Reduce 500s (#1017)

* Try to avoid returning 500s on /send

* Don't return 500s from media API download requests

* Don't 500 on context errors

* Update sytest-whitelist

* Fix lint, add comments
This commit is contained in:
Neil Alexander 2020-05-13 13:01:45 +01:00 committed by GitHub
parent 5e9dce1c0c
commit ee140c9d6a
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@ -74,28 +74,17 @@ func Send(
util.GetLogger(httpReq.Context()).Infof("Received transaction %q containing %d PDUs, %d EDUs", txnID, len(t.PDUs), len(t.EDUs))
resp, err := t.processTransaction()
switch err.(type) {
// No error? Great! Send back a 200.
case nil:
return util.JSONResponse{
Code: http.StatusOK,
JSON: resp,
}
// Handle known error cases as we will return a 400 error for these.
case roomNotFoundError:
case unmarshalError:
case verifySigError:
// Handle unknown error cases. Sending 500 errors back should be a last
// resort as this can make other homeservers back off sending federation
// events.
default:
if err != nil {
util.GetLogger(httpReq.Context()).WithError(err).Error("t.processTransaction failed")
return jsonerror.InternalServerError()
}
// Return a 400 error for bad requests as fallen through from above.
// https://matrix.org/docs/spec/server_server/r0.1.3#put-matrix-federation-v1-send-txnid
// Status code 200:
// The result of processing the transaction. The server is to use this response
// even in the event of one or more PDUs failing to be processed.
return util.JSONResponse{
Code: http.StatusBadRequest,
JSON: jsonerror.BadJSON(err.Error()),
Code: http.StatusOK,
JSON: resp,
}
}
@ -135,30 +124,39 @@ func (t *txnReq) processTransaction() (*gomatrixserverlib.RespSend, error) {
}
if err := json.Unmarshal(pdu, &header); err != nil {
util.GetLogger(t.context).WithError(err).Warn("Transaction: Failed to extract room ID from event")
return nil, unmarshalError{err}
// We don't know the event ID at this point so we can't return the
// failure in the PDU results
continue
}
verReq := api.QueryRoomVersionForRoomRequest{RoomID: header.RoomID}
verRes := api.QueryRoomVersionForRoomResponse{}
if err := t.rsAPI.QueryRoomVersionForRoom(t.context, &verReq, &verRes); err != nil {
util.GetLogger(t.context).WithError(err).Warn("Transaction: Failed to query room version for room", verReq.RoomID)
return nil, roomNotFoundError{verReq.RoomID}
// We don't know the event ID at this point so we can't return the
// failure in the PDU results
continue
}
event, err := gomatrixserverlib.NewEventFromUntrustedJSON(pdu, verRes.RoomVersion)
if err != nil {
util.GetLogger(t.context).WithError(err).Warnf("Transaction: Failed to parse event JSON of event %q", event.EventID())
return nil, unmarshalError{err}
results[event.EventID()] = gomatrixserverlib.PDUResult{
Error: err.Error(),
}
continue
}
if err := gomatrixserverlib.VerifyAllEventSignatures(t.context, []gomatrixserverlib.Event{event}, t.keys); err != nil {
if err = gomatrixserverlib.VerifyAllEventSignatures(t.context, []gomatrixserverlib.Event{event}, t.keys); err != nil {
util.GetLogger(t.context).WithError(err).Warnf("Transaction: Couldn't validate signature of event %q", event.EventID())
return nil, verifySigError{event.EventID(), err}
results[event.EventID()] = gomatrixserverlib.PDUResult{
Error: err.Error(),
}
continue
}
pdus = append(pdus, event.Headered(verRes.RoomVersion))
}
// Process the events.
for _, e := range pdus {
err := t.processEvent(e.Unwrap(), true)
if err != nil {
if err := t.processEvent(e.Unwrap(), true); err != nil {
// If the error is due to the event itself being bad then we skip
// it and move onto the next event. We report an error so that the
// sender knows that we have skipped processing it.
@ -174,20 +172,17 @@ func (t *txnReq) processTransaction() (*gomatrixserverlib.RespSend, error) {
// receive another event referencing it.
// If we bail and stop processing then we risk wedging incoming
// transactions from that server forever.
switch err.(type) {
case roomNotFoundError:
case *gomatrixserverlib.NotAllowed:
case missingPrevEventsError:
default:
util.GetLogger(t.context).Warnf("Processing %s failed: %s", e.EventID(), err)
if isProcessingErrorFatal(err) {
// Any other error should be the result of a temporary error in
// our server so we should bail processing the transaction entirely.
util.GetLogger(t.context).Warnf("Processing %s failed fatally: %s", e.EventID(), err)
return nil, err
} else {
util.GetLogger(t.context).WithError(err).WithField("event_id", e.EventID()).Warn("Failed to process incoming federation event, skipping")
results[e.EventID()] = gomatrixserverlib.PDUResult{
Error: err.Error(),
}
}
results[e.EventID()] = gomatrixserverlib.PDUResult{
Error: err.Error(),
}
util.GetLogger(t.context).WithError(err).WithField("event_id", e.EventID()).Warn("Failed to process incoming federation event, skipping it.")
} else {
results[e.EventID()] = gomatrixserverlib.PDUResult{}
}
@ -198,6 +193,25 @@ func (t *txnReq) processTransaction() (*gomatrixserverlib.RespSend, error) {
return &gomatrixserverlib.RespSend{PDUs: results}, nil
}
// isProcessingErrorFatal returns true if the error is really bad and
// we should stop processing the transaction, and returns false if it
// is just some less serious error about a specific event.
func isProcessingErrorFatal(err error) bool {
switch err.(type) {
case roomNotFoundError:
case *gomatrixserverlib.NotAllowed:
case missingPrevEventsError:
default:
switch err {
case context.Canceled:
case context.DeadlineExceeded:
default:
return true
}
}
return false
}
type roomNotFoundError struct {
roomID string
}