Allow overriding the collection_jitter and precision per input

agent/agent.go

@@ -246,12 +246,20 @@ func (a *Agent) startInputs(
 
 	for _, input := range inputs {
 		if si, ok := input.Input.(telegraf.ServiceInput); ok {
-			// Service input plugins are not subject to timestamp rounding.
+			// Service input plugins are not normally subject to timestamp
+			// rounding except for when precision is set on the input plugin.
+			//
 			// This only applies to the accumulator passed to Start(), the
 			// Gather() accumulator does apply rounding according to the
-			// precision agent setting.
+			// precision and interval agent/plugin settings.
+			var interval time.Duration
+			var precision time.Duration
+			if input.Config.Precision != 0 {
+				precision = input.Config.Precision
+			}
+
 			acc := NewAccumulator(input, dst)
-			acc.SetPrecision(time.Nanosecond)
+			acc.SetPrecision(getPrecision(precision, interval))
 
 			err := si.Start(acc)
 			if err != nil {
@@ -276,14 +284,24 @@ func (a *Agent) runInputs(
 ) error {
 	var wg sync.WaitGroup
 	for _, input := range unit.inputs {
-		interval := a.Config.Agent.Interval.Duration
-		jitter := a.Config.Agent.CollectionJitter.Duration
-
 		// Overwrite agent interval if this plugin has its own.
+		interval := a.Config.Agent.Interval.Duration
 		if input.Config.Interval != 0 {
 			interval = input.Config.Interval
 		}
 
+		// Overwrite agent precision if this plugin has its own.
+		precision := a.Config.Agent.Precision.Duration
+		if input.Config.Precision != 0 {
+			precision = input.Config.Precision
+		}
+
+		// Overwrite agent collection_jitter if this plugin has its own.
+		jitter := a.Config.Agent.CollectionJitter.Duration
+		if input.Config.CollectionJitter != 0 {
+			jitter = input.Config.CollectionJitter
+		}
+
 		var ticker Ticker
 		if a.Config.Agent.RoundInterval {
 			ticker = NewAlignedTicker(startTime, interval, jitter)
@@ -293,7 +311,7 @@ func (a *Agent) runInputs(
 		defer ticker.Stop()
 
 		acc := NewAccumulator(input, unit.dst)
-		acc.SetPrecision(a.Precision())
+		acc.SetPrecision(getPrecision(precision, interval))
 
 		wg.Add(1)
 		go func(input *models.RunningInput) {
@@ -368,12 +386,24 @@ func (a *Agent) testRunInputs(
 		go func(input *models.RunningInput) {
 			defer wg.Done()
 
+			// Overwrite agent interval if this plugin has its own.
+			interval := a.Config.Agent.Interval.Duration
+			if input.Config.Interval != 0 {
+				interval = input.Config.Interval
+			}
+
+			// Overwrite agent precision if this plugin has its own.
+			precision := a.Config.Agent.Precision.Duration
+			if input.Config.Precision != 0 {
+				precision = input.Config.Precision
+			}
+
 			// Run plugins that require multiple gathers to calculate rate
 			// and delta metrics twice.
 			switch input.Config.Name {
 			case "cpu", "mongodb", "procstat":
 				nulAcc := NewAccumulator(input, nul)
-				nulAcc.SetPrecision(a.Precision())
+				nulAcc.SetPrecision(getPrecision(precision, interval))
 				if err := input.Input.Gather(nulAcc); err != nil {
 					nulAcc.AddError(err)
 				}
@@ -382,7 +412,7 @@ func (a *Agent) testRunInputs(
 			}
 
 			acc := NewAccumulator(input, unit.dst)
-			acc.SetPrecision(a.Precision())
+			acc.SetPrecision(getPrecision(precision, interval))
 
 			if err := input.Input.Gather(acc); err != nil {
 				acc.AddError(err)
@@ -580,8 +610,11 @@ func (a *Agent) runAggregators(
 		go func(agg *models.RunningAggregator) {
 			defer wg.Done()
 
+			interval := a.Config.Agent.Interval.Duration
+			precision := a.Config.Agent.Precision.Duration
+
 			acc := NewAccumulator(agg, unit.aggC)
-			acc.SetPrecision(a.Precision())
+			acc.SetPrecision(getPrecision(precision, interval))
 			a.push(ctx, agg, acc)
 		}(agg)
 	}
@@ -705,8 +738,8 @@ func (a *Agent) runOutputs(
 
 		jitter := jitter
 		// Overwrite agent flush_jitter if this plugin has its own.
-		if output.Config.FlushJitter != nil {
-			jitter = *output.Config.FlushJitter
+		if output.Config.FlushJitter != 0 {
+			jitter = output.Config.FlushJitter
 		}
 
 		wg.Add(1)
@@ -1063,10 +1096,7 @@ func (a *Agent) once(ctx context.Context, wait time.Duration) error {
 }
 
 // Returns the rounding precision for metrics.
-func (a *Agent) Precision() time.Duration {
-	precision := a.Config.Agent.Precision.Duration
-	interval := a.Config.Agent.Interval.Duration
-
+func getPrecision(precision, interval time.Duration) time.Duration {
 	if precision > 0 {
 		return precision
 	}

config/config.go

@@ -1075,44 +1075,18 @@ func buildAggregator(name string, tbl *ast.Table) (*models.AggregatorConfig, err
 		Grace:  time.Second * 0,
 	}
 
-	if node, ok := tbl.Fields["period"]; ok {
-		if kv, ok := node.(*ast.KeyValue); ok {
-			if str, ok := kv.Value.(*ast.String); ok {
-				dur, err := time.ParseDuration(str.Value)
-				if err != nil {
-					return nil, err
-				}
-
-				conf.Period = dur
-			}
-		}
+	if err := getConfigDuration(tbl, "period", &conf.Period); err != nil {
+		return nil, err
 	}
 
-	if node, ok := tbl.Fields["delay"]; ok {
-		if kv, ok := node.(*ast.KeyValue); ok {
-			if str, ok := kv.Value.(*ast.String); ok {
-				dur, err := time.ParseDuration(str.Value)
-				if err != nil {
-					return nil, err
-				}
-
-				conf.Delay = dur
-			}
-		}
+	if err := getConfigDuration(tbl, "delay", &conf.Delay); err != nil {
+		return nil, err
 	}
 
-	if node, ok := tbl.Fields["grace"]; ok {
-		if kv, ok := node.(*ast.KeyValue); ok {
-			if str, ok := kv.Value.(*ast.String); ok {
-				dur, err := time.ParseDuration(str.Value)
-				if err != nil {
-					return nil, err
-				}
-
-				conf.Grace = dur
-			}
-		}
+	if err := getConfigDuration(tbl, "grace", &conf.Grace); err != nil {
+		return nil, err
 	}
+
 	if node, ok := tbl.Fields["drop_original"]; ok {
 		if kv, ok := node.(*ast.KeyValue); ok {
 			if b, ok := kv.Value.(*ast.Boolean); ok {
@@ -1166,9 +1140,6 @@ func buildAggregator(name string, tbl *ast.Table) (*models.AggregatorConfig, err
 		}
 	}
 
-	delete(tbl.Fields, "period")
-	delete(tbl.Fields, "delay")
-	delete(tbl.Fields, "grace")
 	delete(tbl.Fields, "drop_original")
 	delete(tbl.Fields, "name_prefix")
 	delete(tbl.Fields, "name_suffix")
@@ -1361,17 +1332,17 @@ func buildFilter(tbl *ast.Table) (models.Filter, error) {
 // models.InputConfig to be inserted into models.RunningInput
 func buildInput(name string, tbl *ast.Table) (*models.InputConfig, error) {
 	cp := &models.InputConfig{Name: name}
-	if node, ok := tbl.Fields["interval"]; ok {
-		if kv, ok := node.(*ast.KeyValue); ok {
-			if str, ok := kv.Value.(*ast.String); ok {
-				dur, err := time.ParseDuration(str.Value)
-				if err != nil {
-					return nil, err
-				}
 
-				cp.Interval = dur
-			}
-		}
+	if err := getConfigDuration(tbl, "interval", &cp.Interval); err != nil {
+		return nil, err
+	}
+
+	if err := getConfigDuration(tbl, "precision", &cp.Precision); err != nil {
+		return nil, err
+	}
+
+	if err := getConfigDuration(tbl, "collection_jitter", &cp.CollectionJitter); err != nil {
+		return nil, err
 	}
 
 	if node, ok := tbl.Fields["name_prefix"]; ok {
@@ -1419,7 +1390,6 @@ func buildInput(name string, tbl *ast.Table) (*models.InputConfig, error) {
 	delete(tbl.Fields, "name_suffix")
 	delete(tbl.Fields, "name_override")
 	delete(tbl.Fields, "alias")
-	delete(tbl.Fields, "interval")
 	delete(tbl.Fields, "tags")
 	var err error
 	cp.Filter, err = buildFilter(tbl)
@@ -2141,30 +2111,12 @@ func buildOutput(name string, tbl *ast.Table) (*models.OutputConfig, error) {
 		oc.Filter.NamePass = oc.Filter.FieldPass
 	}
 
-	if node, ok := tbl.Fields["flush_interval"]; ok {
-		if kv, ok := node.(*ast.KeyValue); ok {
-			if str, ok := kv.Value.(*ast.String); ok {
-				dur, err := time.ParseDuration(str.Value)
-				if err != nil {
-					return nil, err
-				}
-
-				oc.FlushInterval = dur
-			}
-		}
+	if err := getConfigDuration(tbl, "flush_interval", &oc.FlushInterval); err != nil {
+		return nil, err
 	}
 
-	if node, ok := tbl.Fields["flush_jitter"]; ok {
-		if kv, ok := node.(*ast.KeyValue); ok {
-			if str, ok := kv.Value.(*ast.String); ok {
-				dur, err := time.ParseDuration(str.Value)
-				if err != nil {
-					return nil, err
-				}
-				oc.FlushJitter = new(time.Duration)
-				*oc.FlushJitter = dur
-			}
-		}
+	if err := getConfigDuration(tbl, "flush_jitter", &oc.FlushJitter); err != nil {
+		return nil, err
 	}
 
 	if node, ok := tbl.Fields["metric_buffer_limit"]; ok {
@@ -2223,8 +2175,6 @@ func buildOutput(name string, tbl *ast.Table) (*models.OutputConfig, error) {
 		}
 	}
 
-	delete(tbl.Fields, "flush_interval")
-	delete(tbl.Fields, "flush_jitter")
 	delete(tbl.Fields, "metric_buffer_limit")
 	delete(tbl.Fields, "metric_batch_size")
 	delete(tbl.Fields, "alias")
@@ -2241,3 +2191,19 @@ func buildOutput(name string, tbl *ast.Table) (*models.OutputConfig, error) {
 type unwrappable interface {
 	Unwrap() telegraf.Processor
 }
+
+func getConfigDuration(tbl *ast.Table, key string, target *time.Duration) error {
+	if node, ok := tbl.Fields[key]; ok {
+		if kv, ok := node.(*ast.KeyValue); ok {
+			if str, ok := kv.Value.(*ast.String); ok {
+				d, err := time.ParseDuration(str.Value)
+				if err != nil {
+					return err
+				}
+				delete(tbl.Fields, key)
+				*target = d
+			}
+		}
+	}
+	return nil
+}

docs/CONFIGURATION.md

@@ -132,7 +132,6 @@ The agent table configures Telegraf and the defaults used across all plugins.
   running a large number of telegraf instances. ie, a jitter of 5s and interval
   10s means flushes will happen every 10-15s.
 
-
 - **precision**:
   Collected metrics are rounded to the precision specified as an [interval][].
 
@@ -194,13 +193,32 @@ driven operation.
 Parameters that can be used with any input plugin:
 
 - **alias**: Name an instance of a plugin.
-- **interval**: How often to gather this metric. Normal plugins use a single
-  global interval, but if one particular input should be run less or more
-  often, you can configure that here.
+
+- **interval**:
+  Overrides the `interval` setting of the [agent][Agent] for the plugin.  How
+  often to gather this metric. Normal plugins use a single global interval, but
+  if one particular input should be run less or more often, you can configure
+  that here.
+
+- **precision**:
+  Overrides the `precision` setting of the [agent][Agent] for the plugin.
+  Collected metrics are rounded to the precision specified as an [interval][].
+
+  When this value is set on a service input, multiple events occuring at the
+  same timestamp may be merged by the output database.
+
+- **collection_jitter**:
+  Overrides the `collection_jitter` setting of the [agent][Agent] for the
+  plugin.  Collection jitter is used to jitter the collection by a random
+  [interval][].
+
 - **name_override**: Override the base name of the measurement.  (Default is
   the name of the input).
+
 - **name_prefix**: Specifies a prefix to attach to the measurement name.
+
 - **name_suffix**: Specifies a suffix to attach to the measurement name.
+
 - **tags**: A map of tags to apply to a specific input's measurements.
 
 The [metric filtering][] parameters can be used to limit what metrics are

models/running_input.go

@@ -56,9 +56,11 @@ func NewRunningInput(input telegraf.Input, config *InputConfig) *RunningInput {
 
 // InputConfig is the common config for all inputs.
 type InputConfig struct {
-	Name     string
-	Alias    string
-	Interval time.Duration
+	Name             string
+	Alias            string
+	Interval         time.Duration
+	CollectionJitter time.Duration
+	Precision        time.Duration
 
 	NameOverride      string
 	MeasurementPrefix string

models/running_output.go

@@ -24,7 +24,7 @@ type OutputConfig struct {
 	Filter Filter
 
 	FlushInterval     time.Duration
-	FlushJitter       *time.Duration
+	FlushJitter       time.Duration
 	MetricBufferLimit int
 	MetricBatchSize   int