Ocpp: cache and re-use initial status (2nd attempt)

charger/ocpp/cp_setup.go

@@ -158,8 +158,20 @@ func (cp *CP) Setup(meterValues string, meterInterval time.Duration) error {
 
 	// trigger status for all connectors
 	if cp.HasRemoteTriggerFeature {
-		if err := cp.TriggerMessageRequest(0, core.StatusNotificationFeatureName); err != nil {
-			cp.log.WARN.Printf("failed triggering StatusNotification: %v", err)
+		var ok bool
+
+		// apply cached status if available
+		instance.WithChargepointStatusByID(cp.id, func(status *core.StatusNotificationRequest) {
+			if _, err := cp.OnStatusNotification(status); err == nil {
+				ok = true
+			}
+		})
+
+		// only trigger if we don't already have a status
+		if !ok {
+			if err := cp.TriggerMessageRequest(0, core.StatusNotificationFeatureName); err != nil {
+				cp.log.WARN.Printf("failed triggering StatusNotification: %v", err)
+			}
 		}
 	}
 

charger/ocpp/cs.go

@@ -8,45 +8,24 @@ import (
 
 	"github.com/evcc-io/evcc/util"
 	ocpp16 "github.com/lorenzodonini/ocpp-go/ocpp1.6"
+	"github.com/lorenzodonini/ocpp-go/ocpp1.6/core"
 )
 
+type registration struct {
+	mu     sync.RWMutex
+	setup  sync.RWMutex                    // serialises chargepoint setup
+	cp     *CP                             // guarded by setup and CS mutexes
+	status *core.StatusNotificationRequest // guarded by mu mutex
+}
+
 type CS struct {
-	mu  sync.Mutex
-	log *util.Logger
 	ocpp16.CentralSystem
-	cps   map[string]*CP
-	init  map[string]*sync.Mutex
+	mu    sync.Mutex
+	log   *util.Logger
+	regs  map[string]*registration // guarded by mu mutex
 	txnId atomic.Int64
 }
 
-// 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, new *CP) error {
-	cs.mu.Lock()
-	defer cs.mu.Unlock()
-
-	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")
-	}
-
-	// case 3: charge point not registered but physically already connected
-	if cp == nil {
-		cs.cps[id] = new
-		new.connect(true)
-	}
-
-	return nil
-}
-
 // errorHandler logs error channel
 func (cs *CS) errorHandler(errC <-chan error) {
 	for err := range errC {
@@ -58,38 +37,67 @@ func (cs *CS) ChargepointByID(id string) (*CP, error) {
 	cs.mu.Lock()
 	defer cs.mu.Unlock()
 
-	cp, ok := cs.cps[id]
+	reg, ok := cs.regs[id]
 	if !ok {
 		return nil, fmt.Errorf("unknown charge point: %s", id)
 	}
-	if cp == nil {
+	if reg.cp == nil {
 		return nil, fmt.Errorf("charge point not configured: %s", id)
 	}
-	return cp, nil
+	return reg.cp, nil
 }
 
+func (cs *CS) WithChargepointStatusByID(id string, fun func(status *core.StatusNotificationRequest)) {
+	cs.mu.Lock()
+	defer cs.mu.Unlock()
+
+	if reg, ok := cs.regs[id]; ok {
+		reg.mu.RLock()
+		if reg.status != nil {
+			fun(reg.status)
+		}
+		reg.mu.RUnlock()
+	}
+}
+
+// RegisterChargepoint registers a charge point with the central system of returns an already registered charge point
 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
+
+	// prepare shadow state
+	reg, registered := cs.regs[id]
+	if !registered {
+		reg = new(registration)
+		cs.regs[id] = reg
 	}
-	cs.mu.Unlock()
 
 	// serialise on chargepoint id
-	cpmu.Lock()
-	defer cpmu.Unlock()
+	reg.setup.Lock()
+	defer reg.setup.Unlock()
+
+	cp := reg.cp
+
+	cs.mu.Unlock()
+
+	// setup already completed?
+	if cp != nil {
+		// duplicate registration of id empty
+		if id == "" {
+			return nil, errors.New("cannot have >1 charge point with empty station id")
+		}
 
-	// already registered?
-	if cp, err := cs.ChargepointByID(id); err == nil {
 		return cp, nil
 	}
 
-	// first time- registration should not error
-	cp := newfun()
-	if err := cs.register(id, cp); err != nil {
-		return nil, err
+	// first time- create the charge point
+	cp = newfun()
+
+	cs.mu.Lock()
+	reg.cp = cp
+	cs.mu.Unlock()
+
+	if registered {
+		cp.connect(true)
 	}
 
 	return cp, init(cp)
@@ -101,28 +109,29 @@ func (cs *CS) NewChargePoint(chargePoint ocpp16.ChargePointConnection) {
 	defer cs.mu.Unlock()
 
 	// check for configured charge point
-	cp, ok := cs.cps[chargePoint.ID()]
+	reg, ok := cs.regs[chargePoint.ID()]
 	if ok {
 		cs.log.DEBUG.Printf("charge point connected: %s", chargePoint.ID())
 
 		// trigger initial connection if charge point is already setup
-		if cp != nil {
+		if cp := reg.cp; cp != nil {
 			cp.connect(true)
 		}
 
 		return
 	}
 
 	// check for configured anonymous charge point
-	cp, ok = cs.cps[""]
-	if ok && cp != nil {
+	reg, ok = cs.regs[""]
+	if ok && reg.cp != nil {
+		cp := reg.cp
 		cs.log.INFO.Printf("charge point connected, registering: %s", chargePoint.ID())
 
 		// update id
 		cp.RegisterID(chargePoint.ID())
 
-		cs.cps[chargePoint.ID()] = cp
-		delete(cs.cps, "")
+		cs.regs[chargePoint.ID()].cp = cp
+		delete(cs.regs, "")
 
 		cp.connect(true)
 
@@ -133,7 +142,7 @@ func (cs *CS) NewChargePoint(chargePoint ocpp16.ChargePointConnection) {
 
 	// register unknown charge point
 	// when charge point setup is complete, it will eventually be associated with the connected id
-	cs.cps[chargePoint.ID()] = nil
+	cs.regs[chargePoint.ID()] = new(registration)
 }
 
 // ChargePointDisconnected implements ocpp16.ChargePointConnectionHandler

charger/ocpp/cs_core.go

@@ -66,6 +66,16 @@ func (cs *CS) OnStatusNotification(id string, request *core.StatusNotificationRe
 		return cp.OnStatusNotification(request)
 	}
 
+	cs.mu.Lock()
+	defer cs.mu.Unlock()
+
+	// cache status for future cp connection
+	if reg, ok := cs.regs[id]; ok {
+		reg.mu.Lock()
+		reg.status = request
+		reg.mu.Unlock()
+	}
+
 	return new(core.StatusNotificationConfirmation), nil
 }
 

charger/ocpp/instance.go

@@ -40,8 +40,7 @@ func Instance() *CS {
 
 		instance = &CS{
 			log:           log,
-			cps:           make(map[string]*CP),
-			init:          make(map[string]*sync.Mutex),
+			regs:          make(map[string]*registration),
 			CentralSystem: cs,
 		}
 		instance.txnId.Store(time.Now().UTC().Unix())