1 files changed, 123 insertions, 0 deletions
diff --git a/workhorse/internal/dependencyproxy/dependencyproxy.go b/workhorse/internal/dependencyproxy/dependencyproxy.go
new file mode 100644
index 00000000000..cfb3045544f
--- /dev/null
+++ b/workhorse/internal/dependencyproxy/dependencyproxy.go
@@ -0,0 +1,123 @@
+package dependencyproxy
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"net"
+	"net/http"
+	"time"
+
+	"gitlab.com/gitlab-org/labkit/correlation"
+	"gitlab.com/gitlab-org/labkit/log"
+	"gitlab.com/gitlab-org/labkit/tracing"
+
+	"gitlab.com/gitlab-org/gitlab/workhorse/internal/helper"
+	"gitlab.com/gitlab-org/gitlab/workhorse/internal/senddata"
+)
+
+// httpTransport defines a http.Transport with values
+// that are more restrictive than for http.DefaultTransport,
+// they define shorter TLS Handshake, and more aggressive connection closing
+// to prevent the connection hanging and reduce FD usage
+var httpTransport = tracing.NewRoundTripper(correlation.NewInstrumentedRoundTripper(&http.Transport{
+	Proxy: http.ProxyFromEnvironment,
+	DialContext: (&net.Dialer{
+		Timeout:   30 * time.Second,
+		KeepAlive: 10 * time.Second,
+	}).DialContext,
+	MaxIdleConns:          2,
+	IdleConnTimeout:       30 * time.Second,
+	TLSHandshakeTimeout:   10 * time.Second,
+	ExpectContinueTimeout: 10 * time.Second,
+	ResponseHeaderTimeout: 30 * time.Second,
+}))
+
+var httpClient = &http.Client{
+	Transport: httpTransport,
+}
+
+type Injector struct {
+	senddata.Prefix
+	uploadHandler http.Handler
+}
+
+type entryParams struct {
+	Url    string
+	Header http.Header
+}
+
+type nullResponseWriter struct {
+	header http.Header
+	status int
+}
+
+func (nullResponseWriter) Write(p []byte) (int, error) {
+	return len(p), nil
+}
+
+func (w *nullResponseWriter) Header() http.Header {
+	return w.header
+}
+
+func (w *nullResponseWriter) WriteHeader(status int) {
+	if w.status == 0 {
+		w.status = status
+	}
+}
+
+func NewInjector() *Injector {
+	return &Injector{Prefix: "send-dependency:"}
+}
+
+func (p *Injector) SetUploadHandler(uploadHandler http.Handler) {
+	p.uploadHandler = uploadHandler
+}
+
+func (p *Injector) Inject(w http.ResponseWriter, r *http.Request, sendData string) {
+	dependencyResponse, err := p.fetchUrl(r.Context(), sendData)
+	if err != nil {
+		helper.Fail500(w, r, err)
+		return
+	}
+	defer dependencyResponse.Body.Close()
+	if dependencyResponse.StatusCode >= 400 {
+		w.WriteHeader(dependencyResponse.StatusCode)
+		io.Copy(w, dependencyResponse.Body)
+		return
+	}
+
+	teeReader := io.TeeReader(dependencyResponse.Body, w)
+	saveFileRequest, err := http.NewRequestWithContext(r.Context(), "POST", r.URL.String()+"/upload", teeReader)
+	if err != nil {
+		helper.Fail500(w, r, fmt.Errorf("dependency proxy: failed to create request: %w", err))
+	}
+	saveFileRequest.Header = helper.HeaderClone(r.Header)
+	saveFileRequest.ContentLength = dependencyResponse.ContentLength
+
+	w.Header().Del("Content-Length")
+
+	nrw := &nullResponseWriter{header: make(http.Header)}
+	p.uploadHandler.ServeHTTP(nrw, saveFileRequest)
+
+	if nrw.status != http.StatusOK {
+		fields := log.Fields{"code": nrw.status}
+
+		helper.Fail500WithFields(nrw, r, fmt.Errorf("dependency proxy: failed to upload file"), fields)
+	}
+}
+
+func (p *Injector) fetchUrl(ctx context.Context, sendData string) (*http.Response, error) {
+	var params entryParams
+	if err := p.Unpack(&params, sendData); err != nil {
+		return nil, fmt.Errorf("dependency proxy: unpack sendData: %v", err)
+	}
+
+	r, err := http.NewRequestWithContext(ctx, "GET", params.Url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("dependency proxy: failed to fetch dependency: %v", err)
+	}
+	r.Header = params.Header
+
+	return httpClient.Do(r)
+}