Add filepath processor plugin (#7418)

plugins/processors/filepath/filepath.go

@@ -0,0 +1,150 @@
+package filepath
+
+import (
+	"path/filepath"
+	"strings"
+
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/plugins/processors"
+)
+
+type Options struct {
+	BaseName []BaseOpts `toml:"basename"`
+	DirName  []BaseOpts `toml:"dirname"`
+	Stem     []BaseOpts
+	Clean    []BaseOpts
+	Rel      []RelOpts
+	ToSlash  []BaseOpts `toml:"toslash"`
+}
+
+type ProcessorFunc func(s string) string
+
+// BaseOpts contains options applicable to every function
+type BaseOpts struct {
+	Field string
+	Tag   string
+	Dest  string
+}
+
+type RelOpts struct {
+	BaseOpts
+	BasePath string
+}
+
+const sampleConfig = `
+  ## Treat the tag value as a path and convert it to its last element, storing the result in a new tag 
+  # [[processors.filepath.basename]]
+  #   tag = "path"
+  #   dest = "basepath"
+
+  ## Treat the field value as a path and keep all but the last element of path, typically the path's directory 
+  # [[processors.filepath.dirname]]
+  #   field = "path"
+
+  ## Treat the tag value as a path, converting it to its the last element without its suffix
+  # [[processors.filepath.stem]]
+  #   tag = "path"
+
+  ## Treat the tag value as a path, converting it to the shortest path name equivalent
+  ## to path by purely lexical processing 
+  # [[processors.filepath.clean]]
+  #   tag = "path"
+
+  ## Treat the tag value as a path, converting it to a relative path that is lexically
+  ## equivalent to the source path when joined to 'base_path' 
+  # [[processors.filepath.rel]]
+  #   tag = "path"
+  #   base_path = "/var/log"
+
+  ## Treat the tag value as a path, replacing each separator character in path with a '/' character. Has only
+  ## effect on Windows
+  # [[processors.filepath.toslash]]
+  #   tag = "path"
+`
+
+func (o *Options) SampleConfig() string {
+	return sampleConfig
+}
+
+func (o *Options) Description() string {
+	return "Performs file path manipulations on tags and fields"
+}
+
+// applyFunc applies the specified function to the metric
+func (o *Options) applyFunc(bo BaseOpts, fn ProcessorFunc, metric telegraf.Metric) {
+	if bo.Tag != "" {
+		if v, ok := metric.GetTag(bo.Tag); ok {
+			targetTag := bo.Tag
+
+			if bo.Dest != "" {
+				targetTag = bo.Dest
+			}
+			metric.AddTag(targetTag, fn(v))
+		}
+	}
+
+	if bo.Field != "" {
+		if v, ok := metric.GetField(bo.Field); ok {
+			targetField := bo.Field
+
+			if bo.Dest != "" {
+				targetField = bo.Dest
+			}
+
+			// Only string fields are considered
+			if v, ok := v.(string); ok {
+				metric.AddField(targetField, fn(v))
+			}
+
+		}
+	}
+}
+
+func stemFilePath(path string) string {
+	return strings.TrimSuffix(filepath.Base(path), filepath.Ext(path))
+}
+
+// processMetric processes fields and tag values for a given metric applying the selected transformations
+func (o *Options) processMetric(metric telegraf.Metric) {
+	// Stem
+	for _, v := range o.Stem {
+		o.applyFunc(v, stemFilePath, metric)
+	}
+	// Basename
+	for _, v := range o.BaseName {
+		o.applyFunc(v, filepath.Base, metric)
+	}
+	// Rel
+	for _, v := range o.Rel {
+		o.applyFunc(v.BaseOpts, func(s string) string {
+			relPath, _ := filepath.Rel(v.BasePath, s)
+			return relPath
+		}, metric)
+	}
+	// Dirname
+	for _, v := range o.DirName {
+		o.applyFunc(v, filepath.Dir, metric)
+	}
+	// Clean
+	for _, v := range o.Clean {
+		o.applyFunc(v, filepath.Clean, metric)
+	}
+	// ToSlash
+	for _, v := range o.ToSlash {
+		o.applyFunc(v, filepath.ToSlash, metric)
+	}
+}
+
+func (o *Options) Apply(in ...telegraf.Metric) []telegraf.Metric {
+	for _, m := range in {
+		o.processMetric(m)
+	}
+
+	return in
+}
+
+func init() {
+	processors.Add("filepath", func() telegraf.Processor {
+		return &Options{}
+	})
+}