Grab Timestamps from Metric

README.md

@@ -83,6 +83,10 @@ $ docker run --rm -it -p 9090:9090 -v $PWD/examples/prometheus.yml:/etc/promethe
 ```
 Then head over to http://localhost:9090/graph?g0.range_input=1h&g0.expr=example_value_active&g0.tab=1 or http://localhost:9090/targets to check the scraped metrics or the targets.
 
+## Using custom timestamps
+
+This exporter allows you to use a field of the metric as the (unix/epoch) timestamp for the data as an int64. However, this may lead to unexpected behaviour, as the prometheus implements a [Staleness](https://prometheus.io/docs/prometheus/latest/querying/basics/#staleness) mechanism. Including timestamps in metrics disabled this staleness handling and can make data visible for longer than expected.
+
 ## Exposing metrics through HTTPS
 
 TLS configuration supported by this exporter can be found at [exporter-toolkit/web](https://github.com/prometheus/exporter-toolkit/blob/v0.5.1/docs/web-configuration.md)

config/config.go

@@ -22,13 +22,14 @@ import (
 
 // Metric contains values that define a metric
 type Metric struct {
-	Name      string
-	Path      string
-	Labels    map[string]string
-	Type      ScrapeType
-	ValueType ValueType
-	Help      string
-	Values    map[string]string
+	Name           string
+	Path           string
+	Labels         map[string]string
+	Type           ScrapeType
+	ValueType      ValueType
+	EpochTimestamp string
+	Help           string
+	Values         map[string]string
 }
 
 type ScrapeType string

examples/config.yml

@@ -8,7 +8,12 @@ modules:
       labels:
         environment: beta # static label
         location: "planet-{.location}"          # dynamic label
-
+    - name: example_timestamped_value
+      path: "{ .values[?(@.state == "INACTIVE")] }"
+      epochTimestamp: "{ .timestamp }"
+      help: Example of a timestamped value scrape in the json
+      labels:
+        environment: beta # static label
     - name: example_value
       type: object
       help: Example of sub-level value scrapes from a json

examples/data.json

@@ -1,5 +1,6 @@
 {
     "counter": 1234,
+    "timestamp": 1657568506,
     "values": [
         {
             "id": "id-A",

exporter/collector.go

@@ -16,6 +16,7 @@ package exporter
 import (
 	"bytes"
 	"encoding/json"
+	"time"
 
 	"github.com/go-kit/log"
 	"github.com/go-kit/log/level"
@@ -31,12 +32,13 @@ type JSONMetricCollector struct {
 }
 
 type JSONMetric struct {
-	Desc            *prometheus.Desc
-	Type            config.ScrapeType
-	KeyJSONPath     string
-	ValueJSONPath   string
-	LabelsJSONPaths []string
-	ValueType       prometheus.ValueType
+	Desc                   *prometheus.Desc
+	Type                   config.ScrapeType
+	KeyJSONPath            string
+	ValueJSONPath          string
+	LabelsJSONPaths        []string
+	ValueType              prometheus.ValueType
+	EpochTimestampJSONPath string
 }
 
 func (mc JSONMetricCollector) Describe(ch chan<- *prometheus.Desc) {
@@ -56,13 +58,13 @@ func (mc JSONMetricCollector) Collect(ch chan<- prometheus.Metric) {
 			}
 
 			if floatValue, err := SanitizeValue(value); err == nil {
-
-				ch <- prometheus.MustNewConstMetric(
+				metric := prometheus.MustNewConstMetric(
 					m.Desc,
 					m.ValueType,
 					floatValue,
 					extractLabels(mc.Logger, mc.Data, m.LabelsJSONPaths)...,
 				)
+				ch <- timestampMetric(mc.Logger, m, mc.Data, metric)
 			} else {
 				level.Error(mc.Logger).Log("msg", "Failed to convert extracted value to float64", "path", m.KeyJSONPath, "value", value, "err", err, "metric", m.Desc)
 				continue
@@ -90,12 +92,13 @@ func (mc JSONMetricCollector) Collect(ch chan<- prometheus.Metric) {
 					}
 
 					if floatValue, err := SanitizeValue(value); err == nil {
-						ch <- prometheus.MustNewConstMetric(
+						metric := prometheus.MustNewConstMetric(
 							m.Desc,
 							m.ValueType,
 							floatValue,
 							extractLabels(mc.Logger, jdata, m.LabelsJSONPaths)...,
 						)
+						ch <- timestampMetric(mc.Logger, m, jdata, metric)
 					} else {
 						level.Error(mc.Logger).Log("msg", "Failed to convert extracted value to float64", "path", m.ValueJSONPath, "value", value, "err", err, "metric", m.Desc)
 						continue
@@ -157,3 +160,21 @@ func extractLabels(logger log.Logger, data []byte, paths []string) []string {
 	}
 	return labels
 }
+
+func timestampMetric(logger log.Logger, m JSONMetric, data []byte, pm prometheus.Metric) prometheus.Metric {
+	if m.EpochTimestampJSONPath == "" {
+		return pm
+	}
+	ts, err := extractValue(logger, data, m.EpochTimestampJSONPath, false)
+	if err != nil {
+		level.Error(logger).Log("msg", "Failed to extract timestamp for metric", "path", m.KeyJSONPath, "err", err, "metric", m.Desc)
+		return pm
+	}
+	epochTime, err := SanitizeIntValue(ts)
+	if err != nil {
+		level.Error(logger).Log("msg", "Failed to parse timestamp for metric", "path", m.KeyJSONPath, "err", err, "metric", m.Desc)
+		return pm
+	}
+	timestamp := time.UnixMilli(epochTime)
+	return prometheus.NewMetricWithTimestamp(timestamp, pm)
+}

exporter/util.go

@@ -62,6 +62,19 @@ func SanitizeValue(s string) (float64, error) {
 	return value, fmt.Errorf(resultErr)
 }
 
+func SanitizeIntValue(s string) (int64, error) {
+	var err error
+	var value int64
+	var resultErr string
+
+	if value, err = strconv.ParseInt(s, 10, 64); err == nil {
+		return value, nil
+	}
+	resultErr = fmt.Sprintf("%s", err)
+
+	return value, fmt.Errorf(resultErr)
+}
+
 func CreateMetricsList(c config.Module) ([]JSONMetric, error) {
 	var (
 		metrics   []JSONMetric
@@ -91,9 +104,10 @@ func CreateMetricsList(c config.Module) ([]JSONMetric, error) {
 					variableLabels,
 					nil,
 				),
-				KeyJSONPath:     metric.Path,
-				LabelsJSONPaths: variableLabelsValues,
-				ValueType:       valueType,
+				KeyJSONPath:            metric.Path,
+				LabelsJSONPaths:        variableLabelsValues,
+				ValueType:              valueType,
+				EpochTimestampJSONPath: metric.EpochTimestamp,
 			}
 			metrics = append(metrics, jsonMetric)
 		case config.ObjectScrape:
@@ -112,10 +126,11 @@ func CreateMetricsList(c config.Module) ([]JSONMetric, error) {
 						variableLabels,
 						nil,
 					),
-					KeyJSONPath:     metric.Path,
-					ValueJSONPath:   valuePath,
-					LabelsJSONPaths: variableLabelsValues,
-					ValueType:       valueType,
+					KeyJSONPath:            metric.Path,
+					ValueJSONPath:          valuePath,
+					LabelsJSONPaths:        variableLabelsValues,
+					ValueType:              valueType,
+					EpochTimestampJSONPath: metric.EpochTimestamp,
 				}
 				metrics = append(metrics, jsonMetric)
 			}