118 lines
2.1 KiB
Go
118 lines
2.1 KiB
Go
package oci
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import (
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"context"
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"fmt"
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"os"
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"path/filepath"
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"github.com/containers/image/v5/types"
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)
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const (
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defaultCachePath = "/var/warewulf/vnfs-cache/oci/"
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blobPrefix = "blobs"
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rootfsPrefix = "rootfs"
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)
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type CacheOpt func(*Cache) error
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func OptSetCachePath(path string) CacheOpt {
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return func(s *Cache) error {
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s.path = path
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return nil
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}
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}
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type Cache struct {
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path string
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}
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func (c *Cache) rootfsDir() string {
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return filepath.Join(c.path, rootfsPrefix)
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}
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func (c *Cache) blobDir() string {
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return filepath.Join(c.path, blobPrefix)
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}
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// checkEntry maps the given id a path within the cache. It will return an os.ErrNotExist if the entry path is empty.
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func (c *Cache) checkEntry(id string) (string, error) {
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path := filepath.Join(c.rootfsDir(), id)
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fi, err := os.Stat(path)
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if err != nil {
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return "", err
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}
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if !fi.IsDir() {
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return "", fmt.Errorf("invalid entry %q is not a directory", path)
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}
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return path, nil
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}
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func (c *Cache) createEntry(id string) (string, error) {
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path := filepath.Join(c.rootfsDir(), id)
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if err := os.MkdirAll(path, 755); err != nil {
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return "", err
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}
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return path, nil
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}
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func NewCache(opts ...CacheOpt) (*Cache, error) {
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s := &Cache{
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path: filepath.Join(defaultCachePath),
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}
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for _, o := range opts {
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if err := o(s); err != nil {
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return nil, err
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}
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}
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if err := os.MkdirAll(s.path, 0755); err != nil {
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return nil, err
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}
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return s, nil
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}
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func (c *Cache) Pull(ctx context.Context, uri string, sysCtx *types.SystemContext) (string, error) {
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p, err := NewPuller(
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OptSetBlobCachePath(c.blobDir()),
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OptSetSystemContext(sysCtx),
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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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id, err := p.GenerateID(ctx, uri)
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if err != nil {
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return "", err
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}
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// look up cache entry and return if it exists
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path, err := c.checkEntry(id)
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if err == nil {
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return path, nil
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} else if !os.IsNotExist(err) {
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return "", err
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}
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// cache entry does not exist so we must create it
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path, err = c.createEntry(id)
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if err != nil {
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return "", err
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}
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// populate entry
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if err := p.Pull(ctx, uri, path); err != nil {
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// clean up entry on error
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os.RemoveAll(path)
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return "", err
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}
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return path, nil
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}
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