7bfcee36f8
Channels are a concept similar to job types. Callers must specify a channel name when queueing a new job. A list of channels is also specified when dequeueing a job. The dequeued job's channel will always be from one of the specified channel. Of course, the job types are also respected. The dequeued job will also always be from one of the specified type. Currently, all calls to jobqueue were changed so all queue operations use an empty channel name and all dequeue operations use a list containing an empty channel. Thus, this is a non-functional change. Signed-off-by: Ondřej Budai <ondrej@budai.cz>
88 lines
3.5 KiB
Go
88 lines
3.5 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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"encoding/json"
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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, channel string) (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` and any of `channels`
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// is available, or `ctx` is canceled.
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//
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// Returns the job's id, token, dependencies, type, and arguments, or an error. Arguments
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// can be unmarshaled to the type given in Enqueue().
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Dequeue(ctx context.Context, jobTypes []string, channels []string) (uuid.UUID, uuid.UUID, []uuid.UUID, string, json.RawMessage, error)
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// Dequeues a pending job by its ID in a non-blocking way.
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//
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// Returns the job's token, dependencies, type, and arguments, or an error. Arguments
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// can be unmarshaled to the type given in Enqueue().
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DequeueByID(ctx context.Context, id uuid.UUID) (uuid.UUID, []uuid.UUID, string, json.RawMessage, 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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// If the job has finished, returns the result as raw JSON.
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//
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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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// Lastly, the IDs of the jobs dependencies are returned.
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JobStatus(id uuid.UUID) (jobType string, result json.RawMessage, queued, started, finished time.Time, canceled bool, deps []uuid.UUID, err error)
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// Job returns all the parameters that define a job (everything provided during Enqueue).
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Job(id uuid.UUID) (jobType string, args json.RawMessage, dependencies []uuid.UUID, channel string, err error)
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// Find job by token, this will return an error if the job hasn't been dequeued
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IdFromToken(token uuid.UUID) (id uuid.UUID, err error)
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// Get a list of tokens which haven't been updated in the specified time frame
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Heartbeats(olderThan time.Duration) (tokens []uuid.UUID)
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// Reset the last heartbeat time to time.Now()
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RefreshHeartbeat(token uuid.UUID)
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}
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var (
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ErrNotExist = errors.New("job does not exist")
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ErrNotPending = errors.New("job is not pending")
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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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ErrDequeueTimeout = errors.New("dequeue context timed out or was canceled")
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)
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