fix replication DB connection issue

fixes #15736

For the current imple, the GetWorker() may hang when there is no worker available, and will not release the DB connection.
In this case, the DB connection could reach the up limit that leads to harbor core for service unavailable.

1, move GetWorker() in the goroutine, release the DB connection for API.
2, reduce the worker count per harbor-core from 1024 to 10.
3, reduce the runner count per worker to 30.

After above, the max connection per harbor-core should be 300.

Worker: To control how many replicaiton exectuions can have at most at the same time.
Runner: To control the speed to generate an jobservice replicaiton job.

Signed-off-by: Wang Yan <wangyan@vmware.com>

src/controller/replication/execution.go

@@ -87,7 +87,7 @@ func NewController() Controller {
 		scheduler:  scheduler.Sched,
 		flowCtl:    flow.NewController(),
 		ormCreator: orm.Crt,
-		wp:         lib.NewWorkerPool(1024),
+		wp:         lib.NewWorkerPool(10),
 	}
 }
 
@@ -113,13 +113,15 @@ func (c *controller) Start(ctx context.Context, policy *replicationmodel.Policy,
 	if err != nil {
 		return 0, err
 	}
-	c.wp.GetWorker()
 	// start the replication flow in background
 	// as the process runs inside a goroutine, the transaction in the outer ctx
-	// may be submitted already when the process starts, so pass a new context
+	// may be submitted already when the process starts, so create an new context
 	// with orm populated to the goroutine
-	go func(ctx context.Context) {
+	go func() {
+		c.wp.GetWorker()
 		defer c.wp.ReleaseWorker()
+
+		ctx := orm.NewContext(context.Background(), c.ormCreator.Create())
 		// recover in case panic during the adapter process
 		defer func() {
 			if err := recover(); err != nil {
@@ -145,7 +147,7 @@ func (c *controller) Start(ctx context.Context, policy *replicationmodel.Policy,
 			return
 		}
 		c.markError(ctx, id, err)
-	}(orm.NewContext(context.Background(), c.ormCreator.Create()))
+	}()
 	return id, nil
 }
 

src/pkg/reg/adapter/adapter.go

@@ -26,7 +26,7 @@ import (
 
 // const definition
 const (
-	MaxConcurrency = 100
+	MaxConcurrency = 30
 )
 
 var registry = map[string]Factory{}