invoices: add subscription to invoice updates

This commit adds the ability for clients within the daemon to register
for notifications that are dispatched once invoices are settled, or new
invoices are added. Such notifications can prove useful when
synchronizing higher level primitives, or implementing workflow within
desktop/mobile UI’s.
This commit is contained in:
Olaoluwa Osuntokun 2016-10-14 19:47:10 -07:00
parent 3247a160c5
commit cfd9f8f6f0
No known key found for this signature in database
GPG Key ID: 9CC5B105D03521A2

@ -31,6 +31,10 @@ type invoiceRegistry struct {
cdb *channeldb.DB cdb *channeldb.DB
clientMtx sync.Mutex
nextClientID uint32
notificationClients map[uint32]*invoiceSubscription
// debugInvoices is a mp which stores special "debug" invoices which // debugInvoices is a mp which stores special "debug" invoices which
// should be only created/used when manual tests require an invoice // should be only created/used when manual tests require an invoice
// that *all* nodes are able to fully settle. // that *all* nodes are able to fully settle.
@ -43,8 +47,9 @@ type invoiceRegistry struct {
// which are volatile yet available system wide within the daemon. // which are volatile yet available system wide within the daemon.
func newInvoiceRegistry(cdb *channeldb.DB) *invoiceRegistry { func newInvoiceRegistry(cdb *channeldb.DB) *invoiceRegistry {
return &invoiceRegistry{ return &invoiceRegistry{
cdb: cdb, cdb: cdb,
debugInvoices: make(map[wire.ShaHash]*channeldb.Invoice), debugInvoices: make(map[wire.ShaHash]*channeldb.Invoice),
notificationClients: make(map[uint32]*invoiceSubscription),
} }
} }
@ -83,7 +88,14 @@ func (i *invoiceRegistry) AddInvoice(invoice *channeldb.Invoice) error {
})) }))
// TODO(roasbeef): also check in memory for quick lookups/settles? // TODO(roasbeef): also check in memory for quick lookups/settles?
return i.cdb.AddInvoice(invoice) if err := i.cdb.AddInvoice(invoice); err != nil {
return err
}
// TODO(roasbeef): re-enable?
//go i.notifyClients(invoice, false)
return nil
} }
// lookupInvoice looks up an invoice by it's payment hash (R-Hash), if found // lookupInvoice looks up an invoice by it's payment hash (R-Hash), if found
@ -126,5 +138,80 @@ func (i *invoiceRegistry) SettleInvoice(rHash wire.ShaHash) error {
// If this isn't a debug invoice, then we'll attempt to settle an // If this isn't a debug invoice, then we'll attempt to settle an
// invoice matching this rHash on disk (if one exists). // invoice matching this rHash on disk (if one exists).
return i.cdb.SettleInvoice(rHash) if err := i.cdb.SettleInvoice(rHash); err != nil {
return err
}
// Launch a new goroutine to notify any/all registered invoice
// notification clients.
go func() {
invoice, err := i.cdb.LookupInvoice(rHash)
if err != nil {
ltndLog.Errorf("unable to find invoice: %v", err)
return
}
i.notifyClients(invoice, true)
}()
return nil
}
// notifyClients notifies all currently registered invoice notificaiton clients
// of a newly added/settled invoice.
func (i *invoiceRegistry) notifyClients(invoice *channeldb.Invoice, settle bool) {
i.clientMtx.Lock()
defer i.clientMtx.Unlock()
for _, client := range i.notificationClients {
var eventChan chan *channeldb.Invoice
if settle {
eventChan = client.SettledInvoices
} else {
eventChan = client.NewInvoices
}
go func() {
eventChan <- invoice
}()
}
}
// invoiceSubscription represents an intent to receive updates for newly added
// or settled invoices. For each newly added invoice, a copy of the invoice
// will be sent over the NewInvoices channel. Similarly, for each newly settled
// invoice, a copy of the invoice will be sent over the SettledInvoices
// channel.
type invoiceSubscription struct {
NewInvoices chan *channeldb.Invoice
SettledInvoices chan *channeldb.Invoice
inv *invoiceRegistry
id uint32
}
// Cancel unregisteres the invoiceSubscription, freeing any previoulsy allocate
// resources.
func (i *invoiceSubscription) Cancel() {
i.inv.clientMtx.Lock()
delete(i.inv.notificationClients, i.id)
i.inv.clientMtx.Unlock()
}
// SubscribeNotifications returns an invoiceSubscription which allows the
// caller to receive async notifications when any invoices are settled or
// added.
func (i *invoiceRegistry) SubscribeNotifications() *invoiceSubscription {
client := &invoiceSubscription{
NewInvoices: make(chan *channeldb.Invoice),
SettledInvoices: make(chan *channeldb.Invoice),
}
i.clientMtx.Lock()
i.notificationClients[i.nextClientID] = client
client.id = i.nextClientID
i.nextClientID++
i.clientMtx.Unlock()
return client
} }