Add Intermediate-Context header support for Talaria message metadata

device/device.go

@@ -100,6 +100,9 @@ type Interface interface {
 	// CloseReason returns the metadata explaining why a device was closed.  If this device
 	// is not closed, this method's return is undefined.
 	CloseReason() CloseReason
+
+	// IntermediateContext returns any additional information if sent by the device.
+	IntermediateContext() string
 }
 
 // device is the internal Interface implementation.  This type holds the internal
@@ -124,6 +127,8 @@ type device struct {
 	metadata *Metadata
 
 	closeReason atomic.Value
+
+	intermediateContext string
 }
 
 type deviceOptions struct {
@@ -320,3 +325,7 @@ func (d *device) CloseReason() CloseReason {
 
 	return CloseReason{}
 }
+
+func (d *device) IntermediateContext() string {
+	return d.intermediateContext
+}

device/manager.go

@@ -212,6 +212,7 @@ func (m *manager) Connect(response http.ResponseWriter, request *http.Request, r
 		Metadata:   metadata,
 		Logger:     m.logger,
 	})
+	d.intermediateContext = request.Header.Get("X-Intermediate-Context")
 
 	if allow, matchResults := m.filter.AllowConnection(d); !allow {
 		d.logger.Info("filter match found", zap.String("location", matchResults.Location), zap.String("key", matchResults.Key))

device/mocks.go

@@ -137,6 +137,10 @@ func (m *MockDevice) CloseReason() CloseReason {
 	return first
 }
 
+func (m *MockDevice) IntermediateContext() string {
+	return ""
+}
+
 func (m *MockDevice) Send(request *Request) (*Response, error) {
 	// nolint: typecheck
 	arguments := m.Called(request)