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// Simple wrapper for rrdtool C library
package rrd
import (
"fmt"
"math"
"os"
"strings"
"time"
"unsafe"
)
type Error string
func (e Error) Error() string {
return string(e)
}
type cstring []byte
func newCstring(s string) cstring {
cs := make(cstring, len(s)+1)
copy(cs, s)
return cs
}
func (cs cstring) p() unsafe.Pointer {
if len(cs) == 0 {
return nil
}
return unsafe.Pointer(&cs[0])
}
func (cs cstring) String() string {
return string(cs[:len(cs)-1])
}
func join(args []interface{}) string {
sa := make([]string, len(args))
for i, a := range args {
var s string
switch v := a.(type) {
case time.Time:
s = i64toa(v.Unix())
default:
s = fmt.Sprint(v)
}
sa[i] = s
}
return strings.Join(sa, ":")
}
type Creator struct {
filename string
start time.Time
step uint
args []string
}
// NewCreator returns new Creator object. You need to call Create to really
// create database file.
// filename - name of database file
// start - don't accept any data timed before or at time specified
// step - base interval in seconds with which data will be fed into RRD
func NewCreator(filename string, start time.Time, step uint) *Creator {
return &Creator{
filename: filename,
start: start,
step: step,
}
}
func (c *Creator) DS(name, compute string, args ...interface{}) {
c.args = append(c.args, "DS:"+name+":"+compute+":"+join(args))
}
func (c *Creator) RRA(cf string, args ...interface{}) {
c.args = append(c.args, "RRA:"+cf+":"+join(args))
}
// Create creates new database file. If overwrite is true it overwrites
// database file if exists. If overwrite is false it returns error if file
// exists (you can use os.IsExist function to check this case).
func (c *Creator) Create(overwrite bool) error {
if !overwrite {
f, err := os.OpenFile(
c.filename,
os.O_WRONLY|os.O_CREATE|os.O_EXCL,
0666,
)
if err != nil {
return err
}
f.Close()
}
return c.create()
}
// Use cstring and unsafe.Pointer to avoid alocations for C calls
type Updater struct {
filename cstring
template cstring
args []unsafe.Pointer
}
func NewUpdater(filename string) *Updater {
return &Updater{filename: newCstring(filename)}
}
func (u *Updater) SetTemplate(dsName ...string) {
u.template = newCstring(strings.Join(dsName, ":"))
}
// Cache chaches data for later save using Update(). Use it to avoid
// open/read/write/close for every update.
func (u *Updater) Cache(args ...interface{}) {
u.args = append(u.args, newCstring(join(args)).p())
}
// Update saves data in RRDB.
// Without args Update saves all subsequent updates buffered by Cache method.
// If you specify args it saves them immediately.
func (u *Updater) Update(args ...interface{}) error {
if len(args) != 0 {
a := make([]unsafe.Pointer, 1)
a[0] = newCstring(join(args)).p()
return u.update(a)
} else if len(u.args) != 0 {
err := u.update(u.args)
u.args = nil
return err
}
return nil
}
type GraphInfo struct {
Print []string
Width, Height uint
Ymin, Ymax float64
}
type Grapher struct {
title string
vlabel string
width, height uint
upperLimit float64
lowerLimit float64
rigid bool
altAutoscale bool
altAutoscaleMin bool
altAutoscaleMax bool
noGridFit bool
logarithmic bool
unitsExponent int
unitsLength uint
rightAxisScale float64
rightAxisShift float64
rightAxisLabel string
noLegend bool
lazy bool
color string
slopeMode bool
watermark string
base uint
imageFormat string
interlaced bool
args []string
}
const (
maxUint = ^uint(0)
maxInt = int(maxUint >> 1)
minInt = -maxInt - 1
)
func NewGrapher() *Grapher {
return &Grapher{
upperLimit: -math.MaxFloat64,
lowerLimit: math.MaxFloat64,
unitsExponent: minInt,
}
}
func (g *Grapher) SetTitle(title string) {
g.title = title
}
func (g *Grapher) SetVLabel(vlabel string) {
g.vlabel = vlabel
}
func (g *Grapher) SetSize(width, height uint) {
g.width = width
g.height = height
}
func (g *Grapher) SetLowerLimit(limit float64) {
g.lowerLimit = limit
}
func (g *Grapher) SetUpperLimit(limit float64) {
g.upperLimit = limit
}
func (g *Grapher) SetRigid() {
g.rigid = true
}
func (g *Grapher) SetAltAutoscale() {
g.altAutoscale = true
}
func (g *Grapher) SetAltAutoscaleMin() {
g.altAutoscaleMin = true
}
func (g *Grapher) SetAltAutoscaleMax() {
g.altAutoscaleMax = true
}
func (g *Grapher) SetNoGridFit() {
g.noGridFit = true
}
func (g *Grapher) SetLogarithmic() {
g.logarithmic = true
}
func (g *Grapher) SetUnitsExponent(e int) {
g.unitsExponent = e
}
func (g *Grapher) SetUnitsLength(l uint) {
g.unitsLength = l
}
func (g *Grapher) SetRightAxis(scale, shift float64) {
g.rightAxisScale = scale
g.rightAxisShift = shift
}
func (g *Grapher) SetRightAxisLabel(label string) {
g.rightAxisLabel = label
}
func (g *Grapher) SetNoLegend() {
g.noLegend = true
}
func (g *Grapher) SetLazy() {
g.lazy = true
}
func (g *Grapher) SetColor(colortag, color string) {
g.color = colortag + "#" + color
}
func (g *Grapher) SetSlopeMode() {
g.slopeMode = true
}
func (g *Grapher) SetImageFormat(format string) {
g.imageFormat = format
}
func (g *Grapher) SetInterlaced() {
g.interlaced = true
}
func (g *Grapher) SetBase(base uint) {
g.base = base
}
func (g *Grapher) SetWatermark(watermark string) {
g.watermark = watermark
}
func (g *Grapher) push(cmd string, options []string) {
if len(options) > 0 {
cmd += ":" + strings.Join(options, ":")
}
g.args = append(g.args, cmd)
}
func (g *Grapher) Def(vname, rrdfile, dsname, cf string, options ...string) {
g.push(
fmt.Sprintf("DEF:%s=%s:%s:%s", vname, rrdfile, dsname, cf),
options,
)
}
func (g *Grapher) VDef(vname, rpn string) {
g.push("VDEF:"+vname+"="+rpn, nil)
}
func (g *Grapher) CDef(vname, rpn string) {
g.push("CDEF:"+vname+"="+rpn, nil)
}
func (g *Grapher) Print(vname, format string) {
g.push("PRINT:"+vname+":"+format, nil)
}
func (g *Grapher) PrintT(vname, format string) {
g.push("PRINT:"+vname+":"+format+":strftime", nil)
}
func (g *Grapher) GPrint(vname, format string) {
g.push("GPRINT:"+vname+":"+format, nil)
}
func (g *Grapher) GPrintT(vname, format string) {
g.push("GPRINT:"+vname+":"+format+":strftime", nil)
}
func (g *Grapher) Comment(s string) {
g.push("COMMENT:"+s, nil)
}
func (g *Grapher) VRule(t interface{}, color string, options ...string) {
if v, ok := t.(time.Time); ok {
t = v.Unix()
}
vr := fmt.Sprintf("VRULE:%s#%s", t, color)
g.push(vr, options)
}
func (g *Grapher) HRule(value, color string, options ...string) {
hr := "HRULE:" + value + "#" + color
g.push(hr, options)
}
func (g *Grapher) Line(width float32, value, color string, options ...string) {
line := fmt.Sprintf("LINE%f:%s", width, value)
if color != "" {
line += "#" + color
}
g.push(line, options)
}
func (g *Grapher) Area(value, color string, options ...string) {
area := "AREA:" + value
if color != "" {
area += "#" + color
}
g.push(area, options)
}
func (g *Grapher) Tick(vname, color string, options ...string) {
tick := "TICK:" + vname
if color != "" {
tick += "#" + color
}
g.push(tick, options)
}
func (g *Grapher) Shift(vname string, offset interface{}) {
if v, ok := offset.(time.Duration); ok {
offset = int64((v + time.Second/2) / time.Second)
}
shift := fmt.Sprintf("SHIFT:%s:%s", offset)
g.push(shift, nil)
}
func (g *Grapher) TextAlign(align string) {
g.push("TEXTALIGN:"+align, nil)
}
// Graph returns GraphInfo and image as []byte or error
func (g *Grapher) Graph(start, end time.Time) (GraphInfo, []byte, error) {
return g.graph("-", start, end)
}
// SaveGraph saves image to file and returns GraphInfo or error
func (g *Grapher) SaveGraph(filename string, start, end time.Time) (GraphInfo, error) {
gi, _, err := g.graph(filename, start, end)
return gi, err
}
type FetchResult struct {
Filename string
Cf string
Start time.Time
End time.Time
Step time.Duration
DsNames []string
RowCnt int
values []float64
}
func (r *FetchResult) ValueAt(dsIndex, rowIndex int) float64 {
return r.values[len(r.DsNames)*rowIndex+dsIndex]
}
type Exporter struct {
maxRows uint
args []string
}
func NewExporter() *Exporter {
return &Exporter{}
}
func (e *Exporter) SetMaxRows(maxRows uint) {
e.maxRows = maxRows
}
func (e *Exporter) push(cmd string, options []string) {
if len(options) > 0 {
cmd += ":" + strings.Join(options, ":")
}
e.args = append(e.args, cmd)
}
func (e *Exporter) Def(vname, rrdfile, dsname, cf string, options ...string) {
e.push(
fmt.Sprintf("DEF:%s=%s:%s:%s", vname, rrdfile, dsname, cf),
options,
)
}
func (e *Exporter) CDef(vname, rpn string) {
e.push("CDEF:"+vname+"="+rpn, nil)
}
func (e *Exporter) XportDef(vname, label string) {
e.push("XPORT:"+vname+":"+label, nil)
}
func (e *Exporter) Xport(start, end time.Time, step time.Duration) (XportResult, error) {
return e.xport(start, end, step)
}
type XportResult struct {
Start time.Time
End time.Time
Step time.Duration
Legends []string
RowCnt int
values []float64
}
func (r *XportResult) ValueAt(legendIndex, rowIndex int) float64 {
return r.values[len(r.Legends)*rowIndex+legendIndex]
}
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