Set up default currency accounts automatically (#72)

backend/product/payments/accounts.go

@@ -0,0 +1,50 @@
+package payments
+
+import (
+	"context"
+	"time"
+
+	customer "git.sendico.io/tech/sxchnge/product/customers/model"
+	merrors "git.sendico.io/tech/sxchnge/shared/errors"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promauto"
+	"go.uber.org/zap"
+)
+
+var accountSetup = promauto.NewCounterVec(prometheus.CounterOpts{Name: "sxchnge_currency_accounts_setup_total", Help: "Default currency account setup attempts, including checks of existing accounts."}, []string{"outcome"})
+var accountSetupDuration = promauto.NewHistogram(prometheus.HistogramOpts{Name: "sxchnge_currency_accounts_setup_duration_seconds", Help: "Time to confirm all default currency accounts exist."})
+
+func (s *Service) Ensure(ctx context.Context, a *customer.Account) error {
+	_, err := s.ensureAccounts(ctx, a)
+	if err != nil {
+		return merrors.ServiceUnavailableWrap(err, "currency account setup unavailable")
+	}
+	return nil
+}
+
+func (s *Service) ensureAccounts(ctx context.Context, a *customer.Account) (subject string, result error) {
+	started := time.Now()
+	defer func() {
+		outcome := "ready"
+		if result != nil {
+			outcome = "failed"
+		}
+		accountSetup.WithLabelValues(outcome).Inc()
+		accountSetupDuration.Observe(time.Since(started).Seconds())
+	}()
+	if s == nil || s.Identity == nil || s.Provider == nil {
+		return "", Unavailable
+	}
+	if a == nil || a.ID.IsZero() {
+		return "", NotFound
+	}
+	subject, result = s.Identity.Subject(ctx, a)
+	if result != nil {
+		return "", result
+	}
+	if result = s.Provider.EnsureAccounts(ctx, subject); result != nil {
+		s.Logger.Warn("Currency account setup incomplete", zap.String("account_ref", a.ID.Hex()), zap.Error(result))
+		return "", result
+	}
+	return subject, nil
+}

backend/product/payments/accounts_test.go

@@ -0,0 +1,28 @@
+package payments
+
+import (
+	"testing"
+
+	customer "git.sendico.io/tech/sxchnge/product/customers/model"
+	"github.com/stretchr/testify/require"
+	"go.mongodb.org/mongo-driver/v2/bson"
+	"go.uber.org/zap"
+)
+
+func TestSignupAndWalletReadEnsureCustomerCurrencyAccounts(t *testing.T) {
+	a := &customer.Account{}
+	a.ID = bson.NewObjectID()
+	p := &provider{namespace: "provider"}
+	s := &Service{Provider: p, Identity: identity{}, Logger: zap.NewNop(), Factors: &factors{}, Store: &memoryStore{records: map[bson.ObjectID]Record{}}}
+	require.NoError(t, s.Ensure(t.Context(), a))
+	require.Equal(t, "subject", p.setupSubject)
+	snapshot, err := s.Fetch(t.Context(), a)
+	require.NoError(t, err)
+	require.Len(t, snapshot.Accounts, 1)
+	require.Equal(t, 2, p.setupCalls)
+	p.setupErr = Unavailable
+	_, err = s.Fetch(t.Context(), a)
+	require.ErrorIs(t, err, Unavailable)
+	require.Error(t, s.Ensure(t.Context(), a))
+	require.Error(t, s.Ensure(t.Context(), nil))
+}

backend/product/payments/model.go

@@ -53,6 +53,7 @@ func (*Record) Collection() string { return "payment_quotes" }
 
 type Provider interface {
 	Namespace() string
+	EnsureAccounts(context.Context, string) error
 	Accounts(context.Context, string) ([]Account, error)
 	Quote(context.Context, string, Request, []Account) (Quote, error)
 	Execute(context.Context, string, string) (RemoteOperation, error)

backend/product/payments/service.go

@@ -206,7 +206,7 @@ func (s *Service) Fetch(ctx context.Context, a *customer.Account) (Snapshot, err
 	if err := s.ready(); err != nil {
 		return Snapshot{}, err
 	}
-	subject, err := s.Identity.Subject(ctx, a)
+	subject, err := s.ensureAccounts(ctx, a)
 	if err != nil {
 		return Snapshot{}, err
 	}

backend/product/payments/service_test.go

@@ -76,15 +76,25 @@ func (s *memoryStore) Attach(_ context.Context, r *Record, id string) error {
 }
 
 type provider struct {
-	mu        sync.Mutex
-	accepted  int
-	lost      bool
-	status    string
-	key       string
-	namespace string
+	mu           sync.Mutex
+	accepted     int
+	lost         bool
+	status       string
+	key          string
+	namespace    string
+	setupCalls   int
+	setupSubject string
+	setupErr     error
 }
 
 func (p *provider) Namespace() string { return p.namespace }
+func (p *provider) EnsureAccounts(_ context.Context, subject string) error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	p.setupCalls++
+	p.setupSubject = subject
+	return p.setupErr
+}
 func (p *provider) Accounts(context.Context, string) ([]Account, error) {
 	return []Account{{ID: "ledger", Currency: "EUR", Precision: 2, Available: 5000}}, nil
 }