Add ethtool input plugin (#5865)

plugins/inputs/ethtool/ethtool.go

@@ -0,0 +1,46 @@
+package ethtool
+
+import (
+	"net"
+)
+
+type Command interface {
+	Init() error
+	DriverName(intf string) (string, error)
+	Interfaces() ([]net.Interface, error)
+	Stats(intf string) (map[string]uint64, error)
+}
+
+type Ethtool struct {
+	// This is the list of interface names to include
+	InterfaceInclude []string `toml:"interface_include"`
+
+	// This is the list of interface names to ignore
+	InterfaceExclude []string `toml:"interface_exclude"`
+
+	// the ethtool command
+	command Command
+}
+
+const (
+	pluginName    = "ethtool"
+	tagInterface  = "interface"
+	tagDriverName = "driver"
+
+	sampleConfig = `
+  ## List of interfaces to pull metrics for
+  # interface_include = ["eth0"]
+
+  ## List of interfaces to ignore when pulling metrics.
+  # interface_exclude = ["eth1"]
+`
+)
+
+func (e *Ethtool) SampleConfig() string {
+	return sampleConfig
+}
+
+// Description returns a one-sentence description on the Input
+func (e *Ethtool) Description() string {
+	return "Returns ethtool statistics for given interfaces"
+}