grafana/pkg/expr/service.go
Yuriy Tseretyan 2d20c8db7b
Chore: Expression engine to support relative time range (#57474)
* make TimeRange interface and add relative range
* make Execute methods support the current time
* update resample to support relative time range
* update DSNode to support relative time range
* update query service to create queries with absolute time
* make alerting evaluator create relative time ranges
2022-10-26 16:13:58 -04:00

90 lines
2.8 KiB
Go

package expr
import (
"context"
"time"
"github.com/grafana/grafana-plugin-sdk-go/backend"
"github.com/grafana/grafana/pkg/components/simplejson"
"github.com/grafana/grafana/pkg/plugins"
"github.com/grafana/grafana/pkg/services/datasources"
"github.com/grafana/grafana/pkg/setting"
)
// DatasourceType is the string constant used as the datasource when the property is in Datasource.Type.
// Type in requests is used to identify what type of data source plugin the request belongs to.
const DatasourceType = "__expr__"
// DatasourceUID is the string constant used as the datasource name in requests
// to identify it as an expression command when use in Datasource.UID.
const DatasourceUID = DatasourceType
// DatasourceID is the fake datasource id used in requests to identify it as an
// expression command.
const DatasourceID = -100
// OldDatasourceUID is the datasource uid used in requests to identify it as an
// expression command. It goes with the query root level datasourceUID property. It was accidentally
// set to the Id and is now kept for backwards compatibility. The newer Datasource.UID property
// should be used instead and should be set to "__expr__".
const OldDatasourceUID = "-100"
// IsDataSource checks if the uid points to an expression query
func IsDataSource(uid string) bool {
return uid == DatasourceUID || uid == OldDatasourceUID
}
// Service is service representation for expression handling.
type Service struct {
cfg *setting.Cfg
dataService backend.QueryDataHandler
dataSourceService datasources.DataSourceService
}
func ProvideService(cfg *setting.Cfg, pluginClient plugins.Client, dataSourceService datasources.DataSourceService) *Service {
return &Service{
cfg: cfg,
dataService: pluginClient,
dataSourceService: dataSourceService,
}
}
func (s *Service) isDisabled() bool {
if s.cfg == nil {
return true
}
return !s.cfg.ExpressionsEnabled
}
// BuildPipeline builds a pipeline from a request.
func (s *Service) BuildPipeline(req *Request) (DataPipeline, error) {
return s.buildPipeline(req)
}
// ExecutePipeline executes an expression pipeline and returns all the results.
func (s *Service) ExecutePipeline(ctx context.Context, now time.Time, pipeline DataPipeline) (*backend.QueryDataResponse, error) {
res := backend.NewQueryDataResponse()
vars, err := pipeline.execute(ctx, now, s)
if err != nil {
return nil, err
}
for refID, val := range vars {
res.Responses[refID] = backend.DataResponse{
Frames: val.Values.AsDataFrames(refID),
}
}
return res, nil
}
func DataSourceModel() *datasources.DataSource {
return &datasources.DataSource{
Id: DatasourceID,
Uid: DatasourceUID,
Name: DatasourceUID,
Type: DatasourceType,
JsonData: simplejson.New(),
SecureJsonData: make(map[string][]byte),
}
}