// Export data from RRD file(s)
func (e *Exporter) xport(start, end time.Time, step time.Duration) (XportResult, error) {
cStart := C.time_t(start.Unix())
cEnd := C.time_t(end.Unix())
cStep := C.ulong(step.Seconds())
args := e.makeArgs(start, end, step)
mutex.Lock()
defer mutex.Unlock()
var (
ret C.int
cXSize C.int
cColCnt C.ulong
cLegends **C.char
cData *C.double
)
err := makeError(C.rrdXport(
&ret,
C.int(len(args)),
&args[0],
&cXSize, &cStart, &cEnd, &cStep, &cColCnt, &cLegends, &cData,
))
if err != nil {
return XportResult{start, end, step, nil, 0, nil}, err
}
start = time.Unix(int64(cStart), 0)
end = time.Unix(int64(cEnd), 0)
step = time.Duration(cStep) * time.Second
colCnt := int(cColCnt)
legends := make([]string, colCnt)
for i := 0; i < colCnt; i++ {
legend := C.arrayGetCString(cLegends, C.int(i))
legends[i] = C.GoString(legend)
C.free(unsafe.Pointer(legend))
}
C.free(unsafe.Pointer(cLegends))
rowCnt := (int(cEnd)-int(cStart))/int(cStep) + 1
valuesLen := colCnt * rowCnt
values := make([]float64, valuesLen)
sliceHeader := (*reflect.SliceHeader)((unsafe.Pointer(&values)))
sliceHeader.Cap = valuesLen
sliceHeader.Len = valuesLen
sliceHeader.Data = uintptr(unsafe.Pointer(cData))
return XportResult{start, end, step, legends, rowCnt, values}, nil
}
// Fetch retrieves data from RRD file.
func Fetch(filename, cf string, start, end time.Time, step time.Duration) (FetchResult, error) {
var null **C.char
fn := C.CString(filename)
defer freeCString(fn)
cCf := C.CString(cf)
defer freeCString(cCf)
cStart := C.time_t(start.Unix())
cEnd := C.time_t(end.Unix())
cStep := C.ulong(step.Seconds())
var (
ret C.int
cDsCnt C.ulong
cDsNames **C.char
cData *C.double
)
err := makeError(C.rrdFetch(&ret, fn, cCf, &cStart, &cEnd, &cStep, &cDsCnt, &cDsNames, &cData))
if err != nil {
return FetchResult{filename, cf, start, end, step, nil, 0, nil}, err
}
if cDsNames == null {
return FetchResult{filename, cf, start, end, step, nil, 0, nil}, Error("malloc error")
}
start = time.Unix(int64(cStart), 0)
end = time.Unix(int64(cEnd), 0)
step = time.Duration(cStep) * time.Second
dsCnt := int(cDsCnt)
dsNames := make([]string, dsCnt)
for i := 0; i < dsCnt; i++ {
dsName := C.arrayGetCString(cDsNames, C.int(i))
dsNames[i] = C.GoString(dsName)
C.free(unsafe.Pointer(dsName))
}
C.free(unsafe.Pointer(cDsNames))
rowCnt := (int(cEnd)-int(cStart))/int(cStep) + 1
valuesLen := dsCnt * rowCnt
var values []float64
sliceHeader := (*reflect.SliceHeader)((unsafe.Pointer(&values)))
sliceHeader.Cap = valuesLen
sliceHeader.Len = valuesLen
sliceHeader.Data = uintptr(unsafe.Pointer(cData))
return FetchResult{filename, cf, start, end, step, dsNames, rowCnt, values}, nil
}