Merge pull request #12680 from svenklemm/timebucket

[postgres] add timescaledb option to postgres datasource

docs/sources/features/datasources/postgres.md

@@ -31,6 +31,7 @@ Name | Description
 *User* | Database user's login/username
 *Password* | Database user's password
 *SSL Mode* | This option determines whether or with what priority a secure SSL TCP/IP connection will be negotiated with the server.
+*TimescaleDB* | With this option enabled Grafana will use TimescaleDB features, e.g. use ```time_bucket``` for grouping by time (only available in Grafana 5.3+).
 
 ### Database User Permissions (Important!)
 
@@ -289,4 +290,5 @@ datasources:
       password: "Password!"
     jsonData:
       sslmode: "disable" # disable/require/verify-ca/verify-full
+      timescaledb: false
 ```

pkg/tsdb/postgres/macros.go

@@ -16,10 +16,11 @@ const sExpr = `\$` + rsIdentifier + `\(([^\)]*)\)`
 type postgresMacroEngine struct {
 	timeRange   *tsdb.TimeRange
 	query       *tsdb.Query
+	timescaledb bool
 }
 
-func newPostgresMacroEngine() tsdb.SqlMacroEngine {
-	return &postgresMacroEngine{}
+func newPostgresMacroEngine(timescaledb bool) tsdb.SqlMacroEngine {
+	return &postgresMacroEngine{timescaledb: timescaledb}
 }
 
 func (m *postgresMacroEngine) Interpolate(query *tsdb.Query, timeRange *tsdb.TimeRange, sql string) (string, error) {
@@ -118,7 +119,12 @@ func (m *postgresMacroEngine) evaluateMacro(name string, args []string) (string,
 				return "", err
 			}
 		}
+
+		if m.timescaledb {
+			return fmt.Sprintf("time_bucket('%vs',%s)", interval.Seconds(), args[0]), nil
+		} else {
 			return fmt.Sprintf("floor(extract(epoch from %s)/%v)*%v", args[0], interval.Seconds(), interval.Seconds()), nil
+		}
 	case "__timeGroupAlias":
 		tg, err := m.evaluateMacro("__timeGroup", args)
 		if err == nil {

pkg/tsdb/postgres/macros_test.go

@@ -12,7 +12,10 @@ import (
 
 func TestMacroEngine(t *testing.T) {
 	Convey("MacroEngine", t, func() {
-		engine := newPostgresMacroEngine()
+		timescaledbEnabled := false
+		engine := newPostgresMacroEngine(timescaledbEnabled)
+		timescaledbEnabled = true
+		engineTS := newPostgresMacroEngine(timescaledbEnabled)
 		query := &tsdb.Query{}
 
 		Convey("Given a time range between 2018-04-12 00:00 and 2018-04-12 00:05", func() {
@@ -83,6 +86,22 @@ func TestMacroEngine(t *testing.T) {
 				So(sql2, ShouldEqual, sql+" AS \"time\"")
 			})
 
+			Convey("interpolate __timeGroup function with TimescaleDB enabled", func() {
+
+				sql, err := engineTS.Interpolate(query, timeRange, "GROUP BY $__timeGroup(time_column,'5m')")
+				So(err, ShouldBeNil)
+
+				So(sql, ShouldEqual, "GROUP BY time_bucket('300s',time_column)")
+			})
+
+			Convey("interpolate __timeGroup function with spaces between args and TimescaleDB enabled", func() {
+
+				sql, err := engineTS.Interpolate(query, timeRange, "GROUP BY $__timeGroup(time_column , '5m')")
+				So(err, ShouldBeNil)
+
+				So(sql, ShouldEqual, "GROUP BY time_bucket('300s',time_column)")
+			})
+
 			Convey("interpolate __timeTo function", func() {
 				sql, err := engine.Interpolate(query, timeRange, "select $__timeTo(time_column)")
 				So(err, ShouldBeNil)

pkg/tsdb/postgres/postgres.go

@@ -32,7 +32,9 @@ func newPostgresQueryEndpoint(datasource *models.DataSource) (tsdb.TsdbQueryEndp
 		log: logger,
 	}
 
-	return tsdb.NewSqlQueryEndpoint(&config, &rowTransformer, newPostgresMacroEngine(), logger)
+	timescaledb := datasource.JsonData.Get("timescaledb").MustBool(false)
+
+	return tsdb.NewSqlQueryEndpoint(&config, &rowTransformer, newPostgresMacroEngine(timescaledb), logger)
 }
 
 func generateConnectionString(datasource *models.DataSource) string {

pkg/tsdb/postgres/postgres_test.go

@@ -27,7 +27,7 @@ import (
 // use to verify that the generated data are vizualized as expected, see
 // devenv/README.md for setup instructions.
 func TestPostgres(t *testing.T) {
-	// change to true to run the MySQL tests
+	// change to true to run the PostgreSQL tests
 	runPostgresTests := false
 	// runPostgresTests := true
 

public/app/plugins/datasource/postgres/datasource.ts

@@ -124,25 +124,7 @@ export class PostgresDatasource {
   }
 
   testDatasource() {
-    return this.backendSrv
-      .datasourceRequest({
-        url: '/api/tsdb/query',
-        method: 'POST',
-        data: {
-          from: '5m',
-          to: 'now',
-          queries: [
-            {
-              refId: 'A',
-              intervalMs: 1,
-              maxDataPoints: 1,
-              datasourceId: this.id,
-              rawSql: 'SELECT 1',
-              format: 'table',
-            },
-          ],
-        },
-      })
+    return this.metricFindQuery('SELECT 1', {})
       .then(res => {
         return { status: 'success', message: 'Database Connection OK' };
       })

public/app/plugins/datasource/postgres/partials/config.html

@@ -38,6 +38,14 @@
 	</div>
 </div>
 
+<h3 class="page-heading">PostgreSQL details</h3>
+
+<div class="gf-form-group">
+	<div class="gf-form">
+		<gf-form-switch class="gf-form" label="TimescaleDB" tooltip="Use TimescaleDB features (e.g., time_bucket) in Grafana" label-class="width-9" checked="ctrl.current.jsonData.timescaledb" switch-class="max-width-6"></gf-form-switch>
+	</div>
+</div>
+
 <div class="gf-form-group">
 	<div class="grafana-info-box">
 		<h5>User Permission</h5>