Merge pull request #76 from prometheus/histogram

Add support for histograms to parsers, extraction and creation.

Author: beorn7

extraction/metricfamilyprocessor.go

@@ -69,6 +69,10 @@ func extractMetricFamily(out Ingester, o *ProcessOptions, family *dto.MetricFami
 		if err := extractUntyped(out, o, family); err != nil {
 			return err
 		}
+	case dto.MetricType_HISTOGRAM:
+		if err := extractHistogram(out, o, family); err != nil {
+			return err
+		}
 	}
 	return nil
 }
@@ -227,3 +231,65 @@ func extractUntyped(out Ingester, o *ProcessOptions, f *dto.MetricFamily) error
 
 	return out.Ingest(samples)
 }
+
+func extractHistogram(out Ingester, o *ProcessOptions, f *dto.MetricFamily) error {
+	samples := make(model.Samples, 0, len(f.Metric))
+
+	for _, m := range f.Metric {
+		if m.Histogram == nil {
+			continue
+		}
+
+		timestamp := o.Timestamp
+		if m.TimestampMs != nil {
+			timestamp = model.TimestampFromUnixNano(*m.TimestampMs * 1000000)
+		}
+
+		for _, q := range m.Histogram.Bucket {
+			sample := new(model.Sample)
+			samples = append(samples, sample)
+
+			sample.Timestamp = timestamp
+			sample.Metric = model.Metric{}
+			metric := sample.Metric
+
+			for _, p := range m.Label {
+				metric[model.LabelName(p.GetName())] = model.LabelValue(p.GetValue())
+			}
+			metric[model.LabelName("le")] = model.LabelValue(fmt.Sprint(q.GetUpperBound()))
+
+			metric[model.MetricNameLabel] = model.LabelValue(f.GetName() + "_bucket")
+
+			sample.Value = model.SampleValue(q.GetCumulativeCount())
+		}
+		// TODO: If +Inf bucket is missing, add it.
+
+		if m.Histogram.SampleSum != nil {
+			sum := new(model.Sample)
+			sum.Timestamp = timestamp
+			metric := model.Metric{}
+			for _, p := range m.Label {
+				metric[model.LabelName(p.GetName())] = model.LabelValue(p.GetValue())
+			}
+			metric[model.MetricNameLabel] = model.LabelValue(f.GetName() + "_sum")
+			sum.Metric = metric
+			sum.Value = model.SampleValue(m.Histogram.GetSampleSum())
+			samples = append(samples, sum)
+		}
+
+		if m.Histogram.SampleCount != nil {
+			count := new(model.Sample)
+			count.Timestamp = timestamp
+			metric := model.Metric{}
+			for _, p := range m.Label {
+				metric[model.LabelName(p.GetName())] = model.LabelValue(p.GetValue())
+			}
+			metric[model.MetricNameLabel] = model.LabelValue(f.GetName() + "_count")
+			count.Metric = metric
+			count.Value = model.SampleValue(m.Histogram.GetSampleCount())
+			samples = append(samples, count)
+		}
+	}
+
+	return out.Ingest(samples)
+}

extraction/metricfamilyprocessor_test.go

@@ -103,6 +103,48 @@ func TestMetricFamilyProcessor(t *testing.T) {
 				},
 			},
 		},
+		{
+			in: "\x8d\x01\n\x1drequest_duration_microseconds\x12\x15The response latency.\x18\x04\"S:Q\b\x85\x15\x11\xcd\xcc\xccL\x8f\xcb:A\x1a\v\b{\x11\x00\x00\x00\x00\x00\x00Y@\x1a\f\b\x9c\x03\x11\x00\x00\x00\x00\x00\x00^@\x1a\f\b\xd0\x04\x11\x00\x00\x00\x00\x00\x00b@\x1a\f\b\xf4\v\x11\x9a\x99\x99\x99\x99\x99e@\x1a\f\b\x85\x15\x11\x00\x00\x00\x00\x00\x00\xf0\u007f",
+			expected: []model.Samples{
+				model.Samples{
+					&model.Sample{
+						Metric:    model.Metric{model.MetricNameLabel: "request_duration_microseconds_bucket", "le": "100"},
+						Value:     123,
+						Timestamp: testTime,
+					},
+					&model.Sample{
+						Metric:    model.Metric{model.MetricNameLabel: "request_duration_microseconds_bucket", "le": "120"},
+						Value:     412,
+						Timestamp: testTime,
+					},
+					&model.Sample{
+						Metric:    model.Metric{model.MetricNameLabel: "request_duration_microseconds_bucket", "le": "144"},
+						Value:     592,
+						Timestamp: testTime,
+					},
+					&model.Sample{
+						Metric:    model.Metric{model.MetricNameLabel: "request_duration_microseconds_bucket", "le": "172.8"},
+						Value:     1524,
+						Timestamp: testTime,
+					},
+					&model.Sample{
+						Metric:    model.Metric{model.MetricNameLabel: "request_duration_microseconds_bucket", "le": "+Inf"},
+						Value:     2693,
+						Timestamp: testTime,
+					},
+					&model.Sample{
+						Metric:    model.Metric{model.MetricNameLabel: "request_duration_microseconds_sum"},
+						Value:     1756047.3,
+						Timestamp: testTime,
+					},
+					&model.Sample{
+						Metric:    model.Metric{model.MetricNameLabel: "request_duration_microseconds_count"},
+						Value:     2693,
+						Timestamp: testTime,
+					},
+				},
+			},
+		},
 	}
 
 	for i, scenario := range scenarios {

text/create.go

@@ -139,6 +139,39 @@ func MetricFamilyToText(out io.Writer, in *dto.MetricFamily) (int, error) {
 				float64(metric.Summary.GetSampleCount()),
 				out,
 			)
+		case dto.MetricType_HISTOGRAM:
+			if metric.Histogram == nil {
+				return written, fmt.Errorf(
+					"expected summary in metric %s", metric,
+				)
+			}
+			for _, q := range metric.Histogram.Bucket {
+				n, err = writeSample(
+					name+"_bucket", metric,
+					"le", fmt.Sprint(q.GetUpperBound()),
+					float64(q.GetCumulativeCount()),
+					out,
+				)
+				written += n
+				if err != nil {
+					return written, err
+				}
+                        // TODO: Add +inf bucket if it's missing.
+			}
+			n, err = writeSample(
+				name+"_sum", metric, "", "",
+				metric.Histogram.GetSampleSum(),
+				out,
+			)
+			if err != nil {
+				return written, err
+			}
+			written += n
+			n, err = writeSample(
+				name+"_count", metric, "", "",
+				float64(metric.Histogram.GetSampleCount()),
+				out,
+			)
 		default:
 			return written, fmt.Errorf(
 				"unexpected type in metric %s", metric,

text/create_test.go

@@ -219,6 +219,54 @@ summary_name{name_1="value 1",name_2="value 2",quantile="0.9"} 2
 summary_name{name_1="value 1",name_2="value 2",quantile="0.99"} 3
 summary_name_sum{name_1="value 1",name_2="value 2"} 2010.1971
 summary_name_count{name_1="value 1",name_2="value 2"} 4711
+`,
+		},
+		// 4: Histogram
+		{
+			in: &dto.MetricFamily{
+				Name: proto.String("request_duration_microseconds"),
+				Help: proto.String("The response latency."),
+				Type: dto.MetricType_HISTOGRAM.Enum(),
+				Metric: []*dto.Metric{
+					&dto.Metric{
+						Histogram: &dto.Histogram{
+							SampleCount: proto.Uint64(2693),
+							SampleSum:   proto.Float64(1756047.3),
+							Bucket: []*dto.Bucket{
+								&dto.Bucket{
+									UpperBound:      proto.Float64(100),
+									CumulativeCount: proto.Uint64(123),
+								},
+								&dto.Bucket{
+									UpperBound:      proto.Float64(120),
+									CumulativeCount: proto.Uint64(412),
+								},
+								&dto.Bucket{
+									UpperBound:      proto.Float64(144),
+									CumulativeCount: proto.Uint64(592),
+								},
+								&dto.Bucket{
+									UpperBound:      proto.Float64(172.8),
+									CumulativeCount: proto.Uint64(1524),
+								},
+								&dto.Bucket{
+									UpperBound:      proto.Float64(math.Inf(+1)),
+									CumulativeCount: proto.Uint64(2693),
+								},
+							},
+						},
+					},
+				},
+			},
+			out: `# HELP request_duration_microseconds The response latency.
+# TYPE request_duration_microseconds histogram
+request_duration_microseconds_bucket{le="100"} 123
+request_duration_microseconds_bucket{le="120"} 412
+request_duration_microseconds_bucket{le="144"} 592
+request_duration_microseconds_bucket{le="172.8"} 1524
+request_duration_microseconds_bucket{le="+Inf"} 2693
+request_duration_microseconds_sum 1.7560473e+06
+request_duration_microseconds_count 2693
 `,
 		},
 	}