feat!: Add dynamic name prefix & suffix to reset metric name

docs/CONFIGURATION.md

@@ -376,8 +376,12 @@ Parameters that can be used with any input plugin:
   the name of the input).
 
 - **name_prefix**: Specifies a prefix to attach to the measurement name.
+  If the prefix does not start with a `+` sign, directly overwrites the prefix
+  setting of the metric, otherwise appends it to the front of the prefixed name.
 
 - **name_suffix**: Specifies a suffix to attach to the measurement name.
+  If the suffix does not start with a `+` sign, directly overwrites the suffix
+  setting of the metric, otherwise appends it to the back of the suffixed name.
 
 - **tags**: A map of tags to apply to a specific input's measurements.
 
@@ -461,9 +465,13 @@ Parameters that can be used with any output plugin:
 - **metric_buffer_limit**: The maximum number of unsent metrics to buffer.
   Use this setting to override the agent `metric_buffer_limit` on a per plugin
   basis.
-- **name_override**: Override the original name of the measurement.
-- **name_prefix**: Specifies a prefix to attach to the measurement name.
-- **name_suffix**: Specifies a suffix to attach to the measurement name.
+- **name_override**: Override the original name of the measurement.  (Default is the name of input).
+- **name_prefix**: Specifies a prefix to attach to the measurement name.  (Default is the name prefix of input).
+  If the prefix does not start with a `+` sign, directly overwrites the prefix
+  setting of the metric, otherwise appends it to the front of the prefixed name.
+- **name_suffix**: Specifies a suffix to attach to the measurement name.  (Default is the name suffix of input).
+  If the suffix does not start with a `+` sign, directly overwrites the suffix
+  setting of the metric, otherwise appends it to the back of the suffixed name.
 
 The [metric filtering][] parameters can be used to limit what metrics are
 emitted from the output plugin.
@@ -551,8 +559,14 @@ Parameters that can be used with any aggregator plugin:
   aggregator and will not get sent to the output plugins.
 - **name_override**: Override the base name of the measurement.  (Default is
   the name of the input).
-- **name_prefix**: Specifies a prefix to attach to the measurement name.
-- **name_suffix**: Specifies a suffix to attach to the measurement name.
+- **name_prefix**: Specifies a prefix to attach to the measurement name.  (Default is
+  the name prefix of the input).
+  If the prefix does not start with a `+` sign, directly overwrites the prefix
+  setting of the metric, otherwise appends it to the front of the prefixed name.
+- **name_suffix**: Specifies a suffix to attach to the measurement name.  (Default is
+  the name suffix of the input).
+  If the suffix does not start with a `+` sign, directly overwrites the suffix
+  setting of the metric, otherwise appends it to the back of the suffixed name.
 - **tags**: A map of tags to apply to the measurement - behavior varies based on aggregator.
 
 The [metric filtering][] parameters can be used to limit what metrics are
@@ -806,6 +820,56 @@ select the output.  The tag is removed in the outputs before writing.
     influxdb_database = "other"
 ```
 
+Metrics are prefixed in the input, which is then used to select the output.
+The metric name will be removed/overrode/appended in the outputs before writing.
+
+```toml
+[[inputs.exec]]
+# ...
+name_prefix = "exec1_"
+
+[[inputs.exec]]
+# ...
+name_prefix = "exec2_"
+
+[[inputs.exec]]
+# ...
+name_prefix = "exec3_"
+
+[[inputs.exec]]
+# ...
+name_prefix = "exec4_"
+
+# this will only get exec1
+[[outputs.influxdb]]
+# ...
+namepass = "exec1_*"
+
+# this will only get exec2
+[[outputs.influxdb]]
+# ...
+namepass = "exec2_*"
+# this will remove the previously set prefix
+# so final metric name will be first input name
+name_prefix = ""
+
+# this will only get exec3
+[[outputs.influxdb]]
+# ...
+namepass = "exec3_*"
+# this will override the previously set prefix
+# so final metric name will start with exec3v1_
+name_prefix = "exec3v1_"
+
+# this will only get exec4
+[[outputs.influxdb]]
+# ...
+namepass = "exec4_*"
+# this will appends to the front of the previously set prefix
+# so final metric name will start with telegraf_exec4_
+name_prefix = "+telegraf_"
+```
+
 ## Transport Layer Security (TLS)
 
 Reference the detailed [TLS][] documentation.

metric.go

@@ -1,6 +1,7 @@
 package telegraf
 
 import (
+	"strings"
 	"time"
 )
 
@@ -17,6 +18,48 @@ const (
 	Histogram
 )
 
+type Namer struct {
+	Name   string
+	Prefix string
+	Suffix string
+}
+
+func (n *Namer) Value() string {
+	return n.Prefix + n.Name + n.Suffix
+}
+
+func (n *Namer) SetName(name string) {
+	n.Name = name
+}
+
+// SetPrefix on name, if the prefix does not start with a `+` sign,
+// it directly overwrites the prefix setting of the metric, otherwise add it.
+func (n *Namer) SetPrefix(prefix string) {
+	if strings.HasPrefix(prefix, "+") {
+		n.Prefix = prefix[1:] + n.Prefix
+	} else {
+		n.Prefix = prefix
+	}
+}
+
+// SetSuffix on name, if the suffix does not start with a `+` sign,
+// it directly overwrites the suffix setting of the metric, otherwise add it.
+func (n *Namer) SetSuffix(suffix string) {
+	if strings.HasPrefix(suffix, "+") {
+		n.Suffix += suffix[1:]
+	} else {
+		n.Suffix = suffix
+	}
+}
+
+func (n *Namer) Copy() *Namer {
+	return &Namer{
+		Name:   n.Name,
+		Prefix: n.Prefix,
+		Suffix: n.Suffix,
+	}
+}
+
 // Tag represents a single tag key and value.
 type Tag struct {
 	Key   string
@@ -37,8 +80,16 @@ type Field struct {
 type Metric interface {
 	// Name is the primary identifier for the Metric and corresponds to the
 	// measurement in the InfluxDB data model.
+	// The final name should be m.Name().Value().
+	//
+	// This method is deprecated, use Namer().Value() instead.
 	Name() string
 
+	// Namer is used to fetch the primary identifier for the Metric
+	// and corresponds to the measurement in the InfluxDB data model.
+	// The final name should be m.Namer().Value().
+	Namer() *Namer
+
 	// Tags returns the tags as a map.  This method is deprecated, use TagList instead.
 	Tags() map[string]string
 
@@ -62,20 +113,27 @@ type Metric interface {
 	// might interpret, aggregate the values. Used by prometheus and statsd.
 	Type() ValueType
 
-	// SetName sets the metric name.
+	// SetName sets the metric name
+	// equivalent to m.Namer().SetName(nameOverride).
+	//
+	// This method is deprecated, use Namer().SetName instead.
 	SetName(name string)
 
-	// AddPrefix adds a string to the front of the metric name.  It is
-	// equivalent to m.SetName(prefix + m.Name()).
+	// SetPrefix sets a string to the front of the metric name.  It is
+	// equivalent to m.Namer().SetPrefix(prefix). It is different with
+	// AddPrefix sets a string to the front of the prefixed metric name,
+	// which equivalent to m.Namer().SetPrefix("+" + prefix).
 	//
-	// This method is deprecated, use SetName instead.
-	AddPrefix(prefix string)
+	// This method is deprecated, use Namer().SetPrefix instead.
+	SetPrefix(prefix string)
 
-	// AddSuffix appends a string to the back of the metric name.  It is
-	// equivalent to m.SetName(m.Name() + suffix).
+	// SetSuffix sets a string to the back of the metric name.  It is
+	// equivalent to m.Namer().SetSuffix(suffix). It is different with
+	// AddSuffix sets a string to the back of the suffixed metric name,
+	// which equivalent to m.Namer().SetSuffix("+" + suffix).
 	//
-	// This method is deprecated, use SetName instead.
-	AddSuffix(suffix string)
+	// This method is deprecated, use Namer().SetSuffix instead.
+	SetSuffix(suffix string)
 
 	// GetTag returns the value of a tag and a boolean to indicate if it was set.
 	GetTag(key string) (string, bool)

metric/metric.go

@@ -10,7 +10,7 @@ import (
 )
 
 type metric struct {
-	name   string
+	namer  *telegraf.Namer
 	tags   []*telegraf.Tag
 	fields []*telegraf.Field
 	tm     time.Time
@@ -24,6 +24,16 @@ func New(
 	fields map[string]interface{},
 	tm time.Time,
 	tp ...telegraf.ValueType,
+) telegraf.Metric {
+	return FromNamer(telegraf.Namer{Name: name}, tags, fields, tm, tp...)
+}
+
+func FromNamer(
+	namer telegraf.Namer,
+	tags map[string]string,
+	fields map[string]interface{},
+	tm time.Time,
+	tp ...telegraf.ValueType,
 ) telegraf.Metric {
 	var vtype telegraf.ValueType
 	if len(tp) > 0 {
@@ -33,7 +43,7 @@ func New(
 	}
 
 	m := &metric{
-		name:   name,
+		namer:  &namer,
 		tags:   nil,
 		fields: nil,
 		tm:     tm,
@@ -67,7 +77,7 @@ func New(
 // removed.
 func FromMetric(other telegraf.Metric) telegraf.Metric {
 	m := &metric{
-		name:   other.Name(),
+		namer:  other.Namer(),
 		tags:   make([]*telegraf.Tag, len(other.TagList())),
 		fields: make([]*telegraf.Field, len(other.FieldList())),
 		tm:     other.Time(),
@@ -85,11 +95,15 @@ func FromMetric(other telegraf.Metric) telegraf.Metric {
 }
 
 func (m *metric) String() string {
-	return fmt.Sprintf("%s %v %v %d", m.name, m.Tags(), m.Fields(), m.tm.UnixNano())
+	return fmt.Sprintf("%s %v %v %d", m.Name(), m.Tags(), m.Fields(), m.tm.UnixNano())
 }
 
 func (m *metric) Name() string {
-	return m.name
+	return m.namer.Value()
+}
+
+func (m *metric) Namer() *telegraf.Namer {
+	return m.namer
 }
 
 func (m *metric) Tags() map[string]string {
@@ -126,15 +140,15 @@ func (m *metric) Type() telegraf.ValueType {
 }
 
 func (m *metric) SetName(name string) {
-	m.name = name
+	m.namer.SetName(name)
 }
 
-func (m *metric) AddPrefix(prefix string) {
-	m.name = prefix + m.name
+func (m *metric) SetPrefix(prefix string) {
+	m.namer.SetPrefix(prefix)
 }
 
-func (m *metric) AddSuffix(suffix string) {
-	m.name = m.name + suffix
+func (m *metric) SetSuffix(suffix string) {
+	m.namer.SetSuffix(suffix)
 }
 
 func (m *metric) AddTag(key, value string) {
@@ -243,7 +257,7 @@ func (m *metric) SetTime(t time.Time) {
 
 func (m *metric) Copy() telegraf.Metric {
 	m2 := &metric{
-		name:   m.name,
+		namer:  m.namer.Copy(),
 		tags:   make([]*telegraf.Tag, len(m.tags)),
 		fields: make([]*telegraf.Field, len(m.fields)),
 		tm:     m.tm,
@@ -262,7 +276,7 @@ func (m *metric) Copy() telegraf.Metric {
 
 func (m *metric) HashID() uint64 {
 	h := fnv.New64a()
-	h.Write([]byte(m.name))
+	h.Write([]byte(m.Name()))
 	h.Write([]byte("\n"))
 	for _, tag := range m.tags {
 		h.Write([]byte(tag.Key))

metric/metric_test.go

@@ -299,20 +299,38 @@ func TestSetName(t *testing.T) {
 	require.Equal(t, "foo", m.Name())
 }
 
+func TestSetPrefix(t *testing.T) {
+	m := baseMetric()
+	m.SetPrefix("foo_")
+	require.Equal(t, "foo_cpu", m.Name())
+	m.Namer().SetPrefix("bar_")
+	require.Equal(t, "bar_cpu", m.Name())
+}
+
+func TestSetSuffix(t *testing.T) {
+	m := baseMetric()
+	m.Namer().SetSuffix("_foo")
+	require.Equal(t, "cpu_foo", m.Name())
+	m.Namer().SetSuffix("_bar")
+	require.Equal(t, "cpu_bar", m.Name())
+}
+
 func TestAddPrefix(t *testing.T) {
 	m := baseMetric()
-	m.AddPrefix("foo_")
+	m.SetPrefix("foo_")
 	require.Equal(t, "foo_cpu", m.Name())
-	m.AddPrefix("foo_")
-	require.Equal(t, "foo_foo_cpu", m.Name())
+	// append to the front of foo_cpu
+	m.Namer().SetPrefix("+bar_")
+	require.Equal(t, "bar_foo_cpu", m.Name())
 }
 
 func TestAddSuffix(t *testing.T) {
 	m := baseMetric()
-	m.AddSuffix("_foo")
+	m.Namer().SetSuffix("_foo")
 	require.Equal(t, "cpu_foo", m.Name())
-	m.AddSuffix("_foo")
-	require.Equal(t, "cpu_foo_foo", m.Name())
+	// append to the back of cpu_bar
+	m.Namer().SetSuffix("+_bar")
+	require.Equal(t, "cpu_foo_bar", m.Name())
 }
 
 func TestValueType(t *testing.T) {

models/makemetric.go

@@ -14,15 +14,15 @@ func makemetric(
 	tags map[string]string,
 	globalTags map[string]string,
 ) telegraf.Metric {
+	namer := metric.Namer()
 	if len(nameOverride) != 0 {
-		metric.SetName(nameOverride)
+		namer.SetName(nameOverride)
 	}
-
 	if len(namePrefix) != 0 {
-		metric.AddPrefix(namePrefix)
+		namer.SetPrefix(namePrefix)
 	}
 	if len(nameSuffix) != 0 {
-		metric.AddSuffix(nameSuffix)
+		namer.SetSuffix(nameSuffix)
 	}
 
 	// Apply plugin-wide tags

models/running_input_test.go

@@ -209,7 +209,7 @@ func TestMakeMetricNamePrefix(t *testing.T) {
 		now,
 		telegraf.Untyped)
 	m = ri.MakeMetric(m)
-	expected := metric.New("foobar_RITest",
+	expected := metric.FromNamer(telegraf.Namer{Name: "RITest", Prefix: "foobar_"},
 		nil,
 		map[string]interface{}{
 			"value": 101,
@@ -234,7 +234,7 @@ func TestMakeMetricNameSuffix(t *testing.T) {
 		now,
 		telegraf.Untyped)
 	m = ri.MakeMetric(m)
-	expected := metric.New("RITest_foobar",
+	expected := metric.FromNamer(telegraf.Namer{Name: "RITest", Suffix: "_foobar"},
 		nil,
 		map[string]interface{}{
 			"value": 101,