Send device list updates to servers (outbound only) (#1237)

* Add QueryDeviceMessages to serve up device keys and stream IDs

* Consume key change events in fedsender

Don't yet send them to destinations as we haven't worked them out yet

* Send device list updates to all required servers

* Glue it all together

4 files changed, 64 insertions, 5 deletions

diff --git a/keyserver/api/api.go b/keyserver/api/api.go
index 080d0e5f..c864b328 100644
--- a/keyserver/api/api.go
+++ b/keyserver/api/api.go
@@ -32,6 +32,7 @@ type KeyInternalAPI interface {
 	QueryKeys(ctx context.Context, req *QueryKeysRequest, res *QueryKeysResponse)
 	QueryKeyChanges(ctx context.Context, req *QueryKeyChangesRequest, res *QueryKeyChangesResponse)
 	QueryOneTimeKeys(ctx context.Context, req *QueryOneTimeKeysRequest, res *QueryOneTimeKeysResponse)
+	QueryDeviceMessages(ctx context.Context, req *QueryDeviceMessagesRequest, res *QueryDeviceMessagesResponse)
 }
 
 // KeyError is returned if there was a problem performing/querying the server
@@ -188,3 +189,14 @@ type QueryOneTimeKeysResponse struct {
 	Count OneTimeKeysCount
 	Error *KeyError
 }
+
+type QueryDeviceMessagesRequest struct {
+	UserID string
+}
+
+type QueryDeviceMessagesResponse struct {
+	// The latest stream ID
+	StreamID int
+	Devices  []DeviceMessage
+	Error    *KeyError
+}
diff --git a/keyserver/internal/internal.go b/keyserver/internal/internal.go
index 9027cbf4..474f30ff 100644
--- a/keyserver/internal/internal.go
+++ b/keyserver/internal/internal.go
@@ -179,6 +179,24 @@ func (a *KeyInternalAPI) QueryOneTimeKeys(ctx context.Context, req *api.QueryOne
 	res.Count = *count
 }
 
+func (a *KeyInternalAPI) QueryDeviceMessages(ctx context.Context, req *api.QueryDeviceMessagesRequest, res *api.QueryDeviceMessagesResponse) {
+	msgs, err := a.DB.DeviceKeysForUser(ctx, req.UserID, nil)
+	if err != nil {
+		res.Error = &api.KeyError{
+			Err: fmt.Sprintf("failed to query DB for device keys: %s", err),
+		}
+		return
+	}
+	maxStreamID := 0
+	for _, m := range msgs {
+		if m.StreamID > maxStreamID {
+			maxStreamID = m.StreamID
+		}
+	}
+	res.Devices = msgs
+	res.StreamID = maxStreamID
+}
+
 func (a *KeyInternalAPI) QueryKeys(ctx context.Context, req *api.QueryKeysRequest, res *api.QueryKeysResponse) {
 	res.DeviceKeys = make(map[string]map[string]json.RawMessage)
 	res.Failures = make(map[string]interface{})
diff --git a/keyserver/inthttp/client.go b/keyserver/inthttp/client.go
index b65cbdaf..93b19051 100644
--- a/keyserver/inthttp/client.go
+++ b/keyserver/inthttp/client.go
@@ -27,11 +27,12 @@ import (
 
 // HTTP paths for the internal HTTP APIs
 const (
-	PerformUploadKeysPath = "/keyserver/performUploadKeys"
-	PerformClaimKeysPath  = "/keyserver/performClaimKeys"
-	QueryKeysPath         = "/keyserver/queryKeys"
-	QueryKeyChangesPath   = "/keyserver/queryKeyChanges"
-	QueryOneTimeKeysPath  = "/keyserver/queryOneTimeKeys"
+	PerformUploadKeysPath   = "/keyserver/performUploadKeys"
+	PerformClaimKeysPath    = "/keyserver/performClaimKeys"
+	QueryKeysPath           = "/keyserver/queryKeys"
+	QueryKeyChangesPath     = "/keyserver/queryKeyChanges"
+	QueryOneTimeKeysPath    = "/keyserver/queryOneTimeKeys"
+	QueryDeviceMessagesPath = "/keyserver/queryDeviceMessages"
 )
 
 // NewKeyServerClient creates a KeyInternalAPI implemented by talking to a HTTP POST API.
@@ -126,6 +127,23 @@ func (h *httpKeyInternalAPI) QueryOneTimeKeys(
 	}
 }
 
+func (h *httpKeyInternalAPI) QueryDeviceMessages(
+	ctx context.Context,
+	request *api.QueryDeviceMessagesRequest,
+	response *api.QueryDeviceMessagesResponse,
+) {
+	span, ctx := opentracing.StartSpanFromContext(ctx, "QueryDeviceMessages")
+	defer span.Finish()
+
+	apiURL := h.apiURL + QueryDeviceMessagesPath
+	err := httputil.PostJSON(ctx, span, h.httpClient, apiURL, request, response)
+	if err != nil {
+		response.Error = &api.KeyError{
+			Err: err.Error(),
+		}
+	}
+}
+
 func (h *httpKeyInternalAPI) QueryKeyChanges(
 	ctx context.Context,
 	request *api.QueryKeyChangesRequest,
diff --git a/keyserver/inthttp/server.go b/keyserver/inthttp/server.go
index 615b6f80..f0cd3038 100644
--- a/keyserver/inthttp/server.go
+++ b/keyserver/inthttp/server.go
@@ -69,6 +69,17 @@ func AddRoutes(internalAPIMux *mux.Router, s api.KeyInternalAPI) {
 			return util.JSONResponse{Code: http.StatusOK, JSON: &response}
 		}),
 	)
+	internalAPIMux.Handle(QueryDeviceMessagesPath,
+		httputil.MakeInternalAPI("queryDeviceMessages", func(req *http.Request) util.JSONResponse {
+			request := api.QueryDeviceMessagesRequest{}
+			response := api.QueryDeviceMessagesResponse{}
+			if err := json.NewDecoder(req.Body).Decode(&request); err != nil {
+				return util.MessageResponse(http.StatusBadRequest, err.Error())
+			}
+			s.QueryDeviceMessages(req.Context(), &request, &response)
+			return util.JSONResponse{Code: http.StatusOK, JSON: &response}
+		}),
+	)
 	internalAPIMux.Handle(QueryKeyChangesPath,
 		httputil.MakeInternalAPI("queryKeyChanges", func(req *http.Request) util.JSONResponse {
 			request := api.QueryKeyChangesRequest{}