.Items() // map[string]Runner keyed on jobId
jobStatus := make([]proto.JobStatus, 0, len(runners)) // for each runner
reqId := t.chain.RequestId()
for _, r := range runners {
rs := r.Status() // real-time status and more
js := proto.JobStatus{
RequestId: reqId,
JobId: rs.Job.Id,
Type: rs.Job.Type,
Name: rs.Job.Name,
State: t.chain.JobState(rs.Job.Id),
StartedAt: rs.StartedAt.UnixNano(),
Try: rs.Try,
Status: rs.Status,
}
jobStatus = append(jobStatus, js)
}
return jobStatus
}
// -------------------------------------------------------------------------- //
// runJobs loops on the runJobChan, and runs each job that comes through the
// channel. When the job is done, it sends the job out through the doneJobChan
// which is being consumed by a reaper.
func (t *traverser) runJobs() {
t.logger.Info("runJobs call")
defer t.logger.Info("runJobs return")
defer close(t.pendingChan)
// Run all jobs that come in on runJobChan. The loop exits when runJobChan
// is closed in the runningReaper goroutine in Run().
for job := range t.runJobChan {
// Don't run the job if traverser stopped or shutting down. In this case,
// drain runJobChan to prevent runningReaper from blocking (the chan is
// unbuffered). As long as we do not add job to runner repo, or do anything
// to the job, it's like the job never ran; it stays pending and tries=0.
//
// Must check before running goroutine because Run() closes runJobChan
// when the runningReaper is done. Then this loop will end and close
// pendingChan which stopRunningJobs blocks on. Since this check happens
// in loop not goroutine, a closed pendingChan means it's been checked
// for all jobs and either the job did not run or it did with pending+1
// because the loop won't finish until running all code before the goroutine
// is launched.
select {
case <-t.stopChan:
log.Infof("not running job %s: traverser stopped or shutting down", job.Id)
continue
default:
}
// Signal to stopRunningJobs that there's +1 goroutine that's going
// to add itself to runnerRepo
atomic.AddInt64(&t.pending, 1)
// Explicitly pass the job into the func, or all goroutines would share
// the same loop "job" variable.
go func(job proto.Job) {
jLogger := t.logger.WithFields(log.Fields{"job_id": job.Id, "sequence_id": job.SequenceId, "sequence_try": t.chain.SequenceTries(job.Id)})
// If this is sequence start job (which currently means sequenceId == job.Id),
// wait for duration of SequenceRetryWait, then increment sequence try count.
if t.chain.IsSequenceStartJob(job.Id) {
if t.chain.SequenceTries(job.Id) != 0 {
jLogger.Infof(fmt.Sprintf("waiting %s before retrying sequence", job.SequenceRetryWait))
retryWait, _ := time.ParseDuration(job.SequenceRetryWait) // checked that this parses in RM
select {
case <-time.After(retryWait): // wait before retry
case <-t.stopChan:
jLogger.Infof("traverser was stopped - exiting sequence retry wait early and not running job")
atomic.AddInt64(&t.pending, -1)
return
}
}
t.chain.IncrementSequenceTries(job.Id, 1)
jLogger.Infof("sequence try %d", t.chain.SequenceTries(job.Id))
}
// Always send the finished job to doneJobChan to be reaped. If the
// reaper isn't reaping any more jobs (if this job took too long to
// finish after being stopped), sending to doneJobChan won't be
// possible - timeout after a while so we don't leak this goroutine.
defer func() {
select {
case t.doneJobChan <- job: // reap the done job
case <-time.After(t.sendTimeout):
jLogger.Warnf("timed out sending job to doneJobChan")
}
// Remove the job's runner from the repo (if it was ever added)
// AFTER sending it to doneJobChan. This avoids a race condition
// when the stopped + suspended reapers check if the runnerRepo
// is empty.
t.runnerRepo.Remove(job.Id)
}()
// Job tries for current sequence try and total tries for all seq tries.
// For new chains, these are zero. For suspended/resumed chains they can
// be > 0 which is why we pass them to the job runner: to resume for the
// last counts.
curTries, totalTries := t.chain.JobTries(job.Id)
runner, err := t.rf.Make(job, t.chain.RequestId(), curTries, totalTries)
if err != nil {
// Problem creating the job runner - treat job as failed.
// Send a JobLog to the RM so that it knows this job failed.
atomic.AddInt64(&t.pending, -1)
job.State = proto.STATE_FAIL
err = fmt.Errorf("problem creating job runner: %s", err)
t.sendJL(job, err)
return
}
// --------------------------------------------------------------
// Add the runner to the repo. Runners in the repo are used
// by the Status, Stop, and shutdown methods on the traverser.
// Then decrement pending to signal to stopRunningJobs that
// there's one less goroutine it nees to wait for.
t.runnerRepo.Set(job.Id, runner)
atomic.AddInt64(&t.pending, -1)
// Run the job. This is a blocking operation that could take a long time.
jLogger.Infof("running job")
t.chain.SetJobState(job.Id, proto.STATE_RUNNING)
ret := runner.Run(job.Data)
jLogger.Infof("job done: state=%s (%d)", proto.StateName[ret.FinalState], ret.FinalState)
// We don't pass the Chain to the job runner, so it can't call this
// itself. Instead, it returns how many tries it did, and we set it.
t.chain.IncrementJobTries(job.Id, int(ret.Tries))
// Set job final state because this job is about to be reaped on
// the doneJobChan, sent in this goroutine's defer func at top ^.
job.State = ret.FinalState
}(job)
}
}
// sendJL sends a job log to the Request Manager.
func (t *traverser) sendJL(job proto.Job, err error) {
_, totalTries := t.chain.JobTries(job.Id)
jLogger := t.logger.WithFields(log.Fields{"job_id": job.Id})
jl := proto.JobLog{
RequestId: t.chain.RequestId(),
JobId: job.Id,
Name: job.Name,
Type: job.Type,
Try: totalTries,
StartedAt: 0, // zero because the job never ran
FinishedAt: 0,
State: job.State,
Exit: 1,
}
if err != nil {
jl.Error = err.Error()
}
err = retry.Do(jobLogTries, jobLogRetryWait,
func() error {
return t.rmc.CreateJL(t.chain.RequestId(), jl)
},
nil,
)
if err != nil {
jLogger.Errorf("problem sending job log (%#v) to the Request Manager: %s", jl, err)
}
}
// shutdown suspends the running chain by switching the running chain reaper for a
// suspended chain reaper and stopping all currently running jobs. Once all jobs
// have finished, the suspended reaper informs the RM about the suspended chain by
// sending a SuspendedJobChain.
//
// When a Job Runner is shutting down, all of its traversers are shut down and their
// running job chains suspended. The Request Manager can later resume these job
// chains by sending them to a running Job Runner instance.
func (t *traverser) shutdown() {
// Don't do anything if the traverser has already been stopped or suspended.
t.stopMux.Lock()
defer t.stopMux.Unlock()
if t.stopped || t.suspended {
return
}
close(t.stopChan)
t.suspended = true
t.logger.Info("suspending job chain - stopping all jobs")
// Stop the runningReaper and start the suspendedReaper which saves jobs'
// states and prepares the chain to be resumed later but doesn't enqueue
// any more jobs to run. When all jobs have stopped running, it sends a
// SuspendedJobChain to the RM, or the final state if the chain completed
// or failed.
t.reaper.Stop() // blocks until runningReaper stops
suspendedReaperChan := make(chan struct{})
t.reaper = t.reaperFactory.MakeSuspended() // t.reaper = suspendedReaper
go func() {
defer close(suspendedReaperChan)
t.reaper.Run()
}()
// Stop all job runners in the runner repo. Do this after switching to the
// suspended reaper so that when the jobs finish and are sent on doneJobChan,
// they are reaped correctly.
timeout := time.After(t.stopTimeout)
err := t.stopRunningJobs(timeout)
if err != nil {
t.logger.Errorf("problem suspending job chain: %s", err)
}
// Wait for suspended reaper to finish. If it takes too long, some jobs
// haven't respond quickly to being stopped. Stop waiting for these jobs by
// stopping the suspended reaper.
select {
case <-suspendedReaperChan:
case <-timeout:
t.logger.Warnf("timed out waiting for jobs to stop - stopping reaper")
t.reaper.Stop()
}
close(t.doneChan)
}
// stopRunningJobs stops all currently running jobs.
func (t *traverser) stopRunningJobs(timeout <-chan time.Time) error {
// To stop all running jobs without race coditions, we need to know:
// 1. runJobs is done, won't start any more goroutines
// 2. All in-flight runJob goroutines have added themselves to runner repo
// First is easy: wait for it to close pendingChan. Second is like a wait
// group wait: runJobs add +1 to pending when goroutine starts, and -1 after
// it adds itself to runner repo. So all runJob goroutines have added
// themselves to the runner repo when pending == 0.
//
// The shutdown sequence is:
// 1. close(stopChan): runJob goroutines (RGs) don't run if closed. It's
// as if the job never ran. This allows runJobChan to drain and prevents
// runnerRepo from blocking because the chan is unbuffered. This is done
// in the for loop, before launching the goroutine, so that a closed
// pendingChan (step 4) guarantees that runJobs either didn't run an
// RG or it did and added it to pending count (because the loop won't
// exit until running pre-goroutine code, and pendingChan is only closed
// after loop exits).
// 2. Stop runningReaper: This stops new/next jobs into runJobChan, which
// is being drained because of step 1.
// 3. close(runJobChan): When runningReaper.Run returns, the goroutine in
// in traverser.Run closes runJobChan. Since runningReaper is only thing
// that sends to runJobChan, it must be closed like this so runningReaper
// doesn't panic on "send on closed channel".
// 4. close(pendingChan): Given step 3 and step 1, eventually runJobChan
// will drain and runJobs() will return, closing pendingChan when it does.
// 5. Call stopRunningJobs: This func waits for step 4, which ensures no
// more RGs. And given step 1, we're assured that all in-flight RGs
// have added themsevs to pending count. Therefore, this func waits for
// pending count == 0 which means all RGs have added themselves to the
// runner repo.
// 6. Stop all active runners in runner repo.
// Wait for runJobs to return
select {
case <-t.pendingChan:
case <-timeout:
return fmt.Errorf("stopRunningJobs: timeout waiting for pendingChan")
}
// Wait for in-flight runJob goroutines to add themselves to runner repo
if n := atomic.LoadInt64(&t.pending); n > 0 {
for atomic.LoadInt64(&t.pending) > 0 {
select {
case <-timeout:
return fmt.Errorf("stopRunningJobs: timeout waiting for pending count")
default:
time.Sleep(100 * time.Millisecond)
}
}
}
// Stop all runners in parallel in case some jobs don't stop quickly
activeRunners := t.runnerRepo.Items()
t.logger.Printf("stopping %d active job runners", len(activeRunners))
var wg sync.WaitGroup
hadError := false
for jobId, activeRunner := range activeRunners {
wg.Add(1)
go func(runner runner.Runner) {
defer wg.Done()
if err := runner.Stop(); err != nil {
t.logger.Errorf("problem stopping job runner (job id = %s): %s", jobId, err)
hadError = true
}
}(activeRunner)
}
wg.Wait()
// If there was an error when stopping at least one of the jobs, return it.
if hadError {
return fmt.Errorf("problem stopping one or more job runners - see logs for more info")
}
return nil
}