rclone/fs/rc/jobs/job.go
Nick Craig-Wood e43b5ce5e5 Remove github.com/pkg/errors and replace with std library version
This is possible now that we no longer support go1.12 and brings
rclone into line with standard practices in the Go world.

This also removes errors.New and errors.Errorf from lib/errors and
prefers the stdlib errors package over lib/errors.
2021-11-07 11:53:30 +00:00

408 lines
9.4 KiB
Go

// Manage background jobs that the rc is running
package jobs
import (
"context"
"errors"
"fmt"
"runtime/debug"
"sync"
"sync/atomic"
"time"
"github.com/rclone/rclone/fs"
"github.com/rclone/rclone/fs/accounting"
"github.com/rclone/rclone/fs/filter"
"github.com/rclone/rclone/fs/rc"
)
// Job describes an asynchronous task started via the rc package
type Job struct {
mu sync.Mutex
ID int64 `json:"id"`
Group string `json:"group"`
StartTime time.Time `json:"startTime"`
EndTime time.Time `json:"endTime"`
Error string `json:"error"`
Finished bool `json:"finished"`
Success bool `json:"success"`
Duration float64 `json:"duration"`
Output rc.Params `json:"output"`
Stop func() `json:"-"`
listeners []*func()
// realErr is the Error before printing it as a string, it's used to return
// the real error to the upper application layers while still printing the
// string error message.
realErr error
}
// mark the job as finished
func (job *Job) finish(out rc.Params, err error) {
job.mu.Lock()
job.EndTime = time.Now()
if out == nil {
out = make(rc.Params)
}
job.Output = out
job.Duration = job.EndTime.Sub(job.StartTime).Seconds()
if err != nil {
job.realErr = err
job.Error = err.Error()
job.Success = false
} else {
job.realErr = nil
job.Error = ""
job.Success = true
}
job.Finished = true
// Notify listeners that the job is finished
for i := range job.listeners {
go (*job.listeners[i])()
}
job.mu.Unlock()
running.kickExpire() // make sure this job gets expired
}
func (job *Job) addListener(fn *func()) {
job.mu.Lock()
defer job.mu.Unlock()
job.listeners = append(job.listeners, fn)
}
func (job *Job) removeListener(fn *func()) {
job.mu.Lock()
defer job.mu.Unlock()
for i, ln := range job.listeners {
if ln == fn {
job.listeners = append(job.listeners[:i], job.listeners[i+1:]...)
return
}
}
}
// run the job until completion writing the return status
func (job *Job) run(ctx context.Context, fn rc.Func, in rc.Params) {
defer func() {
if r := recover(); r != nil {
job.finish(nil, fmt.Errorf("panic received: %v \n%s", r, string(debug.Stack())))
}
}()
job.finish(fn(ctx, in))
}
// Jobs describes a collection of running tasks
type Jobs struct {
mu sync.RWMutex
jobs map[int64]*Job
opt *rc.Options
expireRunning bool
}
var (
running = newJobs()
jobID = int64(0)
)
// newJobs makes a new Jobs structure
func newJobs() *Jobs {
return &Jobs{
jobs: map[int64]*Job{},
opt: &rc.DefaultOpt,
}
}
// SetOpt sets the options when they are known
func SetOpt(opt *rc.Options) {
running.opt = opt
}
// SetInitialJobID allows for setting jobID before starting any jobs.
func SetInitialJobID(id int64) {
if !atomic.CompareAndSwapInt64(&jobID, 0, id) {
panic("Setting jobID is only possible before starting any jobs")
}
}
// kickExpire makes sure Expire is running
func (jobs *Jobs) kickExpire() {
jobs.mu.Lock()
defer jobs.mu.Unlock()
if !jobs.expireRunning {
time.AfterFunc(jobs.opt.JobExpireInterval, jobs.Expire)
jobs.expireRunning = true
}
}
// Expire expires any jobs that haven't been collected
func (jobs *Jobs) Expire() {
jobs.mu.Lock()
defer jobs.mu.Unlock()
now := time.Now()
for ID, job := range jobs.jobs {
job.mu.Lock()
if job.Finished && now.Sub(job.EndTime) > jobs.opt.JobExpireDuration {
delete(jobs.jobs, ID)
}
job.mu.Unlock()
}
if len(jobs.jobs) != 0 {
time.AfterFunc(jobs.opt.JobExpireInterval, jobs.Expire)
jobs.expireRunning = true
} else {
jobs.expireRunning = false
}
}
// IDs returns the IDs of the running jobs
func (jobs *Jobs) IDs() (IDs []int64) {
jobs.mu.RLock()
defer jobs.mu.RUnlock()
IDs = []int64{}
for ID := range jobs.jobs {
IDs = append(IDs, ID)
}
return IDs
}
// Get a job with a given ID or nil if it doesn't exist
func (jobs *Jobs) Get(ID int64) *Job {
jobs.mu.RLock()
defer jobs.mu.RUnlock()
return jobs.jobs[ID]
}
// Check to see if the group is set
func getGroup(ctx context.Context, in rc.Params, id int64) (context.Context, string, error) {
group, err := in.GetString("_group")
if rc.NotErrParamNotFound(err) {
return ctx, "", err
}
delete(in, "_group")
if group == "" {
group = fmt.Sprintf("job/%d", id)
}
ctx = accounting.WithStatsGroup(ctx, group)
return ctx, group, nil
}
// See if _async is set returning a boolean and a possible new context
func getAsync(ctx context.Context, in rc.Params) (context.Context, bool, error) {
isAsync, err := in.GetBool("_async")
if rc.NotErrParamNotFound(err) {
return ctx, false, err
}
delete(in, "_async") // remove the async parameter after parsing
if isAsync {
// unlink this job from the current context
ctx = context.Background()
}
return ctx, isAsync, nil
}
// See if _config is set and if so adjust ctx to include it
func getConfig(ctx context.Context, in rc.Params) (context.Context, error) {
if _, ok := in["_config"]; !ok {
return ctx, nil
}
ctx, ci := fs.AddConfig(ctx)
err := in.GetStruct("_config", ci)
if err != nil {
return ctx, err
}
delete(in, "_config") // remove the parameter
return ctx, nil
}
// See if _filter is set and if so adjust ctx to include it
func getFilter(ctx context.Context, in rc.Params) (context.Context, error) {
if _, ok := in["_filter"]; !ok {
return ctx, nil
}
// Copy of the current filter options
opt := filter.GetConfig(ctx).Opt
// Update the options from the parameter
err := in.GetStruct("_filter", &opt)
if err != nil {
return ctx, err
}
fi, err := filter.NewFilter(&opt)
if err != nil {
return ctx, err
}
ctx = filter.ReplaceConfig(ctx, fi)
delete(in, "_filter") // remove the parameter
return ctx, nil
}
// NewJob creates a Job and executes it, possibly in the background if _async is set
func (jobs *Jobs) NewJob(ctx context.Context, fn rc.Func, in rc.Params) (job *Job, out rc.Params, err error) {
id := atomic.AddInt64(&jobID, 1)
in = in.Copy() // copy input so we can change it
ctx, isAsync, err := getAsync(ctx, in)
if err != nil {
return nil, nil, err
}
ctx, err = getConfig(ctx, in)
if err != nil {
return nil, nil, err
}
ctx, err = getFilter(ctx, in)
if err != nil {
return nil, nil, err
}
ctx, group, err := getGroup(ctx, in, id)
if err != nil {
return nil, nil, err
}
ctx, cancel := context.WithCancel(ctx)
stop := func() {
cancel()
// Wait for cancel to propagate before returning.
<-ctx.Done()
}
job = &Job{
ID: id,
Group: group,
StartTime: time.Now(),
Stop: stop,
}
jobs.mu.Lock()
jobs.jobs[job.ID] = job
jobs.mu.Unlock()
if isAsync {
go job.run(ctx, fn, in)
out = make(rc.Params)
out["jobid"] = job.ID
err = nil
} else {
job.run(ctx, fn, in)
out = job.Output
err = job.realErr
}
return job, out, err
}
// NewJob creates a Job and executes it on the global job queue,
// possibly in the background if _async is set
func NewJob(ctx context.Context, fn rc.Func, in rc.Params) (job *Job, out rc.Params, err error) {
return running.NewJob(ctx, fn, in)
}
// OnFinish adds listener to jobid that will be triggered when job is finished.
// It returns a function to cancel listening.
func OnFinish(jobID int64, fn func()) (func(), error) {
job := running.Get(jobID)
if job == nil {
return func() {}, errors.New("job not found")
}
if job.Finished {
fn()
} else {
job.addListener(&fn)
}
return func() { job.removeListener(&fn) }, nil
}
func init() {
rc.Add(rc.Call{
Path: "job/status",
Fn: rcJobStatus,
Title: "Reads the status of the job ID",
Help: `Parameters:
- jobid - id of the job (integer).
Results:
- finished - boolean
- duration - time in seconds that the job ran for
- endTime - time the job finished (e.g. "2018-10-26T18:50:20.528746884+01:00")
- error - error from the job or empty string for no error
- finished - boolean whether the job has finished or not
- id - as passed in above
- startTime - time the job started (e.g. "2018-10-26T18:50:20.528336039+01:00")
- success - boolean - true for success false otherwise
- output - output of the job as would have been returned if called synchronously
- progress - output of the progress related to the underlying job
`,
})
}
// Returns the status of a job
func rcJobStatus(ctx context.Context, in rc.Params) (out rc.Params, err error) {
jobID, err := in.GetInt64("jobid")
if err != nil {
return nil, err
}
job := running.Get(jobID)
if job == nil {
return nil, errors.New("job not found")
}
job.mu.Lock()
defer job.mu.Unlock()
out = make(rc.Params)
err = rc.Reshape(&out, job)
if err != nil {
return nil, fmt.Errorf("reshape failed in job status: %w", err)
}
return out, nil
}
func init() {
rc.Add(rc.Call{
Path: "job/list",
Fn: rcJobList,
Title: "Lists the IDs of the running jobs",
Help: `Parameters: None.
Results:
- jobids - array of integer job ids.
`,
})
}
// Returns list of job ids.
func rcJobList(ctx context.Context, in rc.Params) (out rc.Params, err error) {
out = make(rc.Params)
out["jobids"] = running.IDs()
return out, nil
}
func init() {
rc.Add(rc.Call{
Path: "job/stop",
Fn: rcJobStop,
Title: "Stop the running job",
Help: `Parameters:
- jobid - id of the job (integer).
`,
})
}
// Stops the running job.
func rcJobStop(ctx context.Context, in rc.Params) (out rc.Params, err error) {
jobID, err := in.GetInt64("jobid")
if err != nil {
return nil, err
}
job := running.Get(jobID)
if job == nil {
return nil, errors.New("job not found")
}
job.mu.Lock()
defer job.mu.Unlock()
out = make(rc.Params)
job.Stop()
return out, nil
}