From: Sebastian Harl <sh@tokkee.org>
Date: Fri, 21 Nov 2014 20:23:57 +0000 (+0100)
Subject: Added support for simple SVG graphs for metrics.
X-Git-Url: https://git.tokkee.org/?a=commitdiff_plain;h=16dddfceb2e1918a4db62f70d0aa7aef03045fc0;p=sysdb%2Fwebui.git

Added support for simple SVG graphs for metrics.

The graph will be displayed when querying a metric. The graph itself mostly
uses default settings of the Plotinum package for now.
---

diff --git a/server/graph.go b/server/graph.go
new file mode 100644
index 0000000..054fe8e
--- /dev/null
+++ b/server/graph.go
@@ -0,0 +1,105 @@
+//
+// Copyright (C) 2014 Sebastian 'tokkee' Harl <sh@tokkee.org>
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions
+// are met:
+// 1. Redistributions of source code must retain the above copyright
+//    notice, this list of conditions and the following disclaimer.
+// 2. Redistributions in binary form must reproduce the above copyright
+//    notice, this list of conditions and the following disclaimer in the
+//    documentation and/or other materials provided with the distribution.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+// TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+// PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR
+// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+// EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
+// OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+// WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
+// OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+// ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+package server
+
+// Helper functions for handling and plotting graphs.
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"strings"
+	"time"
+
+	"code.google.com/p/plotinum/plot"
+	"code.google.com/p/plotinum/plotter"
+	"code.google.com/p/plotinum/plotutil"
+	"code.google.com/p/plotinum/vg"
+	"code.google.com/p/plotinum/vg/vgsvg"
+	"github.com/sysdb/go/proto"
+	"github.com/sysdb/go/sysdb"
+)
+
+func (s *Server) graph(w http.ResponseWriter, req request) {
+	if len(req.args) < 2 {
+		s.internal(w, fmt.Errorf("Missing host/metric information"))
+	}
+
+	host := proto.EscapeString(req.args[0])
+	metric := proto.EscapeString(strings.Join(req.args[1:], "/"))
+	res, err := s.query(fmt.Sprintf("TIMESERIES %s.%s", host, metric))
+	if err != nil {
+		s.internal(w, fmt.Errorf("Failed to retrieve graph data: %v", err))
+		return
+	}
+
+	ts, ok := res.(sysdb.Timeseries)
+	if !ok {
+		s.internal(w, errors.New("TIMESERIES did not return a time-series"))
+		return
+	}
+
+	p, err := plot.New()
+	if err != nil {
+		s.internal(w, fmt.Errorf("Failed to create plot: %v", err))
+		return
+	}
+	p.Add(plotter.NewGrid())
+
+	var i int
+	for name, data := range ts.Data {
+		pts := make(plotter.XYs, len(data))
+		for i, p := range data {
+			pts[i].X = float64(time.Time(p.Timestamp).UnixNano())
+			pts[i].Y = p.Value
+		}
+		l, err := plotter.NewLine(pts)
+		if err != nil {
+			s.internal(w, fmt.Errorf("Failed to create line plotter: %v", err))
+			return
+		}
+		l.LineStyle.Color = plotutil.DarkColors[i%len(plotutil.DarkColors)]
+		p.Add(l)
+		p.Legend.Add(name, l)
+		i++
+	}
+
+	c := vgsvg.New(vg.Length(500), vg.Length(200))
+	p.Draw(plot.MakeDrawArea(c))
+
+	var buf bytes.Buffer
+	if _, err := c.WriteTo(&buf); err != nil {
+		s.internal(w, fmt.Errorf("Failed to write plot: %v", err))
+		return
+	}
+	w.Header().Set("Content-Type", "image/svg+xml")
+	w.WriteHeader(http.StatusOK)
+	io.Copy(w, &buf)
+}
+
+// vim: set tw=78 sw=4 sw=4 noexpandtab :
diff --git a/server/server.go b/server/server.go
index 33a2536..59c1e42 100644
--- a/server/server.go
+++ b/server/server.go
@@ -104,6 +104,7 @@ func New(cfg Config) (*Server, error) {
 	s.mux = map[string]handler{
 		"images": s.static,
 		"style":  s.static,
+		"graph":  s.graph,
 	}
 	return s, nil
 }
@@ -317,6 +318,10 @@ func (s *Server) query(cmd string) (interface{}, error) {
 			var host sysdb.Host
 			err = proto.Unmarshal(m, &host)
 			res = host
+		case proto.Timeseries:
+			var ts sysdb.Timeseries
+			err = proto.Unmarshal(m, &ts)
+			res = ts
 		default:
 			return nil, fmt.Errorf("Unsupported data type %d", t)
 		}
diff --git a/templates/metric.tmpl b/templates/metric.tmpl
index e4a0efb..a264801 100644
--- a/templates/metric.tmpl
+++ b/templates/metric.tmpl
@@ -1,5 +1,6 @@
 <section>{{$m := index .Metrics 0}}
 	<h1>Metric {{$.Name}} &mdash; {{$m.Name}}</h1>
+	<img src="/graph/{{urlquery $.Name}}/{{urlquery $m.Name}}" border="0" />
 	<table class="results">
 		<tr><td><b>Host</b></td><td><a href="/host/{{urlquery $.Name}}">{{$.Name}}</a></td></tr>
 		<tr><td><b>Last update</b></td><td>{{$m.LastUpdate}}</td></tr>