fix: Fix a memory leak in monitor module

Signed-off-by: Utkarsh Saxena <[email protected]>

internal/monitor/core.go

@@ -168,6 +168,7 @@ func (c *Core) isBackendUp(ctx *context.Context, b *gatewayv1.Backend) (bool, er
 		user: boot.Config.Monitor.Trino.User,
 		url:  url.URL{Scheme: b.GetScheme().Enum().String(), Host: b.GetHostname()},
 	}
+	defer trinoClient.Teardown(ctx)
 	isUp, err := trinoClient.IsClusterUp(ctx)
 	if err != nil {
 		provider.Logger(*ctx).WithError(err).Errorw(
@@ -220,6 +221,7 @@ func (c *Core) getBackendLoad(ctx *context.Context, b *gatewayv1.Backend) (int32
 		url:  url.URL{Scheme: b.GetScheme().Enum().String(), Host: b.GetHostname()},
 		pass: boot.Config.Monitor.Trino.Password,
 	}
+	defer trinoClient.Teardown(ctx)
 
 	type StateStat struct {
 		state string

internal/monitor/trino.go

@@ -20,6 +20,7 @@ import (
 type ITrinoClient interface {
 	IsClusterUp(ctx *context.Context) (bool, error)
 	RunQuery(ctx *context.Context, query string) (*sql.Rows, error)
+	Teardown(ctx *context.Context) error
 }
 
 type TrinoClient struct {
@@ -222,3 +223,17 @@ func (t *TrinoClient) RunQuery(ctx *context.Context, q string) (*sql.Rows, error
 
 	return rows, nil
 }
+
+func (t *TrinoClient) Teardown(ctx *context.Context) error {
+	if t.db != nil {
+		// log
+		err := t.db.Close()
+		if err != nil {
+			provider.Logger(*ctx).WithError(err).Errorw(
+				"error closing trino db client",
+				map[string]interface{}{"trinoHost": t.url.Host})
+			return err
+		}
+	}
+	return nil
+}