95 lines
1.9 KiB
Go
95 lines
1.9 KiB
Go
package cache
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import (
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"fmt"
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"io"
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"net"
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"net/http"
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"os"
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"path/filepath"
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"sync"
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"time"
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"golang.org/x/sync/singleflight"
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)
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type Cache struct {
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cacheRoot string
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mirrorURL string
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mirroredRepos []string
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sf singleflight.Group //prevents duplicate downloads
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mu sync.Mutex
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client http.Client
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}
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func NewCache(cacheRoot string, mirrorURL string) *Cache {
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transport := &http.Transport{
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DialContext: (&net.Dialer{
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Timeout: 5 * time.Second,
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}).DialContext,
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ResponseHeaderTimeout: 10 * time.Second,
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}
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return &Cache{
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cacheRoot: cacheRoot,
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mirrorURL: mirrorURL,
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mirroredRepos: []string{"core", "extra", "multilib"},
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client: http.Client{
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Timeout: 15 * time.Second,
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Transport: transport,
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},
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}
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}
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func (c *Cache) Fetch(pkgPath string) error {
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_, err, _ := c.sf.Do(pkgPath, func() (any, error) {
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return nil, c.fetch(pkgPath)
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})
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return err
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}
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type UpstreamError struct {
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StatusCode int
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}
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func (e *UpstreamError) Error() string {
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return fmt.Sprintf("upstream returned %d", e.StatusCode)
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}
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func (c *Cache) fetch(pkgName string) error {
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// pkgName is relative to the localRoot
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// ie pkgName includes /{repo}/os/{arch}/ and the actual name linux-x.x.x.pkg.tar.zst
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tempPkgName := pkgName + ".tmp"
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tempPkgPath := filepath.Join(c.cacheRoot, tempPkgName) //full tmp write path
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outPkg := filepath.Join(c.cacheRoot, pkgName)
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pkgURL := c.mirrorURL + pkgName
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resp, err := c.client.Get(pkgURL)
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if err != nil {
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return err
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}
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defer resp.Body.Close()
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if resp.StatusCode != http.StatusOK {
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return &UpstreamError{StatusCode: resp.StatusCode}
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}
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outFile, err := os.Create(tempPkgPath)
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if err != nil {
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return err
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}
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defer outFile.Close()
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_, err = io.Copy(outFile, resp.Body)
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if err != nil {
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os.Remove(tempPkgPath)
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return err
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}
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if err := os.Rename(tempPkgPath, outPkg); err != nil {
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os.Remove(tempPkgPath)
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return err
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}
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return nil
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}
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