Configurable sliding window

CONFIG.md

@@ -586,6 +586,7 @@ metrics:
       match: '%{DATE} %{TIME} %{USER:user} %{NUMBER:val}'
       value: '{{.val}}'
       quantiles: {0.5: 0.05, 0.9: 0.01, 0.99: 0.001}
+      max_age: 10m
       labels:
           user: '{{.user}}'
 ```
@@ -594,8 +595,7 @@ The configuration is as follows:
 * `type` is `summary`.
 * `name`, `help`, `match`, `labels`, and `value` have the same meaning as for `gauge` metrics.
 * `quantiles` is a list of quantiles to be observed. `grok_exporter` does not provide exact values for the quantiles, but only estimations. For each quantile, you also specify an uncertainty that is tolerated for the estimation. In the example, we measure the median (0.5 quantile) with uncertainty 5%, the 90% quantile with uncertainty 1%, and the 99% quantile with uncertainty 0.1%. `quantiles` is optional, the default value is `{0.5: 0.05, 0.9: 0.01, 0.99: 0.001}`.
-
-Summaries represent a sliding time window of 10 minutes, i.e. if you observe a 0.5 quantile (median) of _x_, the value _x_ represents the median within the last 10 minutes. The time window is moved forward every 2 minutes.
+* `max_age` is a summary sliding window. By default, summaries represent a sliding time window of 10 minutes, i.e. if you observe a 0.5 quantile (median) of _x_, the value _x_ represents the median within the last 10 minutes. The time window is moved forward every 2 minutes.
 
 Output for the example log lines above::
 

config/v3/configV3.go

@@ -123,6 +123,7 @@ type MetricConfig struct {
 	Cumulative           bool                `yaml:",omitempty"`
 	Buckets              []float64           `yaml:",flow,omitempty"`
 	Quantiles            map[float64]float64 `yaml:",flow,omitempty"`
+	MaxAge               time.Duration       `yaml:"max_age,omitempty"`
 	Labels               map[string]string   `yaml:",omitempty"`
 	LabelTemplates       []template.Template `yaml:"-"` // parsed version of Labels, will not be serialized to yaml.
 	ValueTemplate        template.Template   `yaml:"-"` // parsed version of Value, will not be serialized to yaml.
@@ -147,6 +148,7 @@ type DefaultConfig struct {
 	Retention     time.Duration       `yaml:",omitempty"` // implicitly parsed with time.ParseDuration()
 	Buckets       []float64           `yaml:",flow,omitempty"`
 	Quantiles     map[float64]float64 `yaml:",flow,omitempty"`
+	MaxAge        time.Duration       `yaml:"max_age,omitempty"`
 	Labels        map[string]string   `yaml:",omitempty"`
 }
 
@@ -211,6 +213,9 @@ func applyImportDefaults(metricConfig *MetricConfig, defaults DefaultConfig) {
 	if metricConfig.Type == "summary" && len(metricConfig.Quantiles) == 0 {
 		metricConfig.Quantiles = defaults.Quantiles
 	}
+	if metricConfig.Type == "summary" && metricConfig.MaxAge == 0 {
+		metricConfig.MaxAge = defaults.MaxAge
+	}
 	if metricConfig.Type == "histogram" && len(metricConfig.Buckets) == 0 {
 		metricConfig.Buckets = defaults.Buckets
 	}
@@ -416,6 +421,7 @@ func (c ImportConfig) validate() error {
 			{"retention", c.Defaults.Retention != 0},
 			{"buckets", len(c.Defaults.Buckets) > 0},
 			{"quantiles", len(c.Defaults.Quantiles) > 0},
+			{"max_age", c.Defaults.MaxAge != 0},
 			{"labels", len(c.Defaults.Labels) > 0},
 		} {
 			if field.present {
@@ -496,16 +502,16 @@ func (c *MetricConfig) validate() error {
 	if err != nil {
 		return err
 	}
-	var cumulativeAllowed, bucketsAllowed, quantilesAllowed bool
+	var cumulativeAllowed, bucketsAllowed, quantilesAllowed, maxAgeAllowed bool
 	switch c.Type {
 	case "counter":
-		cumulativeAllowed, bucketsAllowed, quantilesAllowed = false, false, false
+		cumulativeAllowed, bucketsAllowed, quantilesAllowed, maxAgeAllowed = false, false, false, false
 	case "gauge":
-		cumulativeAllowed, bucketsAllowed, quantilesAllowed = true, false, false
+		cumulativeAllowed, bucketsAllowed, quantilesAllowed, maxAgeAllowed = true, false, false, false
 	case "histogram":
-		cumulativeAllowed, bucketsAllowed, quantilesAllowed = false, true, false
+		cumulativeAllowed, bucketsAllowed, quantilesAllowed, maxAgeAllowed = false, true, false, false
 	case "summary":
-		cumulativeAllowed, bucketsAllowed, quantilesAllowed = false, false, true
+		cumulativeAllowed, bucketsAllowed, quantilesAllowed, maxAgeAllowed = false, false, true, true
 	default:
 		return fmt.Errorf("Invalid 'metrics.type': '%v'. We currently only support 'counter' and 'gauge'.", c.Type)
 	}
@@ -517,7 +523,9 @@ func (c *MetricConfig) validate() error {
 	case !bucketsAllowed && len(c.Buckets) > 0:
 		return fmt.Errorf("Invalid metric configuration: 'metrics.buckets' cannot be used for %v metrics.", c.Type)
 	case !quantilesAllowed && len(c.Quantiles) > 0:
-		return fmt.Errorf("Invalid metric configuration: 'metrics.buckets' cannot be used for %v metrics.", c.Type)
+		return fmt.Errorf("Invalid metric configuration: 'metrics.quantiles' cannot be used for %v metrics.", c.Type)
+	case !maxAgeAllowed && c.MaxAge != 0:
+		return fmt.Errorf("Invalid metric configuration: 'metrics.max_age' cannot be used for %v metrics.", c.Type)
 	}
 	if len(c.DeleteMatch) > 0 && len(c.Labels) == 0 {
 		return fmt.Errorf("Invalid metric configuration: 'metrics.delete_match' is only supported for metrics with labels.")

exporter/metrics.go

@@ -471,6 +471,9 @@ func NewSummaryMetric(cfg *configuration.MetricConfig, regex *oniguruma.Regex, d
 	if len(cfg.Quantiles) > 0 {
 		summaryOpts.Objectives = cfg.Quantiles
 	}
+	if cfg.MaxAge != 0 {
+		summaryOpts.MaxAge = cfg.MaxAge
+	}
 	if len(cfg.Labels) == 0 {
 		return &summaryMetric{
 			observeMetric: newObserveMetric(cfg, regex, deleteRegex),