filestat input plugin

closes #929

CHANGELOG.md

@@ -39,6 +39,7 @@ based on _prefix_ in addition to globs. This means that a filter like
 - [#1056](https://github.com/influxdata/telegraf/pull/1056): Don't allow inputs to overwrite host tags.
 - [#1035](https://github.com/influxdata/telegraf/issues/1035): Add `user`, `exe`, `pidfile` tags to procstat plugin.
 - [#1041](https://github.com/influxdata/telegraf/issues/1041): Add `n_cpus` field to the system plugin.
+- [#1072](https://github.com/influxdata/telegraf/pull/1072): New Input Plugin: filestat.
 
 ### Bugfixes
 

etc/telegraf.conf

@@ -580,6 +580,16 @@
 #   data_format = "influx"
 
 
+# # Read stats about given file(s)
+# [[inputs.filestat]]
+#   ## Files to gather stats about.
+#   ## These accept standard unix glob matching rules, but with the addition of
+#   ## ** as a "super asterisk". See https://github.com/gobwas/glob.
+#   ["/etc/telegraf/telegraf.conf", "/var/log/**.log"]
+#   ## If true, read the entire file and calculate an md5 checksum.
+#   md5 = false
+
+
 # # Read metrics of haproxy, via socket or csv stats page
 # [[inputs.haproxy]]
 #   ## An array of address to gather stats about. Specify an ip on hostname

plugins/inputs/all/all.go

@@ -14,6 +14,7 @@ import (
 	_ "github.com/influxdata/telegraf/plugins/inputs/dovecot"
 	_ "github.com/influxdata/telegraf/plugins/inputs/elasticsearch"
 	_ "github.com/influxdata/telegraf/plugins/inputs/exec"
+	_ "github.com/influxdata/telegraf/plugins/inputs/filestat"
 	_ "github.com/influxdata/telegraf/plugins/inputs/github_webhooks"
 	_ "github.com/influxdata/telegraf/plugins/inputs/haproxy"
 	_ "github.com/influxdata/telegraf/plugins/inputs/http_response"

plugins/inputs/filestat/README.md

@@ -0,0 +1,38 @@
+# filestat Input Plugin
+
+The filestat plugin gathers metrics about file existence, size, and other stats.
+
+### Configuration:
+
+```toml
+# Read stats about given file(s)
+[[inputs.filestat]]
+  ## Files to gather stats about.
+  ## These accept standard unix glob matching rules, but with the addition of
+  ## ** as a "super asterisk". See https://github.com/gobwas/glob.
+  files = ["/etc/telegraf/telegraf.conf", "/var/log/**.log"]
+  ## If true, read the entire file and calculate an md5 checksum.
+  md5 = false
+```
+
+### Measurements & Fields:
+
+- filestat
+    - exists (int, 0 | 1)
+    - size_bytes (int, bytes)
+    - mode (string)
+    - md5 (optional, string)
+
+### Tags:
+
+- All measurements have the following tags:
+    - file (the path the to file, as specified in the config)
+
+### Example Output:
+
+```
+$ telegraf -config /etc/telegraf/telegraf.conf -input-filter filestat -test
+* Plugin: filestat, Collection 1
+> filestat,file=/tmp/foo/bar,host=tyrion exists=0i 1461203374493128216
+> filestat,file=/Users/sparrc/ws/telegraf.conf,host=tyrion exists=1i,mode="-rw-r--r--",size=47894i 1461203374493199335
+```

plugins/inputs/filestat/filestat.go

@@ -0,0 +1,186 @@
+package filestat
+
+import (
+	"crypto/md5"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/gobwas/glob"
+
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/plugins/inputs"
+)
+
+var sepStr = fmt.Sprintf("%v", string(os.PathSeparator))
+
+const sampleConfig = `
+  ## Files to gather stats about.
+  ## These accept standard unix glob matching rules, but with the addition of
+  ## ** as a "super asterisk". See https://github.com/gobwas/glob.
+  ["/etc/telegraf/telegraf.conf", "/var/log/**.log"]
+  ## If true, read the entire file and calculate an md5 checksum.
+  md5 = false
+`
+
+type FileStat struct {
+	Md5   bool
+	Files []string
+
+	// maps full file paths to glob obj
+	globs map[string]glob.Glob
+	// maps full file paths to their root dir
+	roots map[string]string
+}
+
+func NewFileStat() *FileStat {
+	return &FileStat{
+		globs: make(map[string]glob.Glob),
+		roots: make(map[string]string),
+	}
+}
+
+func (_ *FileStat) Description() string {
+	return "Read stats about given file(s)"
+}
+
+func (_ *FileStat) SampleConfig() string { return sampleConfig }
+
+func (f *FileStat) Gather(acc telegraf.Accumulator) error {
+	var errS string
+	var err error
+
+	for _, filepath := range f.Files {
+		// Get the compiled glob object for this filepath
+		g, ok := f.globs[filepath]
+		if !ok {
+			if g, err = glob.Compile(filepath, os.PathSeparator); err != nil {
+				errS += err.Error() + " "
+				continue
+			}
+			f.globs[filepath] = g
+		}
+		// Get the root directory for this filepath
+		root, ok := f.roots[filepath]
+		if !ok {
+			root = findRootDir(filepath)
+			f.roots[filepath] = root
+		}
+
+		var matches []string
+		// Do not walk file tree if we don't have to.
+		if !hasMeta(filepath) {
+			matches = []string{filepath}
+		} else {
+			matches = walkFilePath(f.roots[filepath], f.globs[filepath])
+		}
+		for _, file := range matches {
+			tags := map[string]string{
+				"file": file,
+			}
+			fields := map[string]interface{}{
+				"exists": int64(0),
+			}
+			// Get file stats
+			fileInfo, err := os.Stat(file)
+			if os.IsNotExist(err) {
+				// file doesn't exist, so move on to the next
+				acc.AddFields("filestat", fields, tags)
+				continue
+			}
+			if err != nil {
+				errS += err.Error() + " "
+				continue
+			}
+
+			// file exists and no errors encountered
+			fields["exists"] = int64(1)
+			fields["size_bytes"] = fileInfo.Size()
+			fields["mode"] = fileInfo.Mode().String()
+
+			if f.Md5 {
+				md5, err := getMd5(file)
+				if err != nil {
+					errS += err.Error() + " "
+				} else {
+					fields["md5_sum"] = md5
+				}
+			}
+
+			acc.AddFields("filestat", fields, tags)
+		}
+	}
+
+	if errS != "" {
+		return fmt.Errorf(errS)
+	}
+	return nil
+}
+
+// walk the filepath from the given root and return a list of files that match
+// the given glob.
+func walkFilePath(root string, g glob.Glob) []string {
+	matchedFiles := []string{}
+	walkfn := func(path string, _ os.FileInfo, _ error) error {
+		if g.Match(path) {
+			matchedFiles = append(matchedFiles, path)
+		}
+		return nil
+	}
+	filepath.Walk(root, walkfn)
+	return matchedFiles
+}
+
+// Read given file and calculate an md5 hash.
+func getMd5(file string) (string, error) {
+	of, err := os.Open(file)
+	if err != nil {
+		return "", err
+	}
+	defer of.Close()
+
+	hash := md5.New()
+	_, err = io.Copy(hash, of)
+	if err != nil {
+		// fatal error
+		return "", err
+	}
+	return fmt.Sprintf("%x", hash.Sum(nil)), nil
+}
+
+// find the root dir of the given path (could include globs).
+// ie:
+//   /var/log/telegraf.conf -> /var/log/
+//   /home/** ->               /home/
+//   /home/*/** ->             /home/
+//   /lib/share/*/*/**.txt ->  /lib/share/
+func findRootDir(path string) string {
+	pathItems := strings.Split(path, sepStr)
+	outpath := sepStr
+	for i, item := range pathItems {
+		if i == len(pathItems)-1 {
+			break
+		}
+		if item == "" {
+			continue
+		}
+		if hasMeta(item) {
+			break
+		}
+		outpath += item + sepStr
+	}
+	return outpath
+}
+
+// hasMeta reports whether path contains any magic glob characters.
+func hasMeta(path string) bool {
+	return strings.IndexAny(path, "*?[") >= 0
+}
+
+func init() {
+	inputs.Add("filestat", func() telegraf.Input {
+		return NewFileStat()
+	})
+}