telegraf/plugins/processors/defaults/defaults.go

73 lines
2.3 KiB
Go

package defaults
import (
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/plugins/processors"
"strings"
)
const sampleConfig = `
## Ensures a set of fields always exists on your metric(s) with their
## respective default value.
## For any given field pair (key = default), if it's not set, a field
## is set on the metric with the specified default.
##
## A field is considered not set if it is nil on the incoming metric;
## or it is not nil but its value is an empty string or is a string
## of one or more spaces.
## <target-field> = <value>
# [processors.defaults.fields]
# field_1 = "bar"
# time_idle = 0
# is_error = true
`
// Defaults is a processor for ensuring certain fields always exist
// on your Metrics with at least a default value.
type Defaults struct {
DefaultFieldsSets map[string]interface{} `toml:"fields"`
}
// SampleConfig represents a sample toml config for this plugin.
func (def *Defaults) SampleConfig() string {
return sampleConfig
}
// Description is a brief description of this processor plugin's behaviour.
func (def *Defaults) Description() string {
return "Defaults sets default value(s) for specified fields that are not set on incoming metrics."
}
// Apply contains the main implementation of this processor.
// For each metric in 'inputMetrics', it goes over each default pair.
// If the field in the pair does not exist on the metric, the associated default is added.
// If the field was found, then, if its value is the empty string or one or more spaces, it is replaced
// by the associated default.
func (def *Defaults) Apply(inputMetrics ...telegraf.Metric) []telegraf.Metric {
for _, metric := range inputMetrics {
for defField, defValue := range def.DefaultFieldsSets {
if maybeCurrent, isSet := metric.GetField(defField); !isSet {
metric.AddField(defField, defValue)
} else if trimmed, isStr := maybeTrimmedString(maybeCurrent); isStr && trimmed == "" {
metric.RemoveField(defField)
metric.AddField(defField, defValue)
}
}
}
return inputMetrics
}
func maybeTrimmedString(v interface{}) (string, bool) {
switch value := v.(type) {
case string:
return strings.TrimSpace(value), true
}
return "", false
}
func init() {
processors.Add("defaults", func() telegraf.Processor {
return &Defaults{}
})
}