mirror of
https://github.com/rclone/rclone.git
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38e70f1797
Add jobs.OnFinish method to register listener that will trigger when job is finished. Includes fix for stopping listeners.
367 lines
8.4 KiB
Go
367 lines
8.4 KiB
Go
// Manage background jobs that the rc is running
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package jobs
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import (
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"context"
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"fmt"
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"runtime/debug"
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"sync"
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"sync/atomic"
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"time"
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"github.com/pkg/errors"
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"github.com/rclone/rclone/fs"
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"github.com/rclone/rclone/fs/accounting"
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"github.com/rclone/rclone/fs/rc"
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)
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// Job describes an asynchronous task started via the rc package
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type Job struct {
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mu sync.Mutex
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ID int64 `json:"id"`
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Group string `json:"group"`
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StartTime time.Time `json:"startTime"`
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EndTime time.Time `json:"endTime"`
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Error string `json:"error"`
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Finished bool `json:"finished"`
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Success bool `json:"success"`
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Duration float64 `json:"duration"`
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Output rc.Params `json:"output"`
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Stop func() `json:"-"`
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listeners []*func()
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// realErr is the Error before printing it as a string, it's used to return
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// the real error to the upper application layers while still printing the
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// string error message.
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realErr error
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}
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// mark the job as finished
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func (job *Job) finish(out rc.Params, err error) {
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job.mu.Lock()
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job.EndTime = time.Now()
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if out == nil {
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out = make(rc.Params)
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}
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job.Output = out
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job.Duration = job.EndTime.Sub(job.StartTime).Seconds()
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if err != nil {
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job.realErr = err
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job.Error = err.Error()
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job.Success = false
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} else {
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job.realErr = nil
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job.Error = ""
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job.Success = true
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}
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job.Finished = true
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// Notify listeners that the job is finished
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for i := range job.listeners {
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go (*job.listeners[i])()
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}
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job.mu.Unlock()
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running.kickExpire() // make sure this job gets expired
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}
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func (job *Job) addListener(fn *func()) {
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job.mu.Lock()
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defer job.mu.Unlock()
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job.listeners = append(job.listeners, fn)
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}
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func (job *Job) removeListener(fn *func()) {
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job.mu.Lock()
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defer job.mu.Unlock()
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for i, ln := range job.listeners {
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if ln == fn {
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job.listeners = append(job.listeners[:i], job.listeners[i+1:]...)
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return
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}
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}
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}
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// run the job until completion writing the return status
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func (job *Job) run(ctx context.Context, fn rc.Func, in rc.Params) {
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defer func() {
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if r := recover(); r != nil {
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job.finish(nil, errors.Errorf("panic received: %v \n%s", r, string(debug.Stack())))
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}
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}()
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job.finish(fn(ctx, in))
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}
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// Jobs describes a collection of running tasks
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type Jobs struct {
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mu sync.RWMutex
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jobs map[int64]*Job
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opt *rc.Options
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expireRunning bool
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}
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var (
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running = newJobs()
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jobID = int64(0)
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)
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// newJobs makes a new Jobs structure
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func newJobs() *Jobs {
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return &Jobs{
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jobs: map[int64]*Job{},
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opt: &rc.DefaultOpt,
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}
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}
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// SetOpt sets the options when they are known
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func SetOpt(opt *rc.Options) {
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running.opt = opt
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}
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// SetInitialJobID allows for setting jobID before starting any jobs.
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func SetInitialJobID(id int64) {
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if !atomic.CompareAndSwapInt64(&jobID, 0, id) {
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panic("Setting jobID is only possible before starting any jobs")
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}
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}
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// kickExpire makes sure Expire is running
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func (jobs *Jobs) kickExpire() {
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jobs.mu.Lock()
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defer jobs.mu.Unlock()
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if !jobs.expireRunning {
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time.AfterFunc(jobs.opt.JobExpireInterval, jobs.Expire)
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jobs.expireRunning = true
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}
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}
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// Expire expires any jobs that haven't been collected
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func (jobs *Jobs) Expire() {
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jobs.mu.Lock()
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defer jobs.mu.Unlock()
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now := time.Now()
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for ID, job := range jobs.jobs {
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job.mu.Lock()
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if job.Finished && now.Sub(job.EndTime) > jobs.opt.JobExpireDuration {
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delete(jobs.jobs, ID)
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}
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job.mu.Unlock()
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}
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if len(jobs.jobs) != 0 {
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time.AfterFunc(jobs.opt.JobExpireInterval, jobs.Expire)
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jobs.expireRunning = true
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} else {
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jobs.expireRunning = false
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}
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}
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// IDs returns the IDs of the running jobs
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func (jobs *Jobs) IDs() (IDs []int64) {
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jobs.mu.RLock()
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defer jobs.mu.RUnlock()
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IDs = []int64{}
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for ID := range jobs.jobs {
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IDs = append(IDs, ID)
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}
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return IDs
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}
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// Get a job with a given ID or nil if it doesn't exist
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func (jobs *Jobs) Get(ID int64) *Job {
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jobs.mu.RLock()
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defer jobs.mu.RUnlock()
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return jobs.jobs[ID]
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}
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func getGroup(in rc.Params) string {
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// Check to see if the group is set
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group, err := in.GetString("_group")
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if rc.NotErrParamNotFound(err) {
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fs.Errorf(nil, "Can't get _group param %+v", err)
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}
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delete(in, "_group")
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return group
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}
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// NewAsyncJob start a new asynchronous Job off
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func (jobs *Jobs) NewAsyncJob(fn rc.Func, in rc.Params) *Job {
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id := atomic.AddInt64(&jobID, 1)
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group := getGroup(in)
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if group == "" {
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group = fmt.Sprintf("job/%d", id)
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}
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ctx := accounting.WithStatsGroup(context.Background(), group)
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ctx, cancel := context.WithCancel(ctx)
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stop := func() {
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cancel()
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// Wait for cancel to propagate before returning.
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<-ctx.Done()
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}
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job := &Job{
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ID: id,
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Group: group,
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StartTime: time.Now(),
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Stop: stop,
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}
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jobs.mu.Lock()
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jobs.jobs[job.ID] = job
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jobs.mu.Unlock()
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go job.run(ctx, fn, in)
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return job
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}
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// NewSyncJob start a new synchronous Job off
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func (jobs *Jobs) NewSyncJob(ctx context.Context, in rc.Params) (*Job, context.Context) {
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id := atomic.AddInt64(&jobID, 1)
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group := getGroup(in)
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if group == "" {
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group = fmt.Sprintf("job/%d", id)
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}
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ctxG := accounting.WithStatsGroup(ctx, fmt.Sprintf("job/%d", id))
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ctx, cancel := context.WithCancel(ctxG)
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stop := func() {
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cancel()
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// Wait for cancel to propagate before returning.
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<-ctx.Done()
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}
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job := &Job{
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ID: id,
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Group: group,
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StartTime: time.Now(),
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Stop: stop,
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}
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jobs.mu.Lock()
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jobs.jobs[job.ID] = job
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jobs.mu.Unlock()
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return job, ctx
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}
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// StartAsyncJob starts a new job asynchronously and returns a Param suitable
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// for output.
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func StartAsyncJob(fn rc.Func, in rc.Params) (rc.Params, error) {
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job := running.NewAsyncJob(fn, in)
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out := make(rc.Params)
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out["jobid"] = job.ID
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return out, nil
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}
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// ExecuteJob executes new job synchronously and returns a Param suitable for
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// output.
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func ExecuteJob(ctx context.Context, fn rc.Func, in rc.Params) (rc.Params, int64, error) {
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job, ctx := running.NewSyncJob(ctx, in)
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job.run(ctx, fn, in)
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return job.Output, job.ID, job.realErr
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}
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// OnFinish adds listener to jobid that will be triggered when job is finished.
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// It returns a function to cancel listening.
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func OnFinish(jobID int64, fn func()) (func(), error) {
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job := running.Get(jobID)
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if job == nil {
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return func() {}, errors.New("job not found")
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}
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if job.Finished {
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fn()
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} else {
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job.addListener(&fn)
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}
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return func() { job.removeListener(&fn) }, nil
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}
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func init() {
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rc.Add(rc.Call{
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Path: "job/status",
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Fn: rcJobStatus,
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Title: "Reads the status of the job ID",
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Help: `Parameters
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- jobid - id of the job (integer)
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Results
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- finished - boolean
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- duration - time in seconds that the job ran for
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- endTime - time the job finished (e.g. "2018-10-26T18:50:20.528746884+01:00")
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- error - error from the job or empty string for no error
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- finished - boolean whether the job has finished or not
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- id - as passed in above
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- startTime - time the job started (e.g. "2018-10-26T18:50:20.528336039+01:00")
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- success - boolean - true for success false otherwise
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- output - output of the job as would have been returned if called synchronously
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- progress - output of the progress related to the underlying job
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`,
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})
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}
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// Returns the status of a job
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func rcJobStatus(ctx context.Context, in rc.Params) (out rc.Params, err error) {
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jobID, err := in.GetInt64("jobid")
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if err != nil {
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return nil, err
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}
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job := running.Get(jobID)
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if job == nil {
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return nil, errors.New("job not found")
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}
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job.mu.Lock()
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defer job.mu.Unlock()
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out = make(rc.Params)
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err = rc.Reshape(&out, job)
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if err != nil {
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return nil, errors.Wrap(err, "reshape failed in job status")
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}
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return out, nil
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}
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func init() {
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rc.Add(rc.Call{
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Path: "job/list",
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Fn: rcJobList,
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Title: "Lists the IDs of the running jobs",
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Help: `Parameters - None
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Results
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- jobids - array of integer job ids
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`,
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})
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}
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// Returns list of job ids.
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func rcJobList(ctx context.Context, in rc.Params) (out rc.Params, err error) {
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out = make(rc.Params)
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out["jobids"] = running.IDs()
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return out, nil
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}
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func init() {
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rc.Add(rc.Call{
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Path: "job/stop",
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Fn: rcJobStop,
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Title: "Stop the running job",
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Help: `Parameters
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- jobid - id of the job (integer)
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`,
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})
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}
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// Stops the running job.
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func rcJobStop(ctx context.Context, in rc.Params) (out rc.Params, err error) {
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jobID, err := in.GetInt64("jobid")
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if err != nil {
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return nil, err
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}
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job := running.Get(jobID)
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if job == nil {
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return nil, errors.New("job not found")
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}
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job.mu.Lock()
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defer job.mu.Unlock()
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out = make(rc.Params)
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job.Stop()
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return out, nil
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}
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