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_test.go

@@ -0,0 +1,43 @@
+// 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 (
+	"encoding/json"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type testData struct {
+	TestString string
+	TestInt    int
+}
+
+func TestToConfig(t *testing.T) {
+	cfg := testData{
+		TestString: "Config",
+		TestInt:    10,
+	}
+	exemplar := testData{}
+
+	cfg2I, err := toConfig(exemplar, cfg)
+	assert.NoError(t, err)
+	cfg2, ok := (cfg2I).(testData)
+	assert.True(t, ok)
+	assert.NotEqual(t, cfg2, exemplar)
+	assert.Equal(t, &cfg, &cfg2)
+
+	cfgString, err := json.Marshal(cfg)
+	assert.NoError(t, err)
+
+	cfg3I, err := toConfig(exemplar, cfgString)
+	assert.NoError(t, err)
+	cfg3, ok := (cfg3I).(testData)
+	assert.True(t, ok)
+	assert.Equal(t, cfg.TestString, cfg3.TestString)
+	assert.Equal(t, cfg.TestInt, cfg3.TestInt)
+	assert.NotEqual(t, cfg3, exemplar)
+}