Handle untyped/unknown metric types (#56)

* Update to Prometheus 2.5.0

Signed-off-by: Fabian Reinartz <freinartz@google.com>

* Update pkg/textparse to v2.5

Signed-off-by: Fabian Reinartz <freinartz@google.com>

* Handle Prometheus 2.5 unknown metric type

Signed-off-by: Fabian Reinartz <freinartz@google.com>

* Revert to 2.4.3 until upstream is fixed

Signed-off-by: Fabian Reinartz <freinartz@google.com>

Author: fabxc

README.md

@@ -49,9 +49,10 @@ can be used as a reference for setup:
 
 The matrix below lists the versions of Prometheus Server and other dependencies that have been qualified to work with releases of `stackdriver-prometheus-sidecar`.
 
-| sidecar version | prometheus version |
-| --- | --- |
-| 0.2.x | 2.4.3 |
+| sidecar version | **Prometheus 2.4.3** | **Prometheus 2.5.x** |
+|------------|------------------|-------------------|
+| **0.2.x**  |        ✓         |         -         |
+| **master** |        ✓         |         ✓         |
 
 ## Source Code Headers
 

cmd/stackdriver-prometheus-sidecar/main.go

@@ -613,8 +613,11 @@ func parseConfigFile(filename string) (map[string]string, []scrape.MetricMetadat
 	var staticMetadata []scrape.MetricMetadata
 	for _, sm := range fc.StaticMetadata {
 		switch sm.Type {
-		case textparse.MetricTypeCounter, textparse.MetricTypeGauge,
-			textparse.MetricTypeHistogram, textparse.MetricTypeSummary, textparse.MetricTypeUntyped:
+		case metadata.MetricTypeUntyped:
+			// Convert "untyped" to the "unknown" type used internally as of Prometheus 2.5.
+			sm.Type = textparse.MetricTypeUnknown
+		case textparse.MetricTypeCounter, textparse.MetricTypeGauge, textparse.MetricTypeHistogram,
+			textparse.MetricTypeSummary, textparse.MetricTypeUnknown:
 		default:
 			return nil, nil, errors.Errorf("invalid metric type %q", sm.Type)
 		}

metadata/cache.go

@@ -46,6 +46,10 @@ type Cache struct {
 // the target metadata endpoint.
 const DefaultEndpointPath = "/api/v1/targets/metadata"
 
+// The old metric type value for textparse.MetricTypeUnknown that is used in
+// Prometheus 2.4 and earlier.
+const MetricTypeUntyped = "untyped"
+
 // NewCache returns a new cache that gets populated by the metadata endpoint
 // at the given URL.
 // It uses the default endpoint path if no specific path is provided.
@@ -176,6 +180,10 @@ func (c *Cache) fetchMetric(ctx context.Context, job, instance, metric string) (
 	}
 	d := apiResp.Data[0]
 
+	// Convert legacy "untyped" type used before Prometheus 2.5.
+	if d.Type == MetricTypeUntyped {
+		d.Type = textparse.MetricTypeUnknown
+	}
 	return &metadataEntry{
 		MetricMetadata: scrape.MetricMetadata{
 			Metric: metric,
@@ -212,6 +220,10 @@ func (c *Cache) fetchBatch(ctx context.Context, job, instance string) (map[strin
 	result := make(map[string]*metadataEntry, len(apiResp.Data)+len(internalMetrics))
 
 	for _, md := range apiResp.Data {
+		// Convert legacy "untyped" type used before Prometheus 2.5.
+		if md.Type == MetricTypeUntyped {
+			md.Type = textparse.MetricTypeUnknown
+		}
 		result[md.Metric] = &metadataEntry{
 			MetricMetadata: scrape.MetricMetadata{
 				Metric: md.Metric,

metadata/cache_test.go

@@ -35,7 +35,8 @@ func TestCache_Get(t *testing.T) {
 		{Metric: "metric2", Type: textparse.MetricTypeGauge, Help: "help_metric2"},
 		{Metric: "metric3", Type: textparse.MetricTypeHistogram, Help: "help_metric3"},
 		{Metric: "metric4", Type: textparse.MetricTypeSummary, Help: "help_metric4"},
-		{Metric: "metric5", Type: textparse.MetricTypeUntyped, Help: "help_metric5"},
+		{Metric: "metric5", Type: textparse.MetricTypeUnknown, Help: "help_metric5"},
+		{Metric: "metric6", Type: MetricTypeUntyped, Help: "help_metric6"},
 	}
 	var handler func(qMetric, qMatch string) *apiResponse
 
@@ -129,6 +130,22 @@ func TestCache_Get(t *testing.T) {
 	}
 	expect(metrics[4], md)
 
+	// Test "untyped" metric type from Prometheus 2.4.
+	handler = func(qMetric, qMatch string) *apiResponse {
+		if qMetric != "metric6" {
+			t.Fatalf("unexpected metric %q in request", qMetric)
+		}
+		if qMatch != `{job="prometheus",instance="localhost:9090"}` {
+			t.Fatalf("unexpected matcher %q in request", qMatch)
+		}
+		return &apiResponse{Status: "success", Data: metrics[5:6]}
+	}
+	md, err = c.Get(ctx, "prometheus", "localhost:9090", "metric6")
+	if err != nil {
+		t.Fatal(err)
+	}
+	expect(apiMetadata{Metric: "metric6", Type: textparse.MetricTypeUnknown, Help: "help_metric6"}, md)
+
 	// The scrape layer's metrics should not fire off requests.
 	md, err = c.Get(ctx, "prometheus", "localhost:9090", "up")
 	if err != nil {

retrieval/series_cache.go

@@ -407,7 +407,7 @@ func (c *seriesCache) refresh(ctx context.Context, ref uint64) error {
 	case textparse.MetricTypeCounter:
 		ts.MetricKind = metric_pb.MetricDescriptor_CUMULATIVE
 		ts.ValueType = metric_pb.MetricDescriptor_DOUBLE
-	case textparse.MetricTypeGauge, textparse.MetricTypeUntyped:
+	case textparse.MetricTypeGauge, textparse.MetricTypeUnknown:
 		ts.MetricKind = metric_pb.MetricDescriptor_GAUGE
 		ts.ValueType = metric_pb.MetricDescriptor_DOUBLE
 	case textparse.MetricTypeSummary:

retrieval/transform.go

@@ -70,7 +70,7 @@ func (b *sampleBuilder) next(ctx context.Context, samples []tsdb.RefSample) (*mo
 		point.Interval.StartTime = getTimestamp(resetTimestamp)
 		point.Value = &monitoring_pb.TypedValue{&monitoring_pb.TypedValue_DoubleValue{v}}
 
-	case textparse.MetricTypeGauge, textparse.MetricTypeUntyped:
+	case textparse.MetricTypeGauge, textparse.MetricTypeUnknown:
 		point.Value = &monitoring_pb.TypedValue{&monitoring_pb.TypedValue_DoubleValue{sample.V}}
 
 	case textparse.MetricTypeSummary:

retrieval/transform_test.go

@@ -94,7 +94,7 @@ func TestSampleBuilder(t *testing.T) {
 			metadata: metadataMap{
 				"job1/instance1/metric1":      &scrape.MetricMetadata{Type: textparse.MetricTypeGauge, Metric: "metric1"},
 				"job1/instance1/metric2":      &scrape.MetricMetadata{Type: textparse.MetricTypeCounter, Metric: "metric2"},
-				"job1/instance1/labelnum_ok":  &scrape.MetricMetadata{Type: textparse.MetricTypeUntyped, Metric: "labelnum_ok"},
+				"job1/instance1/labelnum_ok":  &scrape.MetricMetadata{Type: textparse.MetricTypeUnknown, Metric: "labelnum_ok"},
 				"job1/instance1/labelnum_bad": &scrape.MetricMetadata{Type: textparse.MetricTypeGauge, Metric: "labelnum_bad"},
 			},
 			input: []tsdb.RefSample{