Add rename processor (#4528)

README.md

@@ -279,6 +279,7 @@ formats may be used with input plugins supporting the `data_format` option:
 * [override](./plugins/processors/override)
 * [printer](./plugins/processors/printer)
 * [regex](./plugins/processors/regex)
+* [rename](./plugins/processors/rename)
 * [topk](./plugins/processors/topk)
 
 ## Aggregator Plugins

plugins/processors/all/all.go

@@ -6,5 +6,6 @@ import (
 	_ "github.com/influxdata/telegraf/plugins/processors/override"
 	_ "github.com/influxdata/telegraf/plugins/processors/printer"
 	_ "github.com/influxdata/telegraf/plugins/processors/regex"
+	_ "github.com/influxdata/telegraf/plugins/processors/rename"
 	_ "github.com/influxdata/telegraf/plugins/processors/topk"
 )

plugins/processors/rename/README.md

@@ -0,0 +1,41 @@
+# Rename Processor Plugin
+
+The `rename` processor renames measurements, fields, and tags.
+
+### Configuration:
+
+```toml
+## Measurement, tag, and field renamings are stored in separate sub-tables.
+## Specify one sub-table per rename operation.
+[[processors.rename]]
+[[processors.rename.measurement]]
+  ## measurement to change
+  from = "network_interface_throughput"
+  to = "throughput"
+
+[[processors.rename.tag]]
+  ## tag to change
+  from = "hostname"
+  to = "host"
+
+[[processors.rename.field]]
+  ## field to change
+  from = "lower"
+  to = "min"
+
+[[processors.rename.field]]
+  ## field to change
+  from = "upper"
+  to = "max"
+```
+
+### Tags:
+
+No tags are applied by this processor, though it can alter them by renaming.
+
+### Example processing:
+
+```diff
+- network_interface_throughput,hostname=backend.example.com,units=kbps lower=10i,upper=1000i,mean=500i 1502489900000000000
++ throughput,host=backend.example.com,units=kbps min=10i,max=1000i,mean=500i 1502489900000000000
+```

plugins/processors/rename/rename.go

@@ -0,0 +1,82 @@
+package rename
+
+import (
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/plugins/processors"
+)
+
+const sampleConfig = `
+  ## Measurement, tag, and field renamings are stored in separate sub-tables.
+  ## Specify one sub-table per rename operation.
+  # [[processors.rename.measurement]]
+  #   ## measurement to change
+  #   from = "kilobytes_per_second"
+  #   to = "kbps"
+
+  # [[processors.rename.tag]]
+  #   ## tag to change
+  #   from = "host"
+  #   to = "hostname"
+
+  # [[processors.rename.field]]
+  #   ## field to change
+  #   from = "lower"
+  #   to = "min"
+
+  # [[processors.rename.field]]
+  #   ## field to change
+  #   from = "upper"
+  #   to = "max"
+`
+
+type renamer struct {
+	From string
+	To   string
+}
+
+type Rename struct {
+	Measurement []renamer
+	Tag         []renamer
+	Field       []renamer
+}
+
+func (r *Rename) SampleConfig() string {
+	return sampleConfig
+}
+
+func (r *Rename) Description() string {
+	return "Rename measurements, tags, and fields that pass through this filter."
+}
+
+func (r *Rename) Apply(in ...telegraf.Metric) []telegraf.Metric {
+	for _, point := range in {
+		for _, measurementRenamer := range r.Measurement {
+			if point.Name() == measurementRenamer.From {
+				point.SetName(measurementRenamer.To)
+				break
+			}
+		}
+
+		for _, tagRenamer := range r.Tag {
+			if value, ok := point.GetTag(tagRenamer.From); ok {
+				point.RemoveTag(tagRenamer.From)
+				point.AddTag(tagRenamer.To, value)
+			}
+		}
+
+		for _, fieldRenamer := range r.Field {
+			if value, ok := point.GetField(fieldRenamer.From); ok {
+				point.RemoveField(fieldRenamer.From)
+				point.AddField(fieldRenamer.To, value)
+			}
+		}
+	}
+
+	return in
+}
+
+func init() {
+	processors.Add("rename", func() telegraf.Processor {
+		return &Rename{}
+	})
+}

plugins/processors/rename/rename_test.go

@@ -0,0 +1,58 @@
+package rename
+
+import (
+	"testing"
+	"time"
+
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/metric"
+	"github.com/stretchr/testify/assert"
+)
+
+func newMetric(name string, tags map[string]string, fields map[string]interface{}) telegraf.Metric {
+	if tags == nil {
+		tags = map[string]string{}
+	}
+	if fields == nil {
+		fields = map[string]interface{}{}
+	}
+	m, _ := metric.New(name, tags, fields, time.Now())
+	return m
+}
+
+func TestMeasurementRename(t *testing.T) {
+	r := Rename{}
+	r.Measurement = []renamer{
+		{From: "foo", To: "bar"},
+		{From: "baz", To: "quux"},
+	}
+	m1 := newMetric("foo", nil, nil)
+	m2 := newMetric("bar", nil, nil)
+	m3 := newMetric("baz", nil, nil)
+	results := r.Apply(m1, m2, m3)
+	assert.Equal(t, "bar", results[0].Name(), "Should change name from 'foo' to 'bar'")
+	assert.Equal(t, "bar", results[1].Name(), "Should not name from 'bar'")
+	assert.Equal(t, "quux", results[2].Name(), "Should change name from 'baz' to 'quux'")
+}
+
+func TestTagRename(t *testing.T) {
+	r := Rename{}
+	r.Tag = []renamer{
+		{From: "hostname", To: "host"},
+	}
+	m := newMetric("foo", map[string]string{"hostname": "localhost", "region": "east-1"}, nil)
+	results := r.Apply(m)
+
+	assert.Equal(t, map[string]string{"host": "localhost", "region": "east-1"}, results[0].Tags(), "should change tag 'hostname' to 'host'")
+}
+
+func TestFieldRename(t *testing.T) {
+	r := Rename{}
+	r.Field = []renamer{
+		{From: "time_msec", To: "time"},
+	}
+	m := newMetric("foo", nil, map[string]interface{}{"time_msec": int64(1250), "snakes": true})
+	results := r.Apply(m)
+
+	assert.Equal(t, map[string]interface{}{"time": int64(1250), "snakes": true}, results[0].Fields(), "should change field 'time_msec' to 'time'")
+}