From df353c6244ff5fd881e5cca629f27eac4f011d90 Mon Sep 17 00:00:00 2001
From: andig <andi@evcc.io>
Date: Sun, 22 Sep 2024 18:26:53 +0200
Subject: [PATCH] Ocpp: serialise setup (#16262)

---
 charger/ocpp.go          | 42 ++++++++++++++--------------------
 charger/ocpp/cs.go       | 49 ++++++++++++++++++++++++++++++++++------
 charger/ocpp/instance.go |  1 +
 3 files changed, 60 insertions(+), 32 deletions(-)

diff --git a/charger/ocpp.go b/charger/ocpp.go
index e2a333973..84b42c6ad 100644
--- a/charger/ocpp.go
+++ b/charger/ocpp.go
@@ -120,34 +120,26 @@ func NewOCPP(id string, connector int, idTag string,
 	stackLevelZero, remoteStart bool,
 	connectTimeout time.Duration,
 ) (*OCPP, error) {
-	unit := "ocpp"
-	if id != "" {
-		unit = id
-	}
-	unit = fmt.Sprintf("%s-%d", unit, connector)
+	log := util.NewLogger(fmt.Sprintf("%s-%d", lo.CoalesceOrEmpty(id, "ocpp"), connector))
 
-	log := util.NewLogger(unit)
+	cp, err := ocpp.Instance().RegisterChargepoint(id,
+		func() *ocpp.CP {
+			return ocpp.NewChargePoint(log, id)
+		},
+		func(cp *ocpp.CP) error {
+			log.DEBUG.Printf("waiting for chargepoint: %v", connectTimeout)
 
-	cp, err := ocpp.Instance().ChargepointByID(id)
+			select {
+			case <-time.After(connectTimeout):
+				return api.ErrTimeout
+			case <-cp.HasConnected():
+			}
+
+			return cp.Setup(meterValues, meterInterval)
+		},
+	)
 	if err != nil {
-		cp = ocpp.NewChargePoint(log, id)
-
-		// should not error
-		if err := ocpp.Instance().Register(id, cp); err != nil {
-			return nil, err
-		}
-
-		log.DEBUG.Printf("waiting for chargepoint: %v", connectTimeout)
-
-		select {
-		case <-time.After(connectTimeout):
-			return nil, api.ErrTimeout
-		case <-cp.HasConnected():
-		}
-
-		if err := cp.Setup(meterValues, meterInterval); err != nil {
-			return nil, err
-		}
+		return nil, err
 	}
 
 	if cp.NumberOfConnectors > 0 && connector > cp.NumberOfConnectors {
diff --git a/charger/ocpp/cs.go b/charger/ocpp/cs.go
index 72be4ac00..565c63f30 100644
--- a/charger/ocpp/cs.go
+++ b/charger/ocpp/cs.go
@@ -14,26 +14,35 @@ type CS struct {
 	log *util.Logger
 	ocpp16.CentralSystem
 	cps   map[string]*CP
+	init  map[string]*sync.Mutex
 	txnId int
 }
 
 // Register registers a charge point with the central system.
 // The charge point identified by id may already be connected in which case initial connection is triggered.
-func (cs *CS) Register(id string, cp *CP) error {
+func (cs *CS) register(id string, new *CP) error {
 	cs.mu.Lock()
 	defer cs.mu.Unlock()
 
-	if _, ok := cs.cps[id]; ok && id == "" {
+	cp, ok := cs.cps[id]
+
+	// case 1: charge point neither registered nor physically connected
+	if !ok {
+		cs.cps[id] = new
+		return nil
+	}
+
+	// case 2: duplicate registration of id empty
+	if id == "" {
 		return errors.New("cannot have >1 charge point with empty station id")
 	}
 
-	// trigger unknown charge point connected
-	if unknown, ok := cs.cps[id]; ok && unknown == nil {
-		cp.connect(true)
+	// case 3: charge point not registered but physically already connected
+	if cp == nil {
+		cs.cps[id] = new
+		new.connect(true)
 	}
 
-	cs.cps[id] = cp
-
 	return nil
 }
 
@@ -58,6 +67,32 @@ func (cs *CS) ChargepointByID(id string) (*CP, error) {
 	return cp, nil
 }
 
+func (cs *CS) RegisterChargepoint(id string, newfun func() *CP, init func(*CP) error) (*CP, error) {
+	cs.mu.Lock()
+	cpmu, ok := cs.init[id]
+	if !ok {
+		cpmu = new(sync.Mutex)
+		cs.init[id] = cpmu
+	}
+	cs.mu.Unlock()
+
+	// serialise on chargepoint id
+	cpmu.Lock()
+	defer cpmu.Unlock()
+
+	cp, err := cs.ChargepointByID(id)
+	if err != nil {
+		cp = newfun()
+	}
+
+	// should not error
+	if err := cs.register(id, cp); err != nil {
+		return nil, err
+	}
+
+	return cp, init(cp)
+}
+
 // NewChargePoint implements ocpp16.ChargePointConnectionHandler
 func (cs *CS) NewChargePoint(chargePoint ocpp16.ChargePointConnection) {
 	cs.mu.Lock()
diff --git a/charger/ocpp/instance.go b/charger/ocpp/instance.go
index ec6315f13..64086802a 100644
--- a/charger/ocpp/instance.go
+++ b/charger/ocpp/instance.go
@@ -41,6 +41,7 @@ func Instance() *CS {
 		instance = &CS{
 			log:           log,
 			cps:           make(map[string]*CP),
+			init:          make(map[string]*sync.Mutex),
 			CentralSystem: cs,
 			txnId:         int(time.Now().UTC().Unix()),
 		}