From 75228cf8bf78ca66705de1ead6f2a4c77150852b Mon Sep 17 00:00:00 2001
From: Julian Kornberger <jk+github@digineo.de>
Date: Mon, 3 Oct 2016 19:56:02 +0200
Subject: [PATCH] Add importer for global RRD stats

---
 main.go    | 24 ++++++++++++++++++++
 rrd/rrd.go | 66 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 90 insertions(+)
 create mode 100644 rrd/rrd.go

diff --git a/main.go b/main.go
index 10e4838..fcffe3b 100644
--- a/main.go
+++ b/main.go
@@ -17,6 +17,7 @@ import (
 	"github.com/FreifunkBremen/respond-collector/database"
 	"github.com/FreifunkBremen/respond-collector/models"
 	"github.com/FreifunkBremen/respond-collector/respond"
+	"github.com/FreifunkBremen/respond-collector/rrd"
 )
 
 var (
@@ -28,12 +29,19 @@ var (
 )
 
 func main() {
+	var importPath string
+	flag.StringVar(&importPath, "import", "", "import global statistics from the given RRD file, requires influxdb")
 	flag.StringVar(&configFile, "config", "config.yml", "path of configuration file (default:config.yaml)")
 	flag.Parse()
 	config = models.ReadConfigFile(configFile)
 
 	if config.Influxdb.Enable {
 		db = database.New(config)
+
+		if importPath != "" {
+			importRRD(importPath)
+			os.Exit(0)
+		}
 	}
 
 	nodes = models.NewNodes(config)
@@ -74,3 +82,19 @@ func main() {
 		db.Close()
 	}
 }
+
+func importRRD(path string) {
+	log.Println("importing RRD from", path)
+	for ds := range rrd.Read(path) {
+		db.AddPoint(
+			database.MeasurementGlobal,
+			nil,
+			map[string]interface{}{
+				"nodes":         ds.Nodes,
+				"clients.total": ds.Clients,
+			},
+			ds.Time,
+		)
+	}
+	db.Close()
+}
diff --git a/rrd/rrd.go b/rrd/rrd.go
new file mode 100644
index 0000000..160166f
--- /dev/null
+++ b/rrd/rrd.go
@@ -0,0 +1,66 @@
+// Importer for global RRD stats
+package rrd
+
+import (
+	"bufio"
+	"io"
+	"os/exec"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+)
+
+var linePattern = regexp.MustCompile("^<!-- ....-..-.. ..:..:.. [A-Z]+ / (\\d+) --> <row><v>([^<]+)</v><v>([^<]+)</v></row>")
+
+type Dataset struct {
+	Time    time.Time
+	Nodes   float64
+	Clients float64
+}
+
+func Read(rrdFile string) chan Dataset {
+	out := make(chan Dataset)
+	cmd := exec.Command("rrdtool", "dump", rrdFile)
+	stdout, err := cmd.StdoutPipe()
+
+	if err != nil {
+		panic(err)
+	}
+	if err := cmd.Start(); err != nil {
+		panic(err)
+	}
+
+	r := bufio.NewReader(stdout)
+	found := false
+
+	go func() {
+		for {
+			// Read stdout by line
+			line, _, err := r.ReadLine()
+			if err == io.EOF {
+				break
+			}
+			str := strings.TrimSpace(string(line))
+
+			// Search for the start of the daily datasets
+			if !found {
+				found = strings.Contains(str, "<!-- 86400 seconds -->")
+				continue
+			}
+			if matches := linePattern.FindStringSubmatch(str); matches != nil && matches[2] != "NaN" {
+				seconds, _ := strconv.Atoi(matches[1])
+				nodes, _ := strconv.ParseFloat(matches[2], 64)
+				clients, _ := strconv.ParseFloat(matches[2], 64)
+
+				out <- Dataset{
+					Time:    time.Unix(int64(seconds), 0),
+					Nodes:   nodes,
+					Clients: clients,
+				}
+			}
+		}
+		close(out)
+	}()
+	return out
+}