querylogz.go

// Copyright 2012, Google Inc. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package tabletserver

import (
	"fmt"
	"net/http"
	"strconv"
	"strings"
	"text/template"
	"time"
)

var (
	querylogzHeader = []byte(`
		<tr>
			<th>Method</th>
			<th>Client</th>
			<th>User</th>
			<th>Start</th>
			<th>End</th>
			<th>Duration</th>
			<th>MySQL time</th>
			<th>Conn wait</th>
			<th>Plan</th>
			<th>SQL</th>
			<th>Queries</th>
			<th>Sources</th>
			<th>Rows</th>
			<th>Hits</th>
			<th>Misses</th>
			<th>Absent</th>
			<th>Invalidations</th>
		</tr>
	`)
	querylogzTmpl = template.Must(template.New("example").Parse(`
		<tr class="{{.Color}}">
			<td>{{.Method}}</td>
			<td>{{.RemoteAddr}}</td>
			<td>{{.Username}}</td>
			<td>{{.Start}}</td>
			<td>{{.End}}</td>
			<td>{{.Duration}}</td>
			<td>{{.MySQL}}</td>
			<td>{{.Conn}}</td>
			<td>{{.PlanType}}</td>
			<td>{{.Sql}}</td>
			<td>{{.Queries}}</td>
			<td>{{.Sources}}</td>
			<td>{{.Rows}}</td>
			<td>{{.Hits}}</td>
			<td>{{.Misses}}</td>
			<td>{{.Absent}}</td>
			<td>{{.Invalidations}}</td>
		</tr>
	`))
)

type querylogzRow struct {
	Method        string
	RemoteAddr    string
	Username      string
	Start         string
	End           string
	Duration      string
	MySQL         string
	Conn          string
	PlanType      string
	Sql           string
	Queries       string
	Sources       string
	Rows          string
	Hits          string
	Misses        string
	Absent        string
	Invalidations string
	Color         string
}

func init() {
	http.HandleFunc("/querylogz", querylogzHandler)
}

// querylogzHandler serves a human readable snapshot of the
// current query log.
func querylogzHandler(w http.ResponseWriter, r *http.Request) {
	ch := SqlQueryLogger.Subscribe(nil)
	defer SqlQueryLogger.Unsubscribe(ch)
	startHTMLTable(w)
	defer endHTMLTable(w)
	w.Write(querylogzHeader)

	deadline := time.After(10 * time.Second)
	for i := 0; i < 300; i++ {
		select {
		case out := <-ch:
			strs := strings.Split(strings.Trim(out, "\n"), "\t")
			if len(strs) < 19 {
				querylogzTmpl.Execute(w, &querylogzRow{Method: fmt.Sprintf("Short: %d", len(strs))})
				continue
			}
			Value := &querylogzRow{
				Method:        strs[0],
				RemoteAddr:    strs[1],
				Username:      strs[2],
				Start:         strs[3],
				End:           strs[4],
				Duration:      strs[5],
				MySQL:         strs[12],
				Conn:          strs[13],
				PlanType:      strs[6],
				Sql:           strings.Trim(strs[7], "\""),
				Queries:       strs[9],
				Sources:       strs[11],
				Rows:          strs[14],
				Hits:          strs[15],
				Misses:        strs[16],
				Absent:        strs[17],
				Invalidations: strs[18],
			}
			duration, _ := strconv.ParseFloat(Value.Duration, 64)
			if duration < 0.01 {
				Value.Color = "low"
			} else if duration < 0.1 {
				Value.Color = "medium"
			} else {
				Value.Color = "high"
			}
			querylogzTmpl.Execute(w, Value)
		case <-deadline:
			return
		}
	}
}