Initial cloud-services repo - gateway service + pkg modules

services/gateway/websocket/connections.go

@@ -0,0 +1,166 @@
+package websocket
+
+import (
+	"context"
+	"encoding/json"
+	"sync"
+
+	"fiskerinc.com/modules/common"
+	"fiskerinc.com/modules/logger"
+	"fiskerinc.com/modules/scheduler"
+	"github.com/pkg/errors"
+	"github.com/robfig/cron"
+)
+
+func NewConnections() *Connections {
+	return &Connections{
+		sessions:   make(map[string]SessionInterface),
+		expiration: scheduler.Bucket[SessionInterface]{},
+	}
+}
+
+type Connections struct {
+	sessions   map[string]SessionInterface
+	expiration scheduler.Bucket[SessionInterface]
+	mu         sync.RWMutex
+}
+
+func (c *Connections) getSession(id string) (SessionInterface, bool) {
+	c.mu.RLock()
+	session, ok := c.sessions[id]
+	c.mu.RUnlock()
+	return session, ok
+}
+
+func (c *Connections) addSession(key string, session SessionInterface) {
+	c.mu.Lock()
+
+	c.sessions[key] = session
+
+	logger.At(logger.Info(), key, "conn").
+		Str("ip", session.GetIP()).
+		Int("connections", c.length()).
+		Msgf("added connection %s", key)
+
+	c.mu.Unlock()
+}
+
+func (c *Connections) deleteSession(session SessionInterface) {
+	c.mu.Lock()
+
+	key := session.Key()
+
+	delete(c.sessions, key)
+
+	logger.At(logger.Info(), key, "conn").
+		Str("ip", session.GetIP()).
+		Int("connections", c.length()).
+		Msgf("removed connection %s", key)
+
+	c.mu.Unlock()
+}
+
+// Add connection to map
+func (c *Connections) Add(session SessionInterface) error {
+	key := session.Key()
+
+	expiredSession, exists := c.getSession(key)
+	if exists {
+		expiredSession.SendMsgToClient(DuplicateConnectionMessage())
+		// if connection already exists, skip teardown when closing connection
+		// otherwise the car status will be changed to offline
+		expiredSession.SkipTeardown(true)
+		c.Remove(expiredSession)
+	}
+
+	c.addSession(key, session)
+	if exists && expiredSession != nil {
+		if expiredSession.GetType() == common.HMI.String() { // workaround for HMI sessions
+			// if connection already exists, skip teardown when closing connection
+			// otherwise the car status will be changed to offline
+			logger.At(logger.Info(), "Connections::checkIfExists schedule", key).Send()
+			c.Schedule(expiredSession)
+		} else {
+			expiredSession.Close()
+			logger.At(logger.Info(), key, "conn").Msgf("existing connection %s is closed", key)
+
+		}
+		logger.At(logger.Info(), key, "conn").Msgf("removing duplicate connection %s", key)
+
+	}
+
+	return nil
+}
+
+// Remove connection from map
+//
+//	if connection is not equal to the connection in map,
+//	does not remove
+func (c *Connections) Remove(session SessionInterface) error {
+	id := session.Key()
+
+	expiredSesssion, ok := c.getSession(id)
+	if !ok {
+		return missingWebsocketError(id)
+	}
+	if expiredSesssion != session {
+		return wrongSessionError(id)
+	}
+
+	c.deleteSession(session)
+
+	return nil
+}
+
+// Send to websocket connection
+func (c *Connections) SendMsgToClient(id string, message []byte) error {
+	session, ok := c.getSession(id)
+	if !ok {
+		return missingWebsocketError(id)
+	}
+
+	return session.SendMsgToClient(message)
+}
+
+func (c *Connections) length() int {
+	return len(c.sessions)
+}
+
+func missingWebsocketError(id string) error {
+	return errors.Errorf("no websocket connection found for ID: %v", id)
+}
+
+func wrongSessionError(id string) error {
+	return errors.Errorf("%v does not match with existing connection", id)
+}
+
+func DuplicateConnectionMessage() []byte {
+	m := common.Message{
+		Handler: "error",
+		Data: common.MessageString{
+			Message: "disconnected by duplicate ID",
+		},
+	}
+
+	p, _ := json.Marshal(m)
+	return p
+}
+func (c *Connections) Schedule(session SessionInterface) error {
+	logger.Info().Msgf("Scheduling session to expire in 6 min %s. type %s", session.GetID(), session.GetType())
+	c.expiration.Schedule(session)
+	return nil
+}
+
+func (c *Connections) RunExpiration(ctx context.Context) {
+	cr := cron.New()
+	cr.AddFunc("@every 30s", func() {
+		c.expiration.Process(func(session SessionInterface) {
+			logger.Debug().Msgf("RunExpiration::closing session %s ", session.Key())
+			session.Close()
+		})
+	})
+
+	cr.Start()
+	<-ctx.Done()
+	cr.Stop()
+}