mysql: fix dispose-method not called in external-mode (#87330)

pkg/tsdb/mysql/mysql.go

@@ -31,24 +31,11 @@ const (
 	dateTimeFormat2 = "2006-01-02T15:04:05Z"
 )
 
-type Service struct {
-	im     instancemgmt.InstanceManager
-	logger log.Logger
-}
-
 func characterEscape(s string, escapeChar string) string {
 	return strings.ReplaceAll(s, escapeChar, url.QueryEscape(escapeChar))
 }
 
-func ProvideService() *Service {
+func NewInstanceSettings(logger log.Logger) datasource.InstanceFactoryFunc {
-	logger := backend.NewLoggerWith("logger", "tsdb.mysql")
-	return &Service{
-		im:     datasource.NewInstanceManager(newInstanceSettings(logger)),
-		logger: logger,
-	}
-}
-
-func newInstanceSettings(logger log.Logger) datasource.InstanceFactoryFunc {
 	return func(ctx context.Context, settings backend.DataSourceInstanceSettings) (instancemgmt.Instance, error) {
 		cfg := backend.GrafanaConfigFromContext(ctx)
 		sqlCfg, err := cfg.SQL()
@@ -171,42 +158,6 @@ func newInstanceSettings(logger log.Logger) datasource.InstanceFactoryFunc {
 	}
 }
 
-func (s *Service) getDataSourceHandler(ctx context.Context, pluginCtx backend.PluginContext) (*sqleng.DataSourceHandler, error) {
-	i, err := s.im.Get(ctx, pluginCtx)
-	if err != nil {
-		return nil, err
-	}
-	instance := i.(*sqleng.DataSourceHandler)
-	return instance, nil
-}
-
-// CheckHealth pings the connected SQL database
-func (s *Service) CheckHealth(ctx context.Context, req *backend.CheckHealthRequest) (*backend.CheckHealthResult, error) {
-	dsHandler, err := s.getDataSourceHandler(ctx, req.PluginContext)
-	if err != nil {
-		return nil, err
-	}
-
-	err = dsHandler.Ping()
-
-	if err != nil {
-		var driverErr *mysql.MySQLError
-		if errors.As(err, &driverErr) {
-			return &backend.CheckHealthResult{Status: backend.HealthStatusError, Message: dsHandler.TransformQueryError(s.logger, driverErr).Error()}, nil
-		}
-		return &backend.CheckHealthResult{Status: backend.HealthStatusError, Message: dsHandler.TransformQueryError(s.logger, err).Error()}, nil
-	}
-	return &backend.CheckHealthResult{Status: backend.HealthStatusOk, Message: "Database Connection OK"}, nil
-}
-
-func (s *Service) QueryData(ctx context.Context, req *backend.QueryDataRequest) (*backend.QueryDataResponse, error) {
-	dsHandler, err := s.getDataSourceHandler(ctx, req.PluginContext)
-	if err != nil {
-		return nil, err
-	}
-	return dsHandler.QueryData(ctx, req)
-}
-
 type mysqlQueryResultTransformer struct {
 	userError string
 }

pkg/tsdb/mysql/mysql_service.go

@@ -0,0 +1,53 @@
+package mysql
+
+import (
+	"context"
+
+	"github.com/grafana/grafana-plugin-sdk-go/backend"
+	"github.com/grafana/grafana-plugin-sdk-go/backend/datasource"
+	"github.com/grafana/grafana-plugin-sdk-go/backend/instancemgmt"
+
+	"github.com/grafana/grafana-plugin-sdk-go/backend/log"
+	"github.com/grafana/grafana/pkg/tsdb/mysql/sqleng"
+)
+
+type Service struct {
+	im     instancemgmt.InstanceManager
+	logger log.Logger
+}
+
+func ProvideService() *Service {
+	logger := backend.NewLoggerWith("logger", "tsdb.mysql")
+	return &Service{
+		im:     datasource.NewInstanceManager(NewInstanceSettings(logger)),
+		logger: logger,
+	}
+}
+
+func (s *Service) getDataSourceHandler(ctx context.Context, pluginCtx backend.PluginContext) (*sqleng.DataSourceHandler, error) {
+	i, err := s.im.Get(ctx, pluginCtx)
+	if err != nil {
+		return nil, err
+	}
+	instance := i.(*sqleng.DataSourceHandler)
+	return instance, nil
+}
+
+// NOTE: do not put any business logic into this method. it's whole job is to forward the call "inside"
+func (s *Service) CheckHealth(ctx context.Context, req *backend.CheckHealthRequest) (*backend.CheckHealthResult, error) {
+	dsHandler, err := s.getDataSourceHandler(ctx, req.PluginContext)
+	if err != nil {
+		return nil, err
+	}
+
+	return dsHandler.CheckHealth(ctx, req)
+}
+
+// NOTE: do not put any business logic into this method. it's whole job is to forward the call "inside"
+func (s *Service) QueryData(ctx context.Context, req *backend.QueryDataRequest) (*backend.QueryDataResponse, error) {
+	dsHandler, err := s.getDataSourceHandler(ctx, req.PluginContext)
+	if err != nil {
+		return nil, err
+	}
+	return dsHandler.QueryData(ctx, req)
+}

pkg/tsdb/mysql/sqleng/sql_engine.go

@@ -14,6 +14,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/go-sql-driver/mysql"
 	"github.com/grafana/grafana-plugin-sdk-go/backend"
 	"github.com/grafana/grafana-plugin-sdk-go/data"
 	"github.com/grafana/grafana-plugin-sdk-go/data/sqlutil"
@@ -153,8 +154,17 @@ func (e *DataSourceHandler) Dispose() {
 	e.log.Debug("DB disposed")
 }
 
-func (e *DataSourceHandler) Ping() error {
+func (e *DataSourceHandler) CheckHealth(ctx context.Context, req *backend.CheckHealthRequest) (*backend.CheckHealthResult, error) {
-	return e.db.Ping()
+	err := e.db.Ping()
+
+	if err != nil {
+		var driverErr *mysql.MySQLError
+		if errors.As(err, &driverErr) {
+			return &backend.CheckHealthResult{Status: backend.HealthStatusError, Message: e.TransformQueryError(e.log, driverErr).Error()}, nil
+		}
+		return &backend.CheckHealthResult{Status: backend.HealthStatusError, Message: e.TransformQueryError(e.log, err).Error()}, nil
+	}
+	return &backend.CheckHealthResult{Status: backend.HealthStatusOk, Message: "Database Connection OK"}, nil
 }
 
 func (e *DataSourceHandler) QueryData(ctx context.Context, req *backend.QueryDataRequest) (*backend.QueryDataResponse, error) {

pkg/tsdb/mysql/standalone/datasource.go

@@ -1,32 +0,0 @@
-package main
-
-import (
-	"context"
-
-	"github.com/grafana/grafana-plugin-sdk-go/backend"
-	"github.com/grafana/grafana-plugin-sdk-go/backend/instancemgmt"
-	mysqlds "github.com/grafana/grafana/pkg/tsdb/mysql"
-)
-
-var (
-	_ backend.QueryDataHandler   = (*Datasource)(nil)
-	_ backend.CheckHealthHandler = (*Datasource)(nil)
-)
-
-func NewDatasource(context.Context, backend.DataSourceInstanceSettings) (instancemgmt.Instance, error) {
-	return &Datasource{
-		Service: mysqlds.ProvideService(),
-	}, nil
-}
-
-type Datasource struct {
-	Service *mysqlds.Service
-}
-
-func (d *Datasource) QueryData(ctx context.Context, req *backend.QueryDataRequest) (*backend.QueryDataResponse, error) {
-	return d.Service.QueryData(ctx, req)
-}
-
-func (d *Datasource) CheckHealth(ctx context.Context, req *backend.CheckHealthRequest) (*backend.CheckHealthResult, error) {
-	return d.Service.CheckHealth(ctx, req)
-}

pkg/tsdb/mysql/standalone/main.go

@@ -3,8 +3,10 @@ package main
 import (
 	"os"
 
+	"github.com/grafana/grafana-plugin-sdk-go/backend"
 	"github.com/grafana/grafana-plugin-sdk-go/backend/datasource"
 	"github.com/grafana/grafana-plugin-sdk-go/backend/log"
+	"github.com/grafana/grafana/pkg/tsdb/mysql"
 )
 
 func main() {
@@ -16,7 +18,8 @@ func main() {
 	// from Grafana to create different instances of SampleDatasource (per datasource
 	// ID). When datasource configuration changed Dispose method will be called and
 	// new datasource instance created using NewSampleDatasource factory.
-	if err := datasource.Manage("mysql", NewDatasource, datasource.ManageOpts{}); err != nil {
+	logger := backend.NewLoggerWith("logger", "tsdb.mysql")
+	if err := datasource.Manage("mysql", mysql.NewInstanceSettings(logger), datasource.ManageOpts{}); err != nil {
 		log.DefaultLogger.Error(err.Error())
 		os.Exit(1)
 	}