79 lines
1.6 KiB
Go
79 lines
1.6 KiB
Go
package cache
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import (
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"errors"
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"log/slog"
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"os"
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"path/filepath"
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)
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func (c *Cache) Fetch(relPath string) (*CacheFile, error) {
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// return file directly if exists in cache
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cf, err := getCachedFile(c.cfg.cacheRoot, relPath)
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if err == nil {
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return cf, nil
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}
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// fetch file from upstream
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_, err, _ = c.sf.Do(relPath, func() (any, error) {
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slog.Info("calling fetch")
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return nil, c.fetch(relPath)
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})
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if err != nil {
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return nil, err
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}
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cf, err = getCachedFile(c.cfg.cacheRoot, relPath)
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if err != nil {
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return nil, err
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}
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return cf, nil
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}
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func (c *Cache) fetch(relPath string) error {
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// relPath is relative to the localRoot
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// ie relPath includes /{repo}/os/{arch}/ and the actual name linux-x.x.x.pkg.tar.zst
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// final file name and path
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destPath := filepath.Join(c.cfg.cacheRoot, relPath)
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// declare vars outside loop
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var err error
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// fetch pkgs from mirror with retry logic
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for range len(c.cfg.mirrorURLs) {
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url := c.nextMirror() + relPath
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err = downloadToDisk(url, destPath, c.client)
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if err == nil {
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break
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}
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if upstreamErr, ok := errors.AsType[*UpstreamError](err); ok {
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slog.Warn("mirror failed", "url", url, "status", upstreamErr.StatusCode)
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} else {
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slog.Warn("mirror unreachable", "url", url, "err", err)
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}
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}
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if err != nil {
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return err
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}
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return nil
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}
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func getCachedFile(cacheRoot, relPath string) (*CacheFile, error) {
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filePath := filepath.Join(cacheRoot, relPath)
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info, err := os.Stat(filePath)
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if err != nil {
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return nil, err
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}
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f, err := os.Open(filePath)
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if err != nil {
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return nil, err
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}
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return &CacheFile{
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Reader: f,
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Size: info.Size(),
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Filename: filepath.Base(filePath),
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}, nil
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}
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