27e8e4b5d5
This is not exposed to a worker yet. It will continue the job and get an error when it tries to update the job's status to finished.
67 lines
2.4 KiB
Go
67 lines
2.4 KiB
Go
// Package jobqueue provides a generic interface to a simple job queue.
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//
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// Jobs are pushed to the queue with Enqueue(). Workers call Dequeue() to
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// receive a job and FinishJob() to report one as finished.
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//
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// Each job has a type and arguments corresponding to this type. These are
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// opaque to the job queue, but it mandates that the arguments must be
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// serializable to JSON. Similarly, a job's result has opaque result arguments
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// that are determined by its type.
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//
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// A job can have dependencies. It is not run until all its dependencies have
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// finished.
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package jobqueue
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import (
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"context"
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"errors"
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"time"
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"github.com/google/uuid"
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)
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// JobQueue is an interface to a simple job queue. It is safe for concurrent use.
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type JobQueue interface {
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// Enqueues a job.
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//
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// `args` must be JSON-serializable and fit the given `jobType`, i.e., a worker
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// that is running that job must know the format of `args`.
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//
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// All dependencies must already exist, but the job isn't run until all of them
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// have finished.
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//
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// Returns the id of the new job, or an error.
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Enqueue(jobType string, args interface{}, dependencies []uuid.UUID) (uuid.UUID, error)
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// Dequeues a job, blocking until one is available.
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//
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// Waits until a job with a type of any of `jobTypes` is available, or `ctx` is
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// canceled.
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//
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// All jobs in `jobTypes` must take the same type of `args`, corresponding to
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// the one that was passed to Enqueue().
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//
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// Returns the job's id or an error.
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Dequeue(ctx context.Context, jobTypes []string, args interface{}) (uuid.UUID, error)
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// Mark the job with `id` as finished. `result` must fit the associated
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// job type and must be serializable to JSON.
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FinishJob(id uuid.UUID, result interface{}) error
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// Cancel a job. Does nothing if the job has already finished.
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CancelJob(id uuid.UUID) error
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// Returns the current status of the job, in the form of three times:
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// queued, started, and finished. `started` and `finished` might be the
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// zero time (check with t.IsZero()), when the job is not running or
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// finished, respectively.
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//
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// If the job is finished, its result will be returned in `result`.
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JobStatus(id uuid.UUID, result interface{}) (queued, started, finished time.Time, canceled bool, err error)
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}
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var (
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ErrNotExist = errors.New("job does not exist")
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ErrNotRunning = errors.New("job is not running")
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ErrCanceled = errors.New("job ws canceled")
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)
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