135 lines
3.7 KiB
Go
135 lines
3.7 KiB
Go
package downloader
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import (
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"context"
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"emperror.dev/errors"
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"github.com/google/uuid"
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"github.com/pterodactyl/wings/server"
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"net/http"
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"net/url"
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"path/filepath"
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"strings"
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"sync"
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"time"
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)
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type Downloader struct {
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mu sync.RWMutex
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downloadCache map[string]Download
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serverCache map[string][]string
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}
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type DownloadRequest struct {
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URL *url.URL
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Directory string
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}
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type Download struct {
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Identifier string
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req DownloadRequest
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server *server.Server
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cancelFunc *context.CancelFunc
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}
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var client = &http.Client{Timeout: time.Hour * 12}
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var instance = &Downloader{
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// Tracks all of the active downloads.
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downloadCache: make(map[string]Download),
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// Tracks all of the downloads active for a given server instance. This is
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// primarily used to make things quicker and keep the code a little more
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// legible throughout here.
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serverCache: make(map[string][]string),
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}
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// Starts a new tracked download which allows for cancelation later on by calling
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// the Downloader.Cancel function.
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func New(s *server.Server, r DownloadRequest) *Download {
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dl := Download{
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Identifier: uuid.Must(uuid.NewRandom()).String(),
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req: r,
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server: s,
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}
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instance.track(dl)
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return &dl
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}
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// Executes a given download for the server and begins writing the file to the disk. Once
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// completed the download will be removed from the cache.
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func (dl *Download) Execute() error {
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ctx, cancel := context.WithTimeout(context.Background(), time.Hour*12)
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dl.cancelFunc = &cancel
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defer dl.Cancel()
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req, _ := http.NewRequestWithContext(ctx, http.MethodGet, dl.req.URL.String(), nil)
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res, err := client.Do(req)
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if err != nil {
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return errors.New("downloader: failed opening request to download file")
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}
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defer res.Body.Close()
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if res.StatusCode >= 300 || res.StatusCode < 200 {
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return errors.New("downloader: got bad response status from endpoint: " + res.Status)
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}
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fnameparts := strings.Split(dl.req.URL.Path, "/")
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p := filepath.Join(dl.req.Directory, fnameparts[len(fnameparts)-1])
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dl.server.Log().WithField("path", p).Debug("writing remote file to disk")
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if err := dl.server.Filesystem().Writefile(p, res.Body); err != nil {
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return errors.WrapIf(err, "downloader: failed to write file to server directory")
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}
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return nil
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}
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// Cancels a running download and frees up the associated resources. If a file is being
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// written a partial file will remain present on the disk.
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func (dl *Download) Cancel() {
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if dl.cancelFunc != nil {
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(*dl.cancelFunc)()
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}
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instance.remove(dl.Identifier)
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}
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// Tracks a download in the internal cache for this instance.
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func (d *Downloader) track(dl Download) {
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d.mu.Lock()
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defer d.mu.Unlock()
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sid := dl.server.Id()
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if _, ok := d.downloadCache[dl.Identifier]; !ok {
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d.downloadCache[dl.Identifier] = dl
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if _, ok := d.serverCache[sid]; !ok {
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d.serverCache[sid] = []string{}
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}
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d.serverCache[sid] = append(d.serverCache[sid], dl.Identifier)
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}
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}
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// Finds a given download entry using the provided ID and returns it.
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func (d *Downloader) find(dlid string) (Download, bool) {
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d.mu.RLock()
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defer d.mu.RUnlock()
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if entry, ok := d.downloadCache[dlid]; ok {
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return entry, true
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}
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return Download{}, false
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}
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// Remove the given download reference from the cache storing them. This also updates
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// the slice of active downloads for a given server to not include this download.
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func (d *Downloader) remove(dlid string) {
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d.mu.Lock()
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defer d.mu.Unlock()
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if _, ok := d.downloadCache[dlid]; !ok {
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return
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}
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sid := d.downloadCache[dlid].server.Id()
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delete(d.downloadCache, dlid)
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if tracked, ok := d.serverCache[sid]; ok {
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var out []string
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for _, k := range tracked {
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if k != dlid {
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out = append(out, k)
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}
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}
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d.serverCache[sid] = out
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}
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}
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