rename spaces to underscore, add snakecase option

plugins/inputs/ethtool/README.md

@@ -16,10 +16,11 @@ The ethtool input plugin pulls ethernet device stats. Fields pulled will depend
   ## Some drivers declare statistics with extra whitespace, different spacing,
   ## and mix cases. This list, when enabled, can be used to clean the keys.
   ## Here are the current possible normalizations:
+  ##  * snakecase: converts camelCaseWords to camel_case_words
   ##  * trim: removes leading and trailing whitespace
   ##  * lower: changes all capitalized letters to lowercase
-  ##  * spaces: replaces spaces with underscores
-  # normalize_keys = ["trim", "lower", "spaces"]
+  ##  * underscore: replaces spaces with underscores
+  # normalize_keys = ["snakecase", "trim", "lower", "underscore"]
 ```
 
 Interfaces can be included or ignored using:

plugins/inputs/ethtool/ethtool.go

@@ -45,10 +45,11 @@ const (
   ## Some drivers declare statistics with extra whitespace, different spacing,
   ## and mix cases. This list, when enabled, can be used to clean the keys.
   ## Here are the current possible normalizations:
+  ##  * snakecase: converts camelCaseWords to camel_case_words
   ##  * trim: removes leading and trailing whitespace
   ##  * lower: changes all capitalized letters to lowercase
-  ##  * spaces: replaces spaces with underscores
-  # normalize_keys = ["trim", "lower", "spaces"]
+  ##  * underscore: replaces spaces with underscores
+  # normalize_keys = ["snakecase", "trim", "lower", "underscore"]
 `
 )
 

plugins/inputs/ethtool/ethtool_linux.go

@@ -5,6 +5,7 @@ package ethtool
 
 import (
 	"net"
+	"regexp"
 	"strings"
 	"sync"
 
@@ -89,21 +90,36 @@ func (e *Ethtool) gatherEthtoolStats(iface net.Interface, acc telegraf.Accumulat
 }
 
 // normalize key string; order matters to avoid replacing whitespace with
-// underscores, then trying to trim those same underscores.
+// underscores, then trying to trim those same underscores. Likewise with
+// camelcase before trying to lower case things.
 func (e *Ethtool) normalizeKey(key string) string {
+	// must trim whitespace or this will have a leading _
+	if inStringSlice(e.NormalizeKeys, "snakecase") {
+		key = camelCase2SnakeCase(strings.TrimSpace(key))
+	}
+	// must occur before underscore, otherwise nothing to trim
 	if inStringSlice(e.NormalizeKeys, "trim") {
 		key = strings.TrimSpace(key)
 	}
 	if inStringSlice(e.NormalizeKeys, "lower") {
 		key = strings.ToLower(key)
 	}
-	if inStringSlice(e.NormalizeKeys, "spaces") {
+	if inStringSlice(e.NormalizeKeys, "underscore") {
 		key = strings.ReplaceAll(key, " ", "_")
 	}
 
 	return key
 }
 
+func camelCase2SnakeCase(value string) string {
+	matchFirstCap := regexp.MustCompile("(.)([A-Z][a-z]+)")
+	matchAllCap := regexp.MustCompile("([a-z0-9])([A-Z])")
+
+	snake := matchFirstCap.ReplaceAllString(value, "${1}_${2}")
+	snake = matchAllCap.ReplaceAllString(snake, "${1}_${2}")
+	return strings.ToLower(snake)
+}
+
 func inStringSlice(slice []string, value string) bool {
 	for _, item := range slice {
 		if item == value {

plugins/inputs/ethtool/ethtool_test.go

@@ -390,7 +390,7 @@ type TestCase struct {
 func TestNormalizedKeys(t *testing.T) {
 	cases := []TestCase{
 		{
-			normalization: []string{"spaces"},
+			normalization: []string{"underscore"},
 			stats: map[string]uint64{
 				"port rx":      1,
 				" Port_tx":     0,
@@ -403,7 +403,7 @@ func TestNormalizedKeys(t *testing.T) {
 			},
 		},
 		{
-			normalization: []string{"spaces", "lower"},
+			normalization: []string{"underscore", "lower"},
 			stats: map[string]uint64{
 				"Port rx":      1,
 				" Port_tx":     0,
@@ -416,7 +416,7 @@ func TestNormalizedKeys(t *testing.T) {
 			},
 		},
 		{
-			normalization: []string{"spaces", "lower", "trim"},
+			normalization: []string{"underscore", "lower", "trim"},
 			stats: map[string]uint64{
 				"  Port RX ":   1,
 				" Port_tx":     0,
@@ -428,6 +428,32 @@ func TestNormalizedKeys(t *testing.T) {
 				"interface_up": 0,
 			},
 		},
+		{
+			normalization: []string{"underscore", "lower", "snakecase", "trim"},
+			stats: map[string]uint64{
+				"  Port RX ":   1,
+				" Port_tx":     0,
+				"interface_up": 0,
+			},
+			expectedFields: map[string]uint64{
+				"port_rx":      1,
+				"port_tx":      0,
+				"interface_up": 0,
+			},
+		},
+		{
+			normalization: []string{"snakecase"},
+			stats: map[string]uint64{
+				"  PortRX ":    1,
+				" PortTX":      0,
+				"interface_up": 0,
+			},
+			expectedFields: map[string]uint64{
+				"port_rx":      1,
+				"port_tx":      0,
+				"interface_up": 0,
+			},
+		},
 		{
 			normalization: []string{},
 			stats: map[string]uint64{
@@ -466,6 +492,7 @@ func TestNormalizedKeys(t *testing.T) {
 		assert.NoError(t, err)
 		assert.Len(t, acc.Metrics, 1)
 
+		acc.AssertContainsFields(t, pluginName, toStringMapInterface(c.expectedFields))
 		acc.AssertContainsTaggedFields(t, pluginName, toStringMapInterface(c.expectedFields), expectedTags)
 	}
 }