Merge pull request #153 from K-Phoen/prometheus-exemplars

Support definition of exemplars on Prometheus datasources

datasource/prometheus/options.go

@@ -101,3 +101,10 @@ func ForwardCookies(cookies ...string) Option {
 		datasource.builder.JSONData.(map[string]interface{})["keepCookies"] = cookies
 	}
 }
+
+// Exemplars configures a list of exemplars on this datasource.
+func Exemplars(exemplars ...Exemplar) Option {
+	return func(datasource *Prometheus) {
+		datasource.builder.JSONData.(map[string]interface{})["exemplarTraceIdDestinations"] = exemplars
+	}
+}

datasource/prometheus/options_test.go

@@ -119,3 +119,16 @@ func TestForwardCookies(t *testing.T) {
 
 	req.ElementsMatch([]string{"foo", "bar"}, datasource.builder.JSONData.(map[string]interface{})["keepCookies"])
 }
+
+func TestExemplars(t *testing.T) {
+	req := require.New(t)
+
+	traceIDExemplar := Exemplar{
+		LabelName:     "traceID",
+		DatasourceUID: "tempo",
+	}
+
+	datasource := New("", "", Exemplars(traceIDExemplar))
+
+	req.ElementsMatch([]Exemplar{traceIDExemplar}, datasource.builder.JSONData.(map[string]interface{})["exemplarTraceIdDestinations"])
+}

datasource/prometheus/prometheus.go

@@ -10,6 +10,19 @@ import (
 
 var _ datasource.Datasource = Prometheus{}
 
+type Exemplar struct {
+	// The name of the field in the labels object that should be used to get the traceID.
+	LabelName string `json:"name"`
+
+	// The data source the exemplar is going to navigate to.
+	// Set this value for internal exemplar links.
+	DatasourceUID string `json:"datasourceUid"`
+
+	// The URL of the trace backend the user would go to see its trace.
+	// Set this value for external exemplar links.
+	URL string `json:"url,omitempty"`
+}
+
 type Prometheus struct {
 	builder *sdk.Datasource
 }