1 files changed, 123 insertions, 0 deletions
diff --git a/workhorse/internal/artifacts/entry.go b/workhorse/internal/artifacts/entry.go
new file mode 100644
index 00000000000..0c697d40020
--- /dev/null
+++ b/workhorse/internal/artifacts/entry.go
@@ -0,0 +1,123 @@
+package artifacts
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"io"
+	"mime"
+	"net/http"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"syscall"
+
+	"gitlab.com/gitlab-org/labkit/log"
+
+	"gitlab.com/gitlab-org/gitlab-workhorse/internal/helper"
+	"gitlab.com/gitlab-org/gitlab-workhorse/internal/senddata"
+	"gitlab.com/gitlab-org/gitlab-workhorse/internal/zipartifacts"
+)
+
+type entry struct{ senddata.Prefix }
+type entryParams struct{ Archive, Entry string }
+
+var SendEntry = &entry{"artifacts-entry:"}
+
+// Artifacts downloader doesn't support ranges when downloading a single file
+func (e *entry) Inject(w http.ResponseWriter, r *http.Request, sendData string) {
+	var params entryParams
+	if err := e.Unpack(&params, sendData); err != nil {
+		helper.Fail500(w, r, fmt.Errorf("SendEntry: unpack sendData: %v", err))
+		return
+	}
+
+	log.WithContextFields(r.Context(), log.Fields{
+		"entry":   params.Entry,
+		"archive": params.Archive,
+		"path":    r.URL.Path,
+	}).Print("SendEntry: sending")
+
+	if params.Archive == "" || params.Entry == "" {
+		helper.Fail500(w, r, fmt.Errorf("SendEntry: Archive or Entry is empty"))
+		return
+	}
+
+	err := unpackFileFromZip(r.Context(), params.Archive, params.Entry, w.Header(), w)
+
+	if os.IsNotExist(err) {
+		http.NotFound(w, r)
+	} else if err != nil {
+		helper.Fail500(w, r, fmt.Errorf("SendEntry: %v", err))
+	}
+}
+
+func detectFileContentType(fileName string) string {
+	contentType := mime.TypeByExtension(filepath.Ext(fileName))
+	if contentType == "" {
+		contentType = "application/octet-stream"
+	}
+	return contentType
+}
+
+func unpackFileFromZip(ctx context.Context, archivePath, encodedFilename string, headers http.Header, output io.Writer) error {
+	fileName, err := zipartifacts.DecodeFileEntry(encodedFilename)
+	if err != nil {
+		return err
+	}
+
+	catFile := exec.Command("gitlab-zip-cat")
+	catFile.Env = append(os.Environ(),
+		"ARCHIVE_PATH="+archivePath,
+		"ENCODED_FILE_NAME="+encodedFilename,
+	)
+	catFile.Stderr = log.ContextLogger(ctx).Writer()
+	catFile.SysProcAttr = &syscall.SysProcAttr{Setpgid: true}
+	stdout, err := catFile.StdoutPipe()
+	if err != nil {
+		return fmt.Errorf("create gitlab-zip-cat stdout pipe: %v", err)
+	}
+
+	if err := catFile.Start(); err != nil {
+		return fmt.Errorf("start %v: %v", catFile.Args, err)
+	}
+	defer helper.CleanUpProcessGroup(catFile)
+
+	basename := filepath.Base(fileName)
+	reader := bufio.NewReader(stdout)
+	contentLength, err := reader.ReadString('\n')
+	if err != nil {
+		if catFileErr := waitCatFile(catFile); catFileErr != nil {
+			return catFileErr
+		}
+		return fmt.Errorf("read content-length: %v", err)
+	}
+	contentLength = strings.TrimSuffix(contentLength, "\n")
+
+	// Write http headers about the file
+	headers.Set("Content-Length", contentLength)
+	headers.Set("Content-Type", detectFileContentType(fileName))
+	headers.Set("Content-Disposition", "attachment; filename=\""+escapeQuotes(basename)+"\"")
+	// Copy file body to client
+	if _, err := io.Copy(output, reader); err != nil {
+		return fmt.Errorf("copy stdout of %v: %v", catFile.Args, err)
+	}
+
+	return waitCatFile(catFile)
+}
+
+func waitCatFile(cmd *exec.Cmd) error {
+	err := cmd.Wait()
+	if err == nil {
+		return nil
+	}
+
+	st, ok := helper.ExitStatus(err)
+
+	if ok && (st == zipartifacts.CodeArchiveNotFound || st == zipartifacts.CodeEntryNotFound) {
+		return os.ErrNotExist
+	}
+	return fmt.Errorf("wait for %v to finish: %v", cmd.Args, err)
+
+}