bigbluebutton-Github/bbb-graphql-middleware/internal/hasura/conn/reader/reader.go

259 lines
8.7 KiB
Go

package reader
import (
"bbb-graphql-middleware/internal/common"
"bbb-graphql-middleware/internal/hasura/retransmiter"
"bbb-graphql-middleware/internal/msgpatch"
"bytes"
"context"
"encoding/json"
"errors"
"github.com/prometheus/client_golang/prometheus"
log "github.com/sirupsen/logrus"
"hash/crc32"
"nhooyr.io/websocket"
"sync"
)
// HasuraConnectionReader consumes messages from Hasura connection and add send to the browser channel
func HasuraConnectionReader(hc *common.HasuraConnection, wg *sync.WaitGroup) {
log := log.WithField("_routine", "HasuraConnectionReader").WithField("browserConnectionId", hc.BrowserConn.Id).WithField("hasuraConnectionId", hc.Id)
defer log.Debugf("finished")
log.Debugf("starting")
defer wg.Done()
defer hc.ContextCancelFunc()
for {
messageType, message, err := hc.Websocket.Read(hc.Context)
var closeError *websocket.CloseError
if err != nil {
if errors.Is(err, context.Canceled) {
log.Debugf("Closing Hasura ws connection as Context was cancelled!")
} else if errors.As(err, &closeError) {
hc.WebsocketCloseError = closeError
log.Debug("WebSocket connection closed: status = %v, reason = %s", closeError.Code, closeError.Reason)
//TODO check if it should send {"type":"connection_error","payload":"Authentication hook unauthorized this request"}
} else {
if websocket.CloseStatus(err) == -1 {
//It doesn't have a CloseError, it will reconnect do Hasura
} else {
//In case Hasura sent an CloseError, it will forward it to browser and disconnect
hc.WebsocketCloseError = &websocket.CloseError{
Code: websocket.CloseStatus(err),
Reason: "Graphql connection closed with error" + err.Error(),
}
}
log.Debugf("Error reading message from Hasura: %v", err)
}
return
}
if messageType != websocket.MessageText {
log.Warnf("received non-text message: %v", messageType)
continue
}
log.Tracef("received from hasura: %s", string(message))
handleMessageReceivedFromHasura(hc, message)
}
}
var QueryIdPlaceholderInBytes = []byte("--------------QUERY-ID--------------") //36 chars
func handleMessageReceivedFromHasura(hc *common.HasuraConnection, message []byte) {
type HasuraMessageInfo struct {
Type string `json:"type"`
ID string `json:"id"`
}
var hasuraMessageInfo HasuraMessageInfo
err := json.Unmarshal(message, &hasuraMessageInfo)
if err != nil {
log.Errorf("failed to unmarshal message: %v", err)
return
}
queryIdReplacementApplied := false
queryIdInBytes := []byte(hasuraMessageInfo.ID)
//Check if subscription is still active!
if hasuraMessageInfo.ID != "" {
hc.BrowserConn.ActiveSubscriptionsMutex.RLock()
subscription, ok := hc.BrowserConn.ActiveSubscriptions[hasuraMessageInfo.ID]
hc.BrowserConn.ActiveSubscriptionsMutex.RUnlock()
if !ok {
log.Debugf("Subscription with Id %s doesn't exist anymore, skipping response.", hasuraMessageInfo.ID)
return
}
//When Hasura send msg type "complete", this query is finished
if hasuraMessageInfo.Type == "complete" {
handleCompleteMessage(hc, hasuraMessageInfo.ID)
}
if hasuraMessageInfo.Type == "next" {
common.GqlReceivedDataCounter.
With(prometheus.Labels{
"type": string(subscription.Type),
"operationName": subscription.OperationName}).
Inc()
}
if hasuraMessageInfo.Type == "next" &&
subscription.Type == common.Subscription {
//Remove queryId from message
message = bytes.Replace(message, queryIdInBytes, QueryIdPlaceholderInBytes, 1)
queryIdReplacementApplied = true
isDifferentFromPreviousMessage := handleSubscriptionMessage(hc, &message, subscription, hasuraMessageInfo.ID)
//Stop processing case it is the same message (probably is a reconnection with Hasura)
if !isDifferentFromPreviousMessage {
return
}
}
//Set last cursor value for stream
if subscription.Type == common.Streaming {
//Remove queryId from message
messageWithoutId := bytes.Replace(message, queryIdInBytes, QueryIdPlaceholderInBytes, 1)
handleStreamingMessage(hc, messageWithoutId, subscription, hasuraMessageInfo.ID)
}
}
// Retransmit the subscription start commands when hasura confirms the connection
// this is useful in case of a connection invalidation
if hasuraMessageInfo.Type == "connection_ack" {
handleConnectionAckMessage(hc, message)
} else {
if queryIdReplacementApplied {
message = bytes.Replace(message, QueryIdPlaceholderInBytes, queryIdInBytes, 1)
}
// Forward the message to browser
hc.BrowserConn.FromHasuraToBrowserChannel.Send(message)
}
}
func handleSubscriptionMessage(hc *common.HasuraConnection, message *[]byte, subscription common.GraphQlSubscription, queryId string) bool {
dataChecksum, messageDataKey, messageData := getHasuraMessage(*message, subscription)
//Check whether ReceivedData is different from the LastReceivedData
//Otherwise stop forwarding this message
if subscription.LastReceivedDataChecksum == dataChecksum {
return false
}
lastDataChecksumWas := subscription.LastReceivedDataChecksum
lastReceivedDataWas := subscription.LastReceivedData
cacheKey := mergeUint32(subscription.LastReceivedDataChecksum, dataChecksum)
//Store LastReceivedData Checksum
subscription.LastReceivedData = messageData
subscription.LastReceivedDataChecksum = dataChecksum
hc.BrowserConn.ActiveSubscriptionsMutex.Lock()
hc.BrowserConn.ActiveSubscriptions[queryId] = subscription
hc.BrowserConn.ActiveSubscriptionsMutex.Unlock()
//Apply msg patch when it supports it
if subscription.JsonPatchSupported {
*message = msgpatch.GetPatchedMessage(*message, messageDataKey, lastReceivedDataWas, messageData, cacheKey, lastDataChecksumWas, dataChecksum)
}
return true
}
func mergeUint32(a, b uint32) uint32 {
return (a << 16) | (b >> 16)
}
func handleStreamingMessage(hc *common.HasuraConnection, message []byte, subscription common.GraphQlSubscription, queryId string) {
lastCursor := common.GetLastStreamCursorValueFromReceivedMessage(message, subscription.StreamCursorField)
if lastCursor != nil && subscription.StreamCursorCurrValue != lastCursor {
subscription.StreamCursorCurrValue = lastCursor
hc.BrowserConn.ActiveSubscriptionsMutex.Lock()
hc.BrowserConn.ActiveSubscriptions[queryId] = subscription
hc.BrowserConn.ActiveSubscriptionsMutex.Unlock()
}
}
func handleCompleteMessage(hc *common.HasuraConnection, queryId string) {
hc.BrowserConn.ActiveSubscriptionsMutex.Lock()
queryType := hc.BrowserConn.ActiveSubscriptions[queryId].Type
operationName := hc.BrowserConn.ActiveSubscriptions[queryId].OperationName
delete(hc.BrowserConn.ActiveSubscriptions, queryId)
hc.BrowserConn.ActiveSubscriptionsMutex.Unlock()
log.Debugf("%s (%s) with Id %s finished by Hasura.", queryType, operationName, queryId)
}
func handleConnectionAckMessage(hc *common.HasuraConnection, message []byte) {
log.Debugf("Received connection_ack")
//Hasura connection was initialized, now it's able to send new messages to Hasura
hc.BrowserConn.FromBrowserToHasuraChannel.UnfreezeChannel()
//Avoid to send `connection_ack` to the browser when it's a reconnection
if hc.BrowserConn.ConnAckSentToBrowser == false {
hc.BrowserConn.FromHasuraToBrowserChannel.Send(message)
hc.BrowserConn.ConnAckSentToBrowser = true
}
go retransmiter.RetransmitSubscriptionStartMessages(hc)
}
func getHasuraMessage(message []byte, subscription common.GraphQlSubscription) (uint32, string, common.HasuraMessage) {
dataChecksum := crc32.ChecksumIEEE(message)
common.GlobalCacheLocks.Lock(dataChecksum)
defer common.GlobalCacheLocks.Unlock(dataChecksum)
dataKey, hasuraMessage, dataMapExists := common.GetHasuraMessageCache(dataChecksum)
if dataMapExists {
return dataChecksum, dataKey, hasuraMessage
}
err := json.Unmarshal(message, &hasuraMessage)
if err != nil {
log.Fatalf("Error unmarshalling JSON: %v", err)
}
for key := range hasuraMessage.Payload.Data {
dataKey = key
break
}
common.StoreHasuraMessageCache(dataChecksum, dataKey, hasuraMessage)
//Add Prometheus metrics only once for each dataChecksum
dataSize := len(string(message))
common.GqlReceivedDataPayloadSize.
With(prometheus.Labels{
"type": string(subscription.Type),
"operationName": subscription.OperationName}).
Observe(float64(dataSize))
if common.PrometheusAdvancedMetricsEnabled {
// Decode the JSON array into raw messages
var rawMessages []json.RawMessage
err := json.Unmarshal(hasuraMessage.Payload.Data[dataKey], &rawMessages)
if err == nil {
// Get the length of the array
dataLength := len(rawMessages)
common.GqlReceivedDataPayloadLength.
With(prometheus.Labels{
"type": string(subscription.Type),
"operationName": subscription.OperationName}).
Observe(float64(dataLength))
}
}
return dataChecksum, dataKey, hasuraMessage
}