Merge pull request #861 from yeya24/add-exemplars

Add exemplars API support

Author: beorn7

api/prometheus/v1/api.go

@@ -123,6 +123,7 @@ const (
 epAlertManagers = apiPrefix + "/alertmanagers"
 epQuery = apiPrefix + "/query"
 epQueryRange = apiPrefix + "/query_range"
+epQueryExemplars = apiPrefix + "/query_exemplars"
 epLabels = apiPrefix + "/labels"
 epLabelValues = apiPrefix + "/label/:name/values"
 epSeries = apiPrefix + "/series"
@@ -239,6 +240,8 @@ type API interface {
 Query(ctx context.Context, query string, ts time.Time) (model.Value, Warnings, error)
 // QueryRange performs a query for the given range.
 QueryRange(ctx context.Context, query string, r Range) (model.Value, Warnings, error)
+// QueryExemplars performs a query for exemplars by the given query and time range.
+QueryExemplars(ctx context.Context, query string, startTime time.Time, endTime time.Time) ([]ExemplarQueryResult, error)
 // Buildinfo returns various build information properties about the Prometheus server
 Buildinfo(ctx context.Context) (BuildinfoResult, error)
 // Runtimeinfo returns the various runtime information properties about the Prometheus server.
@@ -588,6 +591,18 @@ func (qr *queryResult) UnmarshalJSON(b []byte) error {
 return err
 }
 
+// Exemplar is additional information associated with a time series.
+type Exemplar struct {
+Labels model.LabelSet `json:"labels"`
+Value model.SampleValue `json:"value"`
+Timestamp model.Time `json:"timestamp"`
+}
+
+type ExemplarQueryResult struct {
+SeriesLabels model.LabelSet `json:"seriesLabels"`
+Exemplars []Exemplar `json:"exemplars"`
+}
+
 // NewAPI returns a new API for the client.
 //
 // It is safe to use the returned API from multiple goroutines.
@@ -967,7 +982,29 @@ func (h *httpAPI) TSDB(ctx context.Context) (TSDBResult, error) {
 
 var res TSDBResult
 return res, json.Unmarshal(body, &res)
+}
+
+func (h *httpAPI) QueryExemplars(ctx context.Context, query string, startTime time.Time, endTime time.Time) ([]ExemplarQueryResult, error) {
+u := h.client.URL(epQueryExemplars, nil)
+q := u.Query()
+
+q.Set("query", query)
+q.Set("start", formatTime(startTime))
+q.Set("end", formatTime(endTime))
+u.RawQuery = q.Encode()
 
+req, err := http.NewRequest(http.MethodGet, u.String(), nil)
+if err != nil {
+return nil, err
+}
+
+_, body, _, err := h.client.Do(ctx, req)
+if err != nil {
+return nil, err
+}
+
+var res []ExemplarQueryResult
+return res, json.Unmarshal(body, &res)
 }
 
 // Warnings is an array of non critical errors

api/prometheus/v1/api_test.go

@@ -230,6 +230,13 @@ func TestAPIs(t *testing.T) {
 }
 }
 
+doQueryExemplars := func(query string, startTime time.Time, endTime time.Time) func() (interface{}, Warnings, error) {
+return func() (interface{}, Warnings, error) {
+v, err := promAPI.QueryExemplars(context.Background(), query, startTime, endTime)
+return v, nil, err
+}
+}
+
 queryTests := []apiTest{
 {
 do: doQuery("2", testTime),
@@ -1190,6 +1197,66 @@ func TestAPIs(t *testing.T) {
 },
 },
 },
+
+{
+do: doQueryExemplars("tns_request_duration_seconds_bucket", testTime.Add(-1*time.Minute), testTime),
+reqMethod: "GET",
+reqPath: "/api/v1/query_exemplars",
+inErr: fmt.Errorf("some error"),
+err: fmt.Errorf("some error"),
+},
+
+{
+do: doQueryExemplars("tns_request_duration_seconds_bucket", testTime.Add(-1*time.Minute), testTime),
+reqMethod: "GET",
+reqPath: "/api/v1/query_exemplars",
+inRes: []interface{}{
+map[string]interface{}{
+"seriesLabels": map[string]interface{}{
+"__name__": "tns_request_duration_seconds_bucket",
+"instance": "app:80",
+"job": "tns/app",
+},
+"exemplars": []interface{}{
+map[string]interface{}{
+"labels": map[string]interface{}{
+"traceID": "19fd8c8a33975a23",
+},
+"value": "0.003863295",
+"timestamp": model.TimeFromUnixNano(testTime.UnixNano()),
+},
+map[string]interface{}{
+"labels": map[string]interface{}{
+"traceID": "67f743f07cc786b0",
+},
+"value": "0.001535405",
+"timestamp": model.TimeFromUnixNano(testTime.UnixNano()),
+},
+},
+},
+},
+res: []ExemplarQueryResult{
+{
+SeriesLabels: model.LabelSet{
+"__name__": "tns_request_duration_seconds_bucket",
+"instance": "app:80",
+"job": "tns/app",
+},
+Exemplars: []Exemplar{
+{
+Labels: model.LabelSet{"traceID": "19fd8c8a33975a23"},
+Value: 0.003863295,
+Timestamp: model.TimeFromUnixNano(testTime.UnixNano()),
+},
+{
+Labels: model.LabelSet{"traceID": "67f743f07cc786b0"},
+Value: 0.001535405,
+Timestamp: model.TimeFromUnixNano(testTime.UnixNano()),
+},
+},
+},
+},
+},
 }
 
 var tests []apiTest