Graceful Queues: Issue Indexing and Tasks (#9363)

* Queue: Add generic graceful queues with settings

* Queue & Setting: Add worker pool implementation

* Queue: Add worker settings

* Queue: Make resizing worker pools

* Queue: Add name variable to queues

* Queue: Add monitoring

* Queue: Improve logging

* Issues: Gracefulise the issues indexer

Remove the old now unused specific queues

* Task: Move to generic queue and gracefulise

* Issues: Standardise the issues indexer queue settings

* Fix test

* Queue: Allow Redis to connect to unix

* Prevent deadlock during early shutdown of issue indexer

* Add MaxWorker settings to queues

* Merge branch 'master' into graceful-queues

* Update modules/indexer/issues/indexer.go

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

* Update modules/indexer/issues/indexer.go

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

* Update modules/queue/queue_channel.go

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

* Update modules/queue/queue_disk.go

* Update modules/queue/queue_disk_channel.go

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

* Rename queue.Description to queue.ManagedQueue as per @guillep2k

* Cancel pool workers when removed

* Remove dependency on queue from setting

* Update modules/queue/queue_redis.go

Co-Authored-By: guillep2k <18600385+guillep2k@users.noreply.github.com>

* As per @guillep2k add mutex locks on shutdown/terminate

* move unlocking out of setInternal

* Add warning if number of workers < 0

* Small changes as per @guillep2k

* No redis host specified not found

* Clean up documentation for queues

* Update docs/content/doc/advanced/config-cheat-sheet.en-us.md

* Update modules/indexer/issues/indexer_test.go

* Ensure that persistable channel queue is added to manager

* Rename QUEUE_NAME REDIS_QUEUE_NAME

* Revert "Rename QUEUE_NAME REDIS_QUEUE_NAME"

This reverts commit 1f83b4fc9b.

Co-authored-by: guillep2k <18600385+guillep2k@users.noreply.github.com>
Co-authored-by: Lauris BH <lauris@nix.lv>
Co-authored-by: techknowlogick <matti@mdranta.net>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

modules/queue/queue_disk_channel_test.go

@@ -0,0 +1,117 @@
+// Copyright 2019 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package queue
+
+import (
+	"context"
+	"io/ioutil"
+	"os"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPersistableChannelQueue(t *testing.T) {
+	handleChan := make(chan *testData)
+	handle := func(data ...Data) {
+		assert.True(t, len(data) == 2)
+		for _, datum := range data {
+			testDatum := datum.(*testData)
+			handleChan <- testDatum
+		}
+	}
+
+	queueShutdown := []func(){}
+	queueTerminate := []func(){}
+
+	tmpDir, err := ioutil.TempDir("", "persistable-channel-queue-test-data")
+	assert.NoError(t, err)
+	defer os.RemoveAll(tmpDir)
+
+	queue, err := NewPersistableChannelQueue(handle, PersistableChannelQueueConfiguration{
+		DataDir:     tmpDir,
+		BatchLength: 2,
+		QueueLength: 20,
+		Workers:     1,
+		MaxWorkers:  10,
+	}, &testData{})
+	assert.NoError(t, err)
+
+	go queue.Run(func(_ context.Context, shutdown func()) {
+		queueShutdown = append(queueShutdown, shutdown)
+	}, func(_ context.Context, terminate func()) {
+		queueTerminate = append(queueTerminate, terminate)
+	})
+
+	test1 := testData{"A", 1}
+	test2 := testData{"B", 2}
+
+	err = queue.Push(&test1)
+	assert.NoError(t, err)
+	go func() {
+		err = queue.Push(&test2)
+		assert.NoError(t, err)
+	}()
+
+	result1 := <-handleChan
+	assert.Equal(t, test1.TestString, result1.TestString)
+	assert.Equal(t, test1.TestInt, result1.TestInt)
+
+	result2 := <-handleChan
+	assert.Equal(t, test2.TestString, result2.TestString)
+	assert.Equal(t, test2.TestInt, result2.TestInt)
+
+	err = queue.Push(test1)
+	assert.Error(t, err)
+
+	for _, callback := range queueShutdown {
+		callback()
+	}
+	time.Sleep(200 * time.Millisecond)
+	err = queue.Push(&test1)
+	assert.NoError(t, err)
+	err = queue.Push(&test2)
+	assert.NoError(t, err)
+	select {
+	case <-handleChan:
+		assert.Fail(t, "Handler processing should have stopped")
+	default:
+	}
+	for _, callback := range queueTerminate {
+		callback()
+	}
+
+	// Reopen queue
+	queue, err = NewPersistableChannelQueue(handle, PersistableChannelQueueConfiguration{
+		DataDir:     tmpDir,
+		BatchLength: 2,
+		QueueLength: 20,
+		Workers:     1,
+		MaxWorkers:  10,
+	}, &testData{})
+	assert.NoError(t, err)
+
+	go queue.Run(func(_ context.Context, shutdown func()) {
+		queueShutdown = append(queueShutdown, shutdown)
+	}, func(_ context.Context, terminate func()) {
+		queueTerminate = append(queueTerminate, terminate)
+	})
+
+	result3 := <-handleChan
+	assert.Equal(t, test1.TestString, result3.TestString)
+	assert.Equal(t, test1.TestInt, result3.TestInt)
+
+	result4 := <-handleChan
+	assert.Equal(t, test2.TestString, result4.TestString)
+	assert.Equal(t, test2.TestInt, result4.TestInt)
+	for _, callback := range queueShutdown {
+		callback()
+	}
+	for _, callback := range queueTerminate {
+		callback()
+	}
+
+}