challenger: configurable invoice query batch size with sane default

aperture.go

@@ -336,7 +336,8 @@ func (a *Aperture) Start(errChan chan error) error {
 			}
 
 			a.challenger, err = challenger.NewLNCChallenger(
-				session, lncStore, genInvoiceReq, errChan,
+				session, lncStore, a.cfg.InvoiceBatchSize,
+				genInvoiceReq, errChan,
 			)
 			if err != nil {
 				return fmt.Errorf("unable to start lnc "+
@@ -359,8 +360,8 @@ func (a *Aperture) Start(errChan chan error) error {
 			}
 
 			a.challenger, err = challenger.NewLndChallenger(
-				client, genInvoiceReq, context.Background,
-				errChan,
+				client, a.cfg.InvoiceBatchSize, genInvoiceReq,
+				context.Background, errChan,
 			)
 			if err != nil {
 				return err

challenger/lnc.go

@@ -19,7 +19,7 @@ type LNCChallenger struct {
 // NewLNCChallenger creates a new challenger that uses the given LNC session to
 // connect to an lnd backend to create payment challenges.
 func NewLNCChallenger(session *lnc.Session, lncStore lnc.Store,
-	genInvoiceReq InvoiceRequestGenerator,
+	invoiceBatchSize int, genInvoiceReq InvoiceRequestGenerator,
 	errChan chan<- error) (*LNCChallenger, error) {
 
 	nodeConn, err := lnc.NewNodeConn(session, lncStore)
@@ -34,7 +34,8 @@ func NewLNCChallenger(session *lnc.Session, lncStore lnc.Store,
 	}
 
 	lndChallenger, err := NewLndChallenger(
-		client, genInvoiceReq, nodeConn.CtxFunc, errChan,
+		client, invoiceBatchSize, genInvoiceReq, nodeConn.CtxFunc,
+		errChan,
 	)
 	if err != nil {
 		return nil, err

challenger/lnd.go

@@ -12,16 +12,11 @@ import (
 	"github.com/lightningnetwork/lnd/lntypes"
 )
 
-const (
-	// invoiceQueryPageSize is the maximum number of invoices that will be
-	// queried in a single request.
-	invoiceQueryPageSize = 1000
-)
-
 // LndChallenger is a challenger that uses an lnd backend to create new L402
 // payment challenges.
 type LndChallenger struct {
 	client        InvoiceClient
+	batchSize     int
 	clientCtx     func() context.Context
 	genInvoiceReq InvoiceRequestGenerator
 
@@ -42,7 +37,7 @@ var _ Challenger = (*LndChallenger)(nil)
 
 // NewLndChallenger creates a new challenger that uses the given connection to
 // an lnd backend to create payment challenges.
-func NewLndChallenger(client InvoiceClient,
+func NewLndChallenger(client InvoiceClient, batchSize int,
 	genInvoiceReq InvoiceRequestGenerator,
 	ctxFunc func() context.Context,
 	errChan chan<- error) (*LndChallenger, error) {
@@ -60,6 +55,7 @@ func NewLndChallenger(client InvoiceClient,
 	invoicesMtx := &sync.Mutex{}
 	challenger := &LndChallenger{
 		client:        client,
+		batchSize:     batchSize,
 		clientCtx:     ctxFunc,
 		genInvoiceReq: genInvoiceReq,
 		invoiceStates: make(map[lntypes.Hash]lnrpc.Invoice_InvoiceState),
@@ -100,7 +96,7 @@ func (l *LndChallenger) Start() error {
 		invoiceResp, err := l.client.ListInvoices(
 			ctx, &lnrpc.ListInvoiceRequest{
 				IndexOffset:    indexOffset,
-				NumMaxInvoices: invoiceQueryPageSize,
+				NumMaxInvoices: uint64(l.batchSize),
 			},
 		)
 		if err != nil {

challenger/lnd_test.go

@@ -112,6 +112,7 @@ func newChallenger() (*LndChallenger, *mockInvoiceClient, chan error) {
 	mainErrChan := make(chan error)
 	return &LndChallenger{
 		client:        mockClient,
+		batchSize:     1,
 		clientCtx:     context.Background,
 		genInvoiceReq: genInvoiceReq,
 		invoiceStates: make(map[lntypes.Hash]lnrpc.Invoice_InvoiceState),
@@ -141,7 +142,7 @@ func TestLndChallenger(t *testing.T) {
 	// First of all, test that the NewLndChallenger doesn't allow a nil
 	// invoice generator function.
 	errChan := make(chan error)
-	_, err := NewLndChallenger(nil, nil, nil, errChan)
+	_, err := NewLndChallenger(nil, 1, nil, nil, errChan)
 	require.Error(t, err)
 
 	// Now mock the lnd backend and create a challenger instance that we can

config.go

@@ -12,14 +12,15 @@ import (
 )
 
 var (
-	apertureDataDir        = btcutil.AppDataDir("aperture", false)
-	defaultConfigFilename  = "aperture.yaml"
-	defaultTLSKeyFilename  = "tls.key"
-	defaultTLSCertFilename = "tls.cert"
-	defaultLogLevel        = "info"
-	defaultLogFilename     = "aperture.log"
-	defaultMaxLogFiles     = 3
-	defaultMaxLogFileSize  = 10
+	apertureDataDir         = btcutil.AppDataDir("aperture", false)
+	defaultConfigFilename   = "aperture.yaml"
+	defaultTLSKeyFilename   = "tls.key"
+	defaultTLSCertFilename  = "tls.cert"
+	defaultLogLevel         = "info"
+	defaultLogFilename      = "aperture.log"
+	defaultMaxLogFiles      = 3
+	defaultMaxLogFileSize   = 10
+	defaultInvoiceBatchSize = 100000
 
 	defaultSqliteDatabaseFileName = "aperture.db"
 
@@ -219,6 +220,10 @@ type Config struct {
 	// WriteTimeout is the maximum amount of time to wait for a response to
 	// be fully written.
 	WriteTimeout time.Duration `long:"writetimeout" description:"The maximum amount of time to wait for a response to be fully written."`
+
+	// InvoiceBatchSize is the number of invoices to fetch in a single
+	// request.
+	InvoiceBatchSize int `long:"invoicebatchsize" description:"The number of invoices to fetch in a single request."`
 }
 
 func (c *Config) validate() error {
@@ -232,6 +237,10 @@ func (c *Config) validate() error {
 		return fmt.Errorf("missing listen address for server")
 	}
 
+	if c.InvoiceBatchSize <= 0 {
+		return fmt.Errorf("invoice batch size must be greater than 0")
+	}
+
 	return nil
 }
 
@@ -246,16 +255,17 @@ func DefaultSqliteConfig() *aperturedb.SqliteConfig {
 // NewConfig initializes a new Config variable.
 func NewConfig() *Config {
 	return &Config{
-		DatabaseBackend: "etcd",
-		Etcd:            &EtcdConfig{},
-		Sqlite:          DefaultSqliteConfig(),
-		Postgres:        &aperturedb.PostgresConfig{},
-		Authenticator:   &AuthConfig{},
-		Tor:             &TorConfig{},
-		HashMail:        &HashMailConfig{},
-		Prometheus:      &PrometheusConfig{},
-		IdleTimeout:     defaultIdleTimeout,
-		ReadTimeout:     defaultReadTimeout,
-		WriteTimeout:    defaultWriteTimeout,
+		DatabaseBackend:  "etcd",
+		Etcd:             &EtcdConfig{},
+		Sqlite:           DefaultSqliteConfig(),
+		Postgres:         &aperturedb.PostgresConfig{},
+		Authenticator:    &AuthConfig{},
+		Tor:              &TorConfig{},
+		HashMail:         &HashMailConfig{},
+		Prometheus:       &PrometheusConfig{},
+		IdleTimeout:      defaultIdleTimeout,
+		ReadTimeout:      defaultReadTimeout,
+		WriteTimeout:     defaultWriteTimeout,
+		InvoiceBatchSize: defaultInvoiceBatchSize,
 	}
 }