mirror of
https://github.com/seaweedfs/seaweedfs.git
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Chris Lu
737cc0f330
Introduce a small Loader interface so the service can stay oblivious to the storage backend behind a Parquet path: tests inject a LocalLoader backed by os.File, and the daemon will plug in a filer-backed Loader in a later milestone. FileHandle is the parser-friendly view: io.ReaderAt + io.Closer + Size(). LocalLoader rejects missing files and directories up front so service-level error paths see a clear "open failed" rather than a later ReadAt EOF. The Service does not yet consume Loader — that wiring lands in M1-C4 along with the predicate-less Pushdown handler that actually issues loads.
58 lines
1.6 KiB
Go
58 lines
1.6 KiB
Go
package parquet_pushdown
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import (
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"context"
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"fmt"
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"io"
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"os"
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)
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// FileHandle is what the service hands to the parser: a positional
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// reader bound to a known size, with a Close so the caller can
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// release any underlying resources.
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type FileHandle interface {
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io.ReaderAt
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io.Closer
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Size() int64
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}
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// Loader resolves a Parquet file's path to a FileHandle. The split
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// between "local file" and "filer-backed" implementations lives here
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// so the service stays oblivious to the storage backend, and so
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// integration tests can plug in deterministic local files instead of
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// spinning up a filer.
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type Loader interface {
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Open(ctx context.Context, path string) (FileHandle, error)
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}
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// LocalLoader treats `path` as a filesystem path. Used by integration
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// tests and for local-development smoke runs against a Parquet file
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// that is not under filer management.
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type LocalLoader struct{}
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func (LocalLoader) Open(_ context.Context, path string) (FileHandle, error) {
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f, err := os.Open(path)
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if err != nil {
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return nil, fmt.Errorf("open %q: %w", path, err)
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}
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st, err := f.Stat()
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if err != nil {
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_ = f.Close()
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return nil, fmt.Errorf("stat %q: %w", path, err)
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}
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if st.IsDir() {
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_ = f.Close()
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return nil, fmt.Errorf("%q is a directory", path)
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}
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return &localFile{f: f, size: st.Size()}, nil
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}
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type localFile struct {
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f *os.File
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size int64
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}
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func (l *localFile) ReadAt(p []byte, off int64) (int, error) { return l.f.ReadAt(p, off) }
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func (l *localFile) Close() error { return l.f.Close() }
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func (l *localFile) Size() int64 { return l.size }
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