Fast and reliable background jobs in Go
RequireNotInserted test helper (in addition to the existing RequireInserted) that verifies that a job with matching conditions was not inserted. PR #237.scheduled_at of inserted jobs to the more precise time of when they were scheduled to run, as opposed to when they were inserted. PR #341.github.com/lib/pq, making it once again a test-only dependency. PR #337.⚠️ Version 0.5.0 contains a new database migration, version 4. This migration is backward compatible with any River installation running the v3 migration. Be sure to run the v4 migration prior to deploying the code from this release.
Add pending job state. This is currently unused, but will be used to build higher level functionality for staging jobs that are not yet ready to run (for some reason other than their scheduled time being in the future). Pending jobs will never be run or deleted and must first be moved to another state by external code. PR #301.
Queue status tracking, pause and resume. PR #301.
A useful operational lever is the ability to pause and resume a queue without shutting down clients. In addition to pause/resume being a feature request from #54, as part of the work on River's UI it's been useful to list out the active queues so that they can be displayed and manipulated.
A new river_queue table is introduced in the v4 migration for this purpose. Upon startup, every producer in each River Client will make an UPSERT query to the database to either register the queue as being active, or if it already exists it will instead bump the timestamp to keep it active. This query will be run periodically in each producer as long as the Client is alive, even if the queue is paused. A separate query will delete/purge any queues which have not been active in awhile (currently fixed to 24 hours).
QueuePause and QueueResume APIs have been introduced to Client pause and resume a single queue by name, or all queues using the special * value. Each producer will watch for notifications on the relevant LISTEN/NOTIFY topic unless operating in poll-only mode, in which case they will periodically poll for changes to their queue record in the database.
Job insert notifications are now handled within application code rather than within the database using triggers. PR #301.
The initial design for River utilized a trigger on job insert that issued notifications (NOTIFY) so that listening clients could quickly pick up the work if they were idle. While this is good for lowering latency, it does have the side effect of emitting a large amount of notifications any time there are lots of jobs being inserted. This adds overhead, particularly to high-throughput installations.
To improve this situation and reduce overhead in high-throughput installations, the notifications have been refactored to be emitted at the application level. A client-level debouncer ensures that these notifications are not emitted more often than they could be useful. If a queue is due for an insert notification (on a particular Postgres schema), the notification is piggy-backed onto the insert query within the transaction. While this has the impact of increasing insert latency for a certain percentage of cases, the effect should be small.
Additionally, initial releases of River did not properly scope notification topics within the global LISTEN/NOTIFY namespace. If two River installations were operating on the same Postgres database but within different schemas (search paths), their notifications would be emitted on a shared topic name. This is no longer the case and all notifications are prefixed with a {schema_name}. string.
Add NOT NULL constraints to the database for river_job.args and river_job.metadata. Normal code paths should never have allowed for null values any way, but this constraint further strengthens the guarantee. PR #301.
Stricter constraint on river_job.finalized_at to ensure it is only set when paired with a finalized state (completed, discarded, cancelled). Normal code paths should never have allowed for invalid values any way, but this constraint further strengthens the guarantee. PR #301.
./cmd/river and some documentation to rivertype. Thanks Danny Hermes (@dhermes)! 🙏🏻 PR #315.⚠️ Version 0.4.0 has a number of small breaking changes which we've decided to release all as part of a single version. More breaking changes in one release is inconvenient, but we've tried to coordinate them in hopes that any future breaking changes will be non-existent or very rare. All changes will get picked up by the Go compiler, and each one should be quite easy to fix. The changes don't apply to any of the most common core APIs, and likely many projects won't have to change any code.
JobList/JobListTx:
JobListOrderByID) instead of a job timestamp dependent on on requested job state. The previous ordering behavior is still available with NewJobListParams().OrderBy(JobListOrderByTime, SortOrderAsc). PR #307.JobListCursorFromJob no longer needs a sort order parameter. Instead, sort order is determined based on the job list parameters that the cursor is subsequently used with. PR #307.Insert and InsertTx functions now return a JobInsertResult struct instead of a JobRow. This allows the result to include metadata like the new UniqueSkippedAsDuplicate property, so callers can tell whether an inserted job was skipped due to unique constraint. PR #292.InsertMany and InsertManyTx now return number of jobs inserted as int instead of int64. This change was made to make the type in use a little more idiomatic. PR #293.river.JobState* type aliases have been removed. All job state constants should be accessed through rivertype.JobState* instead. PR #300.See also the 0.4.0 release blog post with code samples and rationale behind various changes.
Config.PollOnly which makes it avoid issuing LISTEN statements to wait for new events like a leadership resignation or new job available. The program instead polls periodically to look for changes. A leader resigning or a new job being available will be noticed less quickly, but PollOnly potentially makes River operable on systems without listen/notify support, like PgBouncer operating in transaction pooling mode. PR #281.rivertype.JobStates() that returns the full list of possible job states. PR #297.Client.PeriodicJobs().Add() and removed with Remove(). PR #288.info statements to debug so that info-level logging is overall less verbose. PR #275.Although it comes with a number of improvements, there's nothing particularly notable about version 0.1.0. Until now we've only been incrementing the patch version given the project's nascent nature, but from here on we'll try to adhere more closely to semantic versioning, using the patch version for bug fixes, and incrementing the minor version when new functionality is added.
river bench to benchmark River's job throughput against a database. PR #254.river migrate-get command to dump SQL for River migrations for use in alternative migration frameworks. Use it like river migrate-get --up --version 3 > version3.up.sql. PR #273.migrate-down and migrate-up options get two new options for --dry-run and --show-sql. They can be combined to easily run a preflight check on a River upgrade to see which migration commands would be run on a database, but without actually running them. PR #273.Client.SubscribeConfig function that lets a subscriber specify the maximum size of their subscription channel. PR #258.Config.ID. PR #255.riverpgxv5's Listener where it wouldn't unset an internal connection if Close returned an error, making the listener not reusable. Thanks @mfrister for pointing this one out! PR #246.JobListParams.Kinds() has been added so that jobs can now be listed by kind. PR #212.pgx/v5. This will allow additional drivers to be implemented, although there are no additional ones for now. PR #212.JobListParams.Queues() didn't filter correctly based on its arguments. PR #212.DebouncedChan where it would fire on its "out" channel too often when it was being signaled continuousy on its "in" channel. This would have caused work to be fetched more often than intended in busy systems. PR #222.