87 lines
1.9 KiB
Go
87 lines
1.9 KiB
Go
package taglimit
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import (
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"fmt"
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"github.com/influxdata/telegraf"
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"github.com/influxdata/telegraf/plugins/processors"
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"log"
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)
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const sampleConfig = `
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## Maximum number of tags to preserve
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limit = 10
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## List of tags to preferentially preserve
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keep = ["foo", "bar", "baz"]
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`
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type TagLimit struct {
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Limit int `toml:"limit"`
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Keep []string `toml:"keep"`
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init bool
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keepTags map[string]string
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}
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func (d *TagLimit) SampleConfig() string {
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return sampleConfig
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}
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func (d *TagLimit) Description() string {
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return "Restricts the number of tags that can pass through this filter and chooses which tags to preserve when over the limit."
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}
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func (d *TagLimit) initOnce() error {
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if d.init {
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return nil
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}
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if len(d.Keep) > d.Limit {
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return fmt.Errorf("%d keep tags is greater than %d total tag limit", len(d.Keep), d.Limit)
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}
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d.keepTags = make(map[string]string)
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// convert list of tags-to-keep to a map so we can do constant-time lookups
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for _, tag_key := range d.Keep {
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d.keepTags[tag_key] = ""
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}
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d.init = true
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return nil
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}
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func (d *TagLimit) Apply(in ...telegraf.Metric) []telegraf.Metric {
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err := d.initOnce()
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if err != nil {
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log.Printf("E! [processors.tag_limit] could not create tag_limit processor: %v", err)
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return in
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}
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for _, point := range in {
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pointOriginalTags := point.TagList()
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lenPointTags := len(pointOriginalTags)
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if lenPointTags <= d.Limit {
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continue
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}
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tagsToRemove := make([]string, lenPointTags-d.Limit)
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removeIdx := 0
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// remove extraneous tags, stop once we're at the limit
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for _, t := range pointOriginalTags {
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if _, ok := d.keepTags[t.Key]; !ok {
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tagsToRemove[removeIdx] = t.Key
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removeIdx++
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lenPointTags--
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}
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if lenPointTags <= d.Limit {
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break
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}
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}
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for _, t := range tagsToRemove {
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point.RemoveTag(t)
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}
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}
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return in
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}
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func init() {
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processors.Add("tag_limit", func() telegraf.Processor {
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return &TagLimit{}
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})
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}
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