157 lines
3.2 KiB
Go
157 lines
3.2 KiB
Go
package starlark
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import (
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"fmt"
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"github.com/influxdata/telegraf"
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common "github.com/influxdata/telegraf/plugins/common/starlark"
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"github.com/influxdata/telegraf/plugins/processors"
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"go.starlark.net/starlark"
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)
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const (
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description = "Process metrics using a Starlark script"
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sampleConfig = `
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## The Starlark source can be set as a string in this configuration file, or
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## by referencing a file containing the script. Only one source or script
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## should be set at once.
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##
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## Source of the Starlark script.
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source = '''
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def apply(metric):
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return metric
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'''
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## File containing a Starlark script.
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# script = "/usr/local/bin/myscript.star"
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## The constants of the Starlark script.
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# [processors.starlark.constants]
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# max_size = 10
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# threshold = 0.75
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# default_name = "Julia"
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# debug_mode = true
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`
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)
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type Starlark struct {
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common.StarlarkCommon
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results []telegraf.Metric
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}
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func (s *Starlark) Init() error {
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err := s.StarlarkCommon.Init()
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if err != nil {
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return err
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}
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// The source should define an apply function.
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err = s.AddFunction("apply", &common.Metric{})
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if err != nil {
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return err
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}
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// Preallocate a slice for return values.
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s.results = make([]telegraf.Metric, 0, 10)
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return nil
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}
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func (s *Starlark) SampleConfig() string {
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return sampleConfig
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}
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func (s *Starlark) Description() string {
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return description
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}
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func (s *Starlark) Start(_ telegraf.Accumulator) error {
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return nil
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}
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func (s *Starlark) Add(metric telegraf.Metric, acc telegraf.Accumulator) error {
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parameters, found := s.GetParameters("apply")
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if !found {
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return fmt.Errorf("The parameters of the apply function could not be found")
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}
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parameters[0].(*common.Metric).Wrap(metric)
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rv, err := s.Call("apply")
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if err != nil {
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s.LogError(err)
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metric.Reject()
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return err
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}
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switch rv := rv.(type) {
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case *starlark.List:
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iter := rv.Iterate()
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defer iter.Done()
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var v starlark.Value
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for iter.Next(&v) {
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switch v := v.(type) {
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case *common.Metric:
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m := v.Unwrap()
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if containsMetric(s.results, m) {
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s.Log.Errorf("Duplicate metric reference detected")
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continue
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}
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s.results = append(s.results, m)
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acc.AddMetric(m)
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default:
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s.Log.Errorf("Invalid type returned in list: %s", v.Type())
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}
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}
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// If the script didn't return the original metrics, mark it as
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// successfully handled.
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if !containsMetric(s.results, metric) {
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metric.Accept()
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}
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// clear results
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for i := range s.results {
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s.results[i] = nil
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}
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s.results = s.results[:0]
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case *common.Metric:
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m := rv.Unwrap()
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// If the script returned a different metric, mark this metric as
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// successfully handled.
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if m != metric {
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metric.Accept()
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}
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acc.AddMetric(m)
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case starlark.NoneType:
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metric.Drop()
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default:
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return fmt.Errorf("Invalid type returned: %T", rv)
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}
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return nil
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}
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func (s *Starlark) Stop() error {
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return nil
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}
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func containsMetric(metrics []telegraf.Metric, metric telegraf.Metric) bool {
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for _, m := range metrics {
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if m == metric {
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return true
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}
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}
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return false
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}
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func init() {
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processors.AddStreaming("starlark", func() telegraf.StreamingProcessor {
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return &Starlark{
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StarlarkCommon: common.StarlarkCommon{
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StarlarkLoadFunc: common.LoadFunc,
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},
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}
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})
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}
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