Implement graceful shutdown of agent.DataAccess (#1008)

* Implements graceful shutdown of agent.DataAccess and underlying Datastore/Logstore/MessageQueue

* adds tests for closing agent.DataAccess and Datastore

api/mqs/bolt.go

@@ -347,3 +347,10 @@ func (mq *BoltDbMQ) Delete(ctx context.Context, job *models.Call) error {
 		return nil
 	})
 }
+
+// Close shuts down the bolt db connection and
+// stops the goroutine associated with the ticker
+func (mq *BoltDbMQ) Close() error {
+	mq.ticker.Stop()
+	return mq.db.Close()
+}

api/mqs/memory.go

@@ -192,3 +192,9 @@ func (mq *MemoryMQ) Delete(ctx context.Context, job *models.Call) error {
 	log.Debugln("Deleted")
 	return nil
 }
+
+// Close stops the associated goroutines by stopping the ticker
+func (mq *MemoryMQ) Close() error {
+	mq.Ticker.Stop()
+	return nil
+}

api/mqs/mock.go

@@ -24,3 +24,7 @@ func (mock *Mock) Reserve(context.Context) (*models.Call, error) {
 func (mock *Mock) Delete(context.Context, *models.Call) error {
 	return nil
 }
+
+func (mock *Mock) Close() error {
+	return nil
+}

api/mqs/new.go

@@ -60,3 +60,8 @@ func (m *metricMQ) Delete(ctx context.Context, t *models.Call) error {
 	defer span.End()
 	return m.mq.Delete(ctx, t)
 }
+
+// Close closes the underlying message queue
+func (m *metricMQ) Close() error {
+	return m.mq.Close()
+}

api/mqs/redis.go

@@ -307,3 +307,10 @@ func (mq *RedisMQ) Delete(ctx context.Context, job *models.Call) error {
 	_, err = conn.Do("HDEL", "timeout", resID)
 	return err
 }
+
+// Close shuts down the redis connection pool and
+// stops the goroutine associated with the ticker
+func (mq *RedisMQ) Close() error {
+	mq.ticker.Stop()
+	return mq.pool.Close()
+}