Allow common redis and leveldb connections (#12385)

* Allow common redis and leveldb connections

Prevents multiple reopening of redis and leveldb connections to the same
place by sharing connections.

Further allows for more configurable redis connection type using the
redisURI and a leveldbURI scheme.

Signed-off-by: Andrew Thornton <art27@cantab.net>

* add unit-test

Signed-off-by: Andrew Thornton <art27@cantab.net>

* as per @lunny

Signed-off-by: Andrew Thornton <art27@cantab.net>

* add test

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Update modules/cache/cache_redis.go

* Update modules/queue/queue_disk.go

* Update modules/cache/cache_redis.go

* Update modules/cache/cache_redis.go

* Update modules/queue/unique_queue_disk.go

* Update modules/queue/queue_disk.go

* Update modules/queue/unique_queue_disk.go

* Update modules/session/redis.go

Co-authored-by: techknowlogick <techknowlogick@gitea.io>
Co-authored-by: Lauris BH <lauris@nix.lv>

modules/queue/queue_disk.go

@@ -5,6 +5,8 @@
 package queue
 
 import (
+	"code.gitea.io/gitea/modules/nosql"
+
 	"gitea.com/lunny/levelqueue"
 )
 
@@ -14,7 +16,9 @@ const LevelQueueType Type = "level"
 // LevelQueueConfiguration is the configuration for a LevelQueue
 type LevelQueueConfiguration struct {
 	ByteFIFOQueueConfiguration
-	DataDir string
+	DataDir          string
+	ConnectionString string
+	QueueName        string
 }
 
 // LevelQueue implements a disk library queue
@@ -30,7 +34,11 @@ func NewLevelQueue(handle HandlerFunc, cfg, exemplar interface{}) (Queue, error)
 	}
 	config := configInterface.(LevelQueueConfiguration)
 
-	byteFIFO, err := NewLevelQueueByteFIFO(config.DataDir)
+	if len(config.ConnectionString) == 0 {
+		config.ConnectionString = config.DataDir
+	}
+
+	byteFIFO, err := NewLevelQueueByteFIFO(config.ConnectionString, config.QueueName)
 	if err != nil {
 		return nil, err
 	}
@@ -51,18 +59,25 @@ var _ (ByteFIFO) = &LevelQueueByteFIFO{}
 
 // LevelQueueByteFIFO represents a ByteFIFO formed from a LevelQueue
 type LevelQueueByteFIFO struct {
-	internal *levelqueue.Queue
+	internal   *levelqueue.Queue
+	connection string
 }
 
 // NewLevelQueueByteFIFO creates a ByteFIFO formed from a LevelQueue
-func NewLevelQueueByteFIFO(dataDir string) (*LevelQueueByteFIFO, error) {
-	internal, err := levelqueue.Open(dataDir)
+func NewLevelQueueByteFIFO(connection, prefix string) (*LevelQueueByteFIFO, error) {
+	db, err := nosql.GetManager().GetLevelDB(connection)
+	if err != nil {
+		return nil, err
+	}
+
+	internal, err := levelqueue.NewQueue(db, []byte(prefix), false)
 	if err != nil {
 		return nil, err
 	}
 
 	return &LevelQueueByteFIFO{
-		internal: internal,
+		connection: connection,
+		internal:   internal,
 	}, nil
 }
 
@@ -87,7 +102,9 @@ func (fifo *LevelQueueByteFIFO) Pop() ([]byte, error) {
 
 // Close this fifo
 func (fifo *LevelQueueByteFIFO) Close() error {
-	return fifo.internal.Close()
+	err := fifo.internal.Close()
+	_ = nosql.GetManager().CloseLevelDB(fifo.connection)
+	return err
 }
 
 // Len returns the length of the fifo