Generic-based internal HTTP API (#2626)

* Generic-based internal HTTP API (tested out on a few endpoints in the federation API)

* Add `PerformInvite`

* More tweaks

* Fix metric name

* Fix LookupStateIDs

* Lots of changes to clients

* Some serverside stuff

* Some error handling

* Use paths as metric names

* Revert "Use paths as metric names"

This reverts commit a9323a6a343f5ce6461a2e5bd570fe06465f1b15.

* Namespace metric names

* Remove duplicate entry

* Remove another duplicate entry

* Tweak error handling

* Some more tweaks

* Update error behaviour

* Some more error tweaking

* Fix API path for `PerformDeleteKeys`

* Fix another path

* Tweak federation client proxying

* Fix another path

* Don't return typed nils

* Some more tweaks, not that it makes any difference

* Tweak federation client proxying

* Maybe fix the key backup test

10 files changed, 68 insertions, 24 deletions

diff --git a/clientapi/jsonerror/jsonerror.go b/clientapi/jsonerror/jsonerror.go
index 70bac61d..be7d13a9 100644
--- a/clientapi/jsonerror/jsonerror.go
+++ b/clientapi/jsonerror/jsonerror.go
@@ -15,11 +15,13 @@
 package jsonerror
 
 import (
+	"context"
 	"fmt"
 	"net/http"
 
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/matrix-org/util"
+	"github.com/sirupsen/logrus"
 )
 
 // MatrixError represents the "standard error response" in Matrix.
@@ -213,3 +215,15 @@ func NotTrusted(serverName string) *MatrixError {
 		Err:     fmt.Sprintf("Untrusted server '%s'", serverName),
 	}
 }
+
+// InternalAPIError is returned when Dendrite failed to reach an internal API.
+func InternalAPIError(ctx context.Context, err error) util.JSONResponse {
+	logrus.WithContext(ctx).WithError(err).Error("Error reaching an internal API")
+	return util.JSONResponse{
+		Code: http.StatusInternalServerError,
+		JSON: &MatrixError{
+			ErrCode: "M_INTERNAL_SERVER_ERROR",
+			Err:     "Dendrite encountered an error reaching an internal API.",
+		},
+	}
+}
diff --git a/clientapi/routing/admin.go b/clientapi/routing/admin.go
index 523b88c9..a8dd0e64 100644
--- a/clientapi/routing/admin.go
+++ b/clientapi/routing/admin.go
@@ -30,13 +30,15 @@ func AdminEvacuateRoom(req *http.Request, device *userapi.Device, rsAPI roomserv
 		}
 	}
 	res := &roomserverAPI.PerformAdminEvacuateRoomResponse{}
-	rsAPI.PerformAdminEvacuateRoom(
+	if err := rsAPI.PerformAdminEvacuateRoom(
 		req.Context(),
 		&roomserverAPI.PerformAdminEvacuateRoomRequest{
 			RoomID: roomID,
 		},
 		res,
-	)
+	); err != nil {
+		return util.ErrorResponse(err)
+	}
 	if err := res.Error; err != nil {
 		return err.JSONResponse()
 	}
@@ -67,13 +69,15 @@ func AdminEvacuateUser(req *http.Request, device *userapi.Device, rsAPI roomserv
 		}
 	}
 	res := &roomserverAPI.PerformAdminEvacuateUserResponse{}
-	rsAPI.PerformAdminEvacuateUser(
+	if err := rsAPI.PerformAdminEvacuateUser(
 		req.Context(),
 		&roomserverAPI.PerformAdminEvacuateUserRequest{
 			UserID: userID,
 		},
 		res,
-	)
+	); err != nil {
+		return jsonerror.InternalAPIError(req.Context(), err)
+	}
 	if err := res.Error; err != nil {
 		return err.JSONResponse()
 	}
diff --git a/clientapi/routing/createroom.go b/clientapi/routing/createroom.go
index 3f92b7ba..87490863 100644
--- a/clientapi/routing/createroom.go
+++ b/clientapi/routing/createroom.go
@@ -556,10 +556,12 @@ func createRoom(
 	if r.Visibility == "public" {
 		// expose this room in the published room list
 		var pubRes roomserverAPI.PerformPublishResponse
-		rsAPI.PerformPublish(ctx, &roomserverAPI.PerformPublishRequest{
+		if err := rsAPI.PerformPublish(ctx, &roomserverAPI.PerformPublishRequest{
 			RoomID:     roomID,
 			Visibility: "public",
-		}, &pubRes)
+		}, &pubRes); err != nil {
+			return jsonerror.InternalAPIError(ctx, err)
+		}
 		if pubRes.Error != nil {
 			// treat as non-fatal since the room is already made by this point
 			util.GetLogger(ctx).WithError(pubRes.Error).Error("failed to visibility:public")
diff --git a/clientapi/routing/directory.go b/clientapi/routing/directory.go
index 53ba3f19..836d9e15 100644
--- a/clientapi/routing/directory.go
+++ b/clientapi/routing/directory.go
@@ -302,10 +302,12 @@ func SetVisibility(
 	}
 
 	var publishRes roomserverAPI.PerformPublishResponse
-	rsAPI.PerformPublish(req.Context(), &roomserverAPI.PerformPublishRequest{
+	if err := rsAPI.PerformPublish(req.Context(), &roomserverAPI.PerformPublishRequest{
 		RoomID:     roomID,
 		Visibility: v.Visibility,
-	}, &publishRes)
+	}, &publishRes); err != nil {
+		return jsonerror.InternalAPIError(req.Context(), err)
+	}
 	if publishRes.Error != nil {
 		util.GetLogger(req.Context()).WithError(publishRes.Error).Error("PerformPublish failed")
 		return publishRes.Error.JSONResponse()
diff --git a/clientapi/routing/joinroom.go b/clientapi/routing/joinroom.go
index 4e6acebc..c50e552b 100644
--- a/clientapi/routing/joinroom.go
+++ b/clientapi/routing/joinroom.go
@@ -81,8 +81,9 @@ func JoinRoomByIDOrAlias(
 	done := make(chan util.JSONResponse, 1)
 	go func() {
 		defer close(done)
-		rsAPI.PerformJoin(req.Context(), &joinReq, &joinRes)
-		if joinRes.Error != nil {
+		if err := rsAPI.PerformJoin(req.Context(), &joinReq, &joinRes); err != nil {
+			done <- jsonerror.InternalAPIError(req.Context(), err)
+		} else if joinRes.Error != nil {
 			done <- joinRes.Error.JSONResponse()
 		} else {
 			done <- util.JSONResponse{
diff --git a/clientapi/routing/key_backup.go b/clientapi/routing/key_backup.go
index 28c80415..b6f8fe1b 100644
--- a/clientapi/routing/key_backup.go
+++ b/clientapi/routing/key_backup.go
@@ -91,10 +91,12 @@ func CreateKeyBackupVersion(req *http.Request, userAPI userapi.ClientUserAPI, de
 // Implements GET  /_matrix/client/r0/room_keys/version and GET /_matrix/client/r0/room_keys/version/{version}
 func KeyBackupVersion(req *http.Request, userAPI userapi.ClientUserAPI, device *userapi.Device, version string) util.JSONResponse {
 	var queryResp userapi.QueryKeyBackupResponse
-	userAPI.QueryKeyBackup(req.Context(), &userapi.QueryKeyBackupRequest{
+	if err := userAPI.QueryKeyBackup(req.Context(), &userapi.QueryKeyBackupRequest{
 		UserID:  device.UserID,
 		Version: version,
-	}, &queryResp)
+	}, &queryResp); err != nil {
+		return jsonerror.InternalAPIError(req.Context(), err)
+	}
 	if queryResp.Error != "" {
 		return util.ErrorResponse(fmt.Errorf("QueryKeyBackup: %s", queryResp.Error))
 	}
@@ -233,13 +235,15 @@ func GetBackupKeys(
 	req *http.Request, userAPI userapi.ClientUserAPI, device *userapi.Device, version, roomID, sessionID string,
 ) util.JSONResponse {
 	var queryResp userapi.QueryKeyBackupResponse
-	userAPI.QueryKeyBackup(req.Context(), &userapi.QueryKeyBackupRequest{
+	if err := userAPI.QueryKeyBackup(req.Context(), &userapi.QueryKeyBackupRequest{
 		UserID:           device.UserID,
 		Version:          version,
 		ReturnKeys:       true,
 		KeysForRoomID:    roomID,
 		KeysForSessionID: sessionID,
-	}, &queryResp)
+	}, &queryResp); err != nil {
+		return jsonerror.InternalAPIError(req.Context(), err)
+	}
 	if queryResp.Error != "" {
 		return util.ErrorResponse(fmt.Errorf("QueryKeyBackup: %s", queryResp.Error))
 	}
diff --git a/clientapi/routing/key_crosssigning.go b/clientapi/routing/key_crosssigning.go
index 8fbb86f7..2570db09 100644
--- a/clientapi/routing/key_crosssigning.go
+++ b/clientapi/routing/key_crosssigning.go
@@ -72,7 +72,9 @@ func UploadCrossSigningDeviceKeys(
 	sessions.addCompletedSessionStage(sessionID, authtypes.LoginTypePassword)
 
 	uploadReq.UserID = device.UserID
-	keyserverAPI.PerformUploadDeviceKeys(req.Context(), &uploadReq.PerformUploadDeviceKeysRequest, uploadRes)
+	if err := keyserverAPI.PerformUploadDeviceKeys(req.Context(), &uploadReq.PerformUploadDeviceKeysRequest, uploadRes); err != nil {
+		return jsonerror.InternalAPIError(req.Context(), err)
+	}
 
 	if err := uploadRes.Error; err != nil {
 		switch {
@@ -114,7 +116,9 @@ func UploadCrossSigningDeviceSignatures(req *http.Request, keyserverAPI api.Clie
 	}
 
 	uploadReq.UserID = device.UserID
-	keyserverAPI.PerformUploadDeviceSignatures(req.Context(), uploadReq, uploadRes)
+	if err := keyserverAPI.PerformUploadDeviceSignatures(req.Context(), uploadReq, uploadRes); err != nil {
+		return jsonerror.InternalAPIError(req.Context(), err)
+	}
 
 	if err := uploadRes.Error; err != nil {
 		switch {
diff --git a/clientapi/routing/keys.go b/clientapi/routing/keys.go
index fdda34a5..b7a76b47 100644
--- a/clientapi/routing/keys.go
+++ b/clientapi/routing/keys.go
@@ -62,7 +62,9 @@ func UploadKeys(req *http.Request, keyAPI api.ClientKeyAPI, device *userapi.Devi
 	}
 
 	var uploadRes api.PerformUploadKeysResponse
-	keyAPI.PerformUploadKeys(req.Context(), uploadReq, &uploadRes)
+	if err := keyAPI.PerformUploadKeys(req.Context(), uploadReq, &uploadRes); err != nil {
+		return util.ErrorResponse(err)
+	}
 	if uploadRes.Error != nil {
 		util.GetLogger(req.Context()).WithError(uploadRes.Error).Error("Failed to PerformUploadKeys")
 		return jsonerror.InternalServerError()
@@ -107,12 +109,14 @@ func QueryKeys(req *http.Request, keyAPI api.ClientKeyAPI, device *userapi.Devic
 		return *resErr
 	}
 	queryRes := api.QueryKeysResponse{}
-	keyAPI.QueryKeys(req.Context(), &api.QueryKeysRequest{
+	if err := keyAPI.QueryKeys(req.Context(), &api.QueryKeysRequest{
 		UserID:        device.UserID,
 		UserToDevices: r.DeviceKeys,
 		Timeout:       r.GetTimeout(),
 		// TODO: Token?
-	}, &queryRes)
+	}, &queryRes); err != nil {
+		return util.ErrorResponse(err)
+	}
 	return util.JSONResponse{
 		Code: 200,
 		JSON: map[string]interface{}{
@@ -145,10 +149,12 @@ func ClaimKeys(req *http.Request, keyAPI api.ClientKeyAPI) util.JSONResponse {
 		return *resErr
 	}
 	claimRes := api.PerformClaimKeysResponse{}
-	keyAPI.PerformClaimKeys(req.Context(), &api.PerformClaimKeysRequest{
+	if err := keyAPI.PerformClaimKeys(req.Context(), &api.PerformClaimKeysRequest{
 		OneTimeKeys: r.OneTimeKeys,
 		Timeout:     r.GetTimeout(),
-	}, &claimRes)
+	}, &claimRes); err != nil {
+		return jsonerror.InternalAPIError(req.Context(), err)
+	}
 	if claimRes.Error != nil {
 		util.GetLogger(req.Context()).WithError(claimRes.Error).Error("failed to PerformClaimKeys")
 		return jsonerror.InternalServerError()
diff --git a/clientapi/routing/peekroom.go b/clientapi/routing/peekroom.go
index d0eeccf1..9b2592eb 100644
--- a/clientapi/routing/peekroom.go
+++ b/clientapi/routing/peekroom.go
@@ -17,6 +17,7 @@ package routing
 import (
 	"net/http"
 
+	"github.com/matrix-org/dendrite/clientapi/jsonerror"
 	roomserverAPI "github.com/matrix-org/dendrite/roomserver/api"
 	"github.com/matrix-org/dendrite/userapi/api"
 	"github.com/matrix-org/gomatrixserverlib"
@@ -54,7 +55,9 @@ func PeekRoomByIDOrAlias(
 	}
 
 	// Ask the roomserver to perform the peek.
-	rsAPI.PerformPeek(req.Context(), &peekReq, &peekRes)
+	if err := rsAPI.PerformPeek(req.Context(), &peekReq, &peekRes); err != nil {
+		return util.ErrorResponse(err)
+	}
 	if peekRes.Error != nil {
 		return peekRes.Error.JSONResponse()
 	}
@@ -89,7 +92,9 @@ func UnpeekRoomByID(
 	}
 	unpeekRes := roomserverAPI.PerformUnpeekResponse{}
 
-	rsAPI.PerformUnpeek(req.Context(), &unpeekReq, &unpeekRes)
+	if err := rsAPI.PerformUnpeek(req.Context(), &unpeekReq, &unpeekRes); err != nil {
+		return jsonerror.InternalAPIError(req.Context(), err)
+	}
 	if unpeekRes.Error != nil {
 		return unpeekRes.Error.JSONResponse()
 	}
diff --git a/clientapi/routing/upgrade_room.go b/clientapi/routing/upgrade_room.go
index 744e2d88..34c7eb00 100644
--- a/clientapi/routing/upgrade_room.go
+++ b/clientapi/routing/upgrade_room.go
@@ -64,7 +64,9 @@ func UpgradeRoom(
 	}
 	upgradeResp := roomserverAPI.PerformRoomUpgradeResponse{}
 
-	rsAPI.PerformRoomUpgrade(req.Context(), &upgradeReq, &upgradeResp)
+	if err := rsAPI.PerformRoomUpgrade(req.Context(), &upgradeReq, &upgradeResp); err != nil {
+		return jsonerror.InternalAPIError(req.Context(), err)
+	}
 
 	if upgradeResp.Error != nil {
 		if upgradeResp.Error.Code == roomserverAPI.PerformErrorNoRoom {