From 6f9c278559789066aa831c1df25b0d866103d02d Mon Sep 17 00:00:00 2001 From: wxiaoguang Date: Mon, 8 May 2023 19:49:59 +0800 Subject: Rewrite queue (#24505) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit # ⚠️ Breaking Many deprecated queue config options are removed (actually, they should have been removed in 1.18/1.19). If you see the fatal message when starting Gitea: "Please update your app.ini to remove deprecated config options", please follow the error messages to remove these options from your app.ini. Example: ``` 2023/05/06 19:39:22 [E] Removed queue option: `[indexer].ISSUE_INDEXER_QUEUE_TYPE`. Use new options in `[queue.issue_indexer]` 2023/05/06 19:39:22 [E] Removed queue option: `[indexer].UPDATE_BUFFER_LEN`. Use new options in `[queue.issue_indexer]` 2023/05/06 19:39:22 [F] Please update your app.ini to remove deprecated config options ``` Many options in `[queue]` are are dropped, including: `WRAP_IF_NECESSARY`, `MAX_ATTEMPTS`, `TIMEOUT`, `WORKERS`, `BLOCK_TIMEOUT`, `BOOST_TIMEOUT`, `BOOST_WORKERS`, they can be removed from app.ini. # The problem The old queue package has some legacy problems: * complexity: I doubt few people could tell how it works. * maintainability: Too many channels and mutex/cond are mixed together, too many different structs/interfaces depends each other. * stability: due to the complexity & maintainability, sometimes there are strange bugs and difficult to debug, and some code doesn't have test (indeed some code is difficult to test because a lot of things are mixed together). * general applicability: although it is called "queue", its behavior is not a well-known queue. * scalability: it doesn't seem easy to make it work with a cluster without breaking its behaviors. It came from some very old code to "avoid breaking", however, its technical debt is too heavy now. It's a good time to introduce a better "queue" package. # The new queue package It keeps using old config and concept as much as possible. * It only contains two major kinds of concepts: * The "base queue": channel, levelqueue, redis * They have the same abstraction, the same interface, and they are tested by the same testing code. * The "WokerPoolQueue", it uses the "base queue" to provide "worker pool" function, calls the "handler" to process the data in the base queue. * The new code doesn't do "PushBack" * Think about a queue with many workers, the "PushBack" can't guarantee the order for re-queued unhandled items, so in new code it just does "normal push" * The new code doesn't do "pause/resume" * The "pause/resume" was designed to handle some handler's failure: eg: document indexer (elasticsearch) is down * If a queue is paused for long time, either the producers blocks or the new items are dropped. * The new code doesn't do such "pause/resume" trick, it's not a common queue's behavior and it doesn't help much. * If there are unhandled items, the "push" function just blocks for a few seconds and then re-queue them and retry. * The new code doesn't do "worker booster" * Gitea's queue's handlers are light functions, the cost is only the go-routine, so it doesn't make sense to "boost" them. * The new code only use "max worker number" to limit the concurrent workers. * The new "Push" never blocks forever * Instead of creating more and more blocking goroutines, return an error is more friendly to the server and to the end user. There are more details in code comments: eg: the "Flush" problem, the strange "code.index" hanging problem, the "immediate" queue problem. Almost ready for review. TODO: * [x] add some necessary comments during review * [x] add some more tests if necessary * [x] update documents and config options * [x] test max worker / active worker * [x] re-run the CI tasks to see whether any test is flaky * [x] improve the `handleOldLengthConfiguration` to provide more friendly messages * [x] fine tune default config values (eg: length?) ## Code coverage: ![image](https://user-images.githubusercontent.com/2114189/236620635-55576955-f95d-4810-b12f-879026a3afdf.png) --- services/task/task.go | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) (limited to 'services/task') diff --git a/services/task/task.go b/services/task/task.go index 41bc07f2f6..4f1ba3a60b 100644 --- a/services/task/task.go +++ b/services/task/task.go @@ -23,7 +23,7 @@ import ( ) // taskQueue is a global queue of tasks -var taskQueue queue.Queue +var taskQueue *queue.WorkerPoolQueue[*admin_model.Task] // Run a task func Run(t *admin_model.Task) error { @@ -37,7 +37,7 @@ func Run(t *admin_model.Task) error { // Init will start the service to get all unfinished tasks and run them func Init() error { - taskQueue = queue.CreateQueue("task", handle, &admin_model.Task{}) + taskQueue = queue.CreateSimpleQueue("task", handler) if taskQueue == nil { return fmt.Errorf("Unable to create Task Queue") @@ -48,9 +48,8 @@ func Init() error { return nil } -func handle(data ...queue.Data) []queue.Data { - for _, datum := range data { - task := datum.(*admin_model.Task) +func handler(items ...*admin_model.Task) []*admin_model.Task { + for _, task := range items { if err := Run(task); err != nil { log.Error("Run task failed: %v", err) } -- cgit v1.2.3