60 lines
1.4 KiB
Go
60 lines
1.4 KiB
Go
//go:build windows
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package metrics
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import (
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"context"
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"errors"
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"fmt"
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"time"
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"golang.org/x/sys/windows"
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)
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const diskQueryTimeout = 2 * time.Second
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// getDiskFreeSpaceEx is a package-level seam so tests can substitute a fake.
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var getDiskFreeSpaceEx = windows.GetDiskFreeSpaceEx
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type diskQueryResult struct {
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totalBytes uint64
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freeBytes uint64
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err error
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}
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func diskPercent(ctx context.Context, path string) (float64, error) {
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dir, err := windows.UTF16PtrFromString(path)
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if err != nil {
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return 0, fmt.Errorf("convert path %q: %w", path, err)
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}
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result := make(chan diskQueryResult, 1)
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go func() {
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var freeToCaller, totalBytes, totalFree uint64
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callErr := getDiskFreeSpaceEx(dir, &freeToCaller, &totalBytes, &totalFree)
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result <- diskQueryResult{totalBytes: totalBytes, freeBytes: totalFree, err: callErr}
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}()
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timer := time.NewTimer(diskQueryTimeout)
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defer timer.Stop()
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select {
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case <-ctx.Done():
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return 0, ctx.Err()
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case <-timer.C:
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return 0, fmt.Errorf("disk usage timed out for %q", path)
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case res := <-result:
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if res.err != nil {
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return 0, fmt.Errorf("GetDiskFreeSpaceEx %q: %w", path, res.err)
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}
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return diskPercentFromBytes(res.totalBytes, res.freeBytes)
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}
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}
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func diskPercentFromBytes(total, free uint64) (float64, error) {
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if total == 0 {
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return 0, errors.New("disk total is zero")
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}
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return (1 - float64(free)/float64(total)) * 100, nil
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}
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