Add override processor (#3773)

This plugin can perform the standard metric modifications using override semantics.
This commit is contained in:
Karsten Schnitter 2018-03-07 22:27:43 +01:00 committed by Daniel Nelson
parent 64c1a7a860
commit 82d224d9e2
4 changed files with 171 additions and 0 deletions

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package all
import (
_ "github.com/influxdata/telegraf/plugins/processors/override"
_ "github.com/influxdata/telegraf/plugins/processors/printer"
)

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# Override Processor Plugin
The override processor plugin allows overriding all modifications that are
supported by input plugins and aggregators:
* name_override
* name_prefix
* name_suffix
* tags
All metrics passing through this processor will be modified accordingly. Values
of *name_override*, *name_prefix*, *name_suffix* and already present *tags* with
conflicting keys will be overwritten. Absent *tags* will be created.
Use-case of this plugin encompass ensuring certain tags or naming conventions
are adhered to irrespective of input plugin configurations, e.g. by
`taginclude`.
### Configuration:
```toml
# Add a global tag to all metrics
[[processors.override]]
name_override = "new name_override"
name_prefix = "new name_prefix"
name_suffix = ":new name_suffix"
[processors.tags.add]
additional_tag = "tag_value"
existing_tag = "new tag_value"
```

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package override
import (
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/plugins/processors"
)
var sampleConfig = `
## NOTE This processor will override names, name prefixes, name suffixes and
## values of tags, that are already present in the metric passed through this
## filter.
## All modifications on inputs and aggregators can be overridden:
# name_override = "new name"
# name_prefix = "new name_prefix"
# name_suffix = "new name_suffix"
## Tags to be added (all values must be strings)
# [processors.overide.tags]
# additional_tag = "tag_value"
`
type Override struct {
NameOverride string
NamePrefix string
NameSuffix string
Tags map[string]string
}
func (p *Override) SampleConfig() string {
return sampleConfig
}
func (p *Override) Description() string {
return "Add all configured tags to all metrics that pass through this filter."
}
func (p *Override) Apply(in ...telegraf.Metric) []telegraf.Metric {
for _, metric := range in {
if len(p.NameOverride) > 0 {
metric.SetName(p.NameOverride)
}
if len(p.NamePrefix) > 0 {
metric.SetPrefix(p.NamePrefix)
}
if len(p.NameSuffix) > 0 {
metric.SetSuffix(p.NameSuffix)
}
for key, value := range p.Tags {
metric.AddTag(key, value)
}
}
return in
}
func init() {
processors.Add("override", func() telegraf.Processor {
return &Override{}
})
}

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package override
import (
"testing"
"time"
"github.com/influxdata/telegraf"
"github.com/influxdata/telegraf/metric"
"github.com/stretchr/testify/assert"
)
func createTestMetric() telegraf.Metric {
metric, _ := metric.New("m1",
map[string]string{"metric_tag": "from_metric"},
map[string]interface{}{"value": int64(1)},
time.Now(),
)
return metric
}
func calculateProcessedTags(processor Override, metric telegraf.Metric) map[string]string {
processed := processor.Apply(metric)
return processed[0].Tags()
}
func TestRetainsTags(t *testing.T) {
processor := Override{}
tags := calculateProcessedTags(processor, createTestMetric())
value, present := tags["metric_tag"]
assert.True(t, present, "Tag of metric was not present")
assert.Equal(t, "from_metric", value, "Value of Tag was changed")
}
func TestAddTags(t *testing.T) {
processor := Override{Tags: map[string]string{"added_tag": "from_config", "another_tag": ""}}
tags := calculateProcessedTags(processor, createTestMetric())
value, present := tags["added_tag"]
assert.True(t, present, "Additional Tag of metric was not present")
assert.Equal(t, "from_config", value, "Value of Tag was changed")
assert.Equal(t, 3, len(tags), "Should have one previous and two added tags.")
}
func TestOverwritesPresentTagValues(t *testing.T) {
processor := Override{Tags: map[string]string{"metric_tag": "from_config"}}
tags := calculateProcessedTags(processor, createTestMetric())
value, present := tags["metric_tag"]
assert.True(t, present, "Tag of metric was not present")
assert.Equal(t, 1, len(tags), "Should only have one tag.")
assert.Equal(t, "from_config", value, "Value of Tag was not changed")
}
func TestOverridesName(t *testing.T) {
processor := Override{NameOverride: "overridden"}
processed := processor.Apply(createTestMetric())
assert.Equal(t, "overridden", processed[0].Name(), "Name was not overridden")
}
func TestNamePrefix(t *testing.T) {
processor := Override{NamePrefix: "Pre-"}
processed := processor.Apply(createTestMetric())
assert.Equal(t, "Pre-m1", processed[0].Name(), "Prefix was not applied")
}
func TestNameSuffix(t *testing.T) {
processor := Override{NameSuffix: "-suff"}
processed := processor.Apply(createTestMetric())
assert.Equal(t, "m1-suff", processed[0].Name(), "Suffix was not applied")
}