1 files changed, 38 insertions, 0 deletions
diff --git a/go/vendor/gitlab.com/gitlab-org/labkit/correlation/outbound_http.go b/go/vendor/gitlab.com/gitlab-org/labkit/correlation/outbound_http.go
new file mode 100644
index 0000000..0345a37
--- /dev/null
+++ b/go/vendor/gitlab.com/gitlab-org/labkit/correlation/outbound_http.go
@@ -0,0 +1,38 @@
+package correlation
+
+import (
+	"net/http"
+)
+
+const propagationHeader = "X-Request-ID"
+
+// injectRequest will pass the CorrelationId through to a downstream http request
+// for propagation
+func injectRequest(req *http.Request) {
+	correlationID := ExtractFromContext(req.Context())
+	if correlationID != "" {
+		req.Header.Set(propagationHeader, correlationID)
+	}
+}
+
+type instrumentedRoundTripper struct {
+	delegate http.RoundTripper
+}
+
+func (c instrumentedRoundTripper) RoundTrip(req *http.Request) (res *http.Response, e error) {
+	injectRequest(req)
+	return c.delegate.RoundTrip(req)
+}
+
+// NewInstrumentedRoundTripper acts as a "client-middleware" for outbound http requests
+// adding instrumentation to the outbound request and then delegating to the underlying
+// transport.
+//
+// If will extract the current Correlation-ID from the request context and pass this via
+// the X-Request-ID request header to downstream services.
+func NewInstrumentedRoundTripper(delegate http.RoundTripper, opts ...InstrumentedRoundTripperOption) http.RoundTripper {
+	// Currently we don't use any of the options available
+	applyInstrumentedRoundTripperOptions(opts)
+
+	return &instrumentedRoundTripper{delegate: delegate}
+}