[usage] Implement ledger control loop

components/usage/pkg/apiv1/usage.go

@@ -9,6 +9,7 @@ import (
 	"database/sql"
 	"errors"
 	"fmt"
+	"github.com/google/uuid"
 	"math"
 	"time"
 
@@ -26,7 +27,9 @@ import (
 var _ v1.UsageServiceServer = (*UsageService)(nil)
 
 type UsageService struct {
-	conn *gorm.DB
+	conn    *gorm.DB
+	nowFunc func() time.Time
+	pricer  *WorkspacePricer
 
 	contentService contentservice.Interface
 
@@ -193,19 +196,24 @@ func (s *UsageService) ReconcileUsageWithLedger(ctx context.Context, req *v1.Rec
 		return nil, status.Errorf(codes.InvalidArgument, "To must not be before From")
 	}
 
+	now := s.nowFunc()
+
+	var instances []db.WorkspaceInstanceForUsage
 	stopped, err := db.FindStoppedWorkspaceInstancesInRange(ctx, s.conn, from, to)
 	if err != nil {
 		logger.WithError(err).Errorf("Failed to find stopped workspace instances.")
 		return nil, status.Errorf(codes.Internal, "failed to query for stopped instances")
 	}
 	logger.Infof("Found %d stopped workspace instances in range.", len(stopped))
+	instances = append(instances, stopped...)
 
 	running, err := db.FindRunningWorkspaceInstances(ctx, s.conn)
 	if err != nil {
 		logger.WithError(err).Errorf("Failed to find running workspace instances.")
 		return nil, status.Errorf(codes.Internal, "failed to query for running instances")
 	}
 	logger.Infof("Found %d running workspaces since the beginning of time.", len(running))
+	instances = append(instances, running...)
 
 	usageDrafts, err := db.FindAllDraftUsage(ctx, s.conn)
 	if err != nil {
@@ -214,12 +222,99 @@ func (s *UsageService) ReconcileUsageWithLedger(ctx context.Context, req *v1.Rec
 	}
 	logger.Infof("Found %d draft usage records.", len(usageDrafts))
 
+	instancesWithUsageInDraft, err := db.FindWorkspaceInstancesByIds(ctx, s.conn, collectWorkspaceInstanceIDs(usageDrafts))
+	if err != nil {
+		logger.WithError(err).Errorf("Failed to find workspace instances for usage records in draft.")
+		return nil, status.Errorf(codes.Internal, "failed to find workspace instances for usage records in draft state")
+	}
+	logger.Infof("Found %d workspaces instances for usage records in draft.", len(instancesWithUsageInDraft))
+	instances = append(instances, instancesWithUsageInDraft...)
+
+	inserts, updates := reconcileUsageWithLedger(instances, usageDrafts, s.pricer, now)
+	logger.WithField("inserts", inserts).WithField("updates", updates).Infof("Identified %d inserts and %d updates against usage records.", len(inserts), len(updates))
+
 	return &v1.ReconcileUsageWithLedgerResponse{}, nil
 }
 
-func NewUsageService(conn *gorm.DB, reportGenerator *ReportGenerator, contentSvc contentservice.Interface) *UsageService {
+func reconcileUsageWithLedger(instances []db.WorkspaceInstanceForUsage, drafts []db.Usage, pricer *WorkspacePricer, now time.Time) (inserts []db.Usage, updates []db.Usage) {
+
+	instancesByID := dedupeWorkspaceInstancesForUsage(instances)
+
+	draftsByWorkspaceID := map[uuid.UUID]db.Usage{}
+	for _, draft := range drafts {
+		draftsByWorkspaceID[draft.WorkspaceInstanceID] = draft
+	}
+
+	for instanceID, instance := range instancesByID {
+		if usage, exists := draftsByWorkspaceID[instanceID]; exists {
+			updates = append(updates, updateUsageFromInstance(instance, usage, pricer, now))
+			continue
+		}
+
+		inserts = append(inserts, newUsageFromInstance(instance, pricer, now))
+	}
+
+	return inserts, updates
+}
+
+const usageDescriptionFromController = "Usage collected by automated system."
+
+func newUsageFromInstance(instance db.WorkspaceInstanceForUsage, pricer *WorkspacePricer, now time.Time) db.Usage {
+	draft := true
+	if instance.StoppingTime.IsSet() {
+		draft = false
+	}
+
+	effectiveTime := now
+	if instance.StoppingTime.IsSet() {
+		effectiveTime = instance.StoppingTime.Time()
+	}
+
+	return db.Usage{
+		ID:                  uuid.New(),
+		AttributionID:       instance.UsageAttributionID,
+		Description:         usageDescriptionFromController,
+		CreditCents:         db.NewCreditCents(pricer.CreditsUsedByInstance(&instance, now)),
+		EffectiveTime:       db.NewVarcharTime(effectiveTime),
+		Kind:                db.WorkspaceInstanceUsageKind,
+		WorkspaceInstanceID: instance.ID,
+		Draft:               draft,
+		Metadata:            nil,
+	}
+}
+
+func updateUsageFromInstance(instance db.WorkspaceInstanceForUsage, usage db.Usage, pricer *WorkspacePricer, now time.Time) db.Usage {
+	// We construct a new record to ensure we always take the data from the source of truth - the workspace instance
+	updated := newUsageFromInstance(instance, pricer, now)
+	// but we override the ID to the one we already have
+	updated.ID = usage.ID
+
+	return updated
+}
+
+func collectWorkspaceInstanceIDs(usage []db.Usage) []uuid.UUID {
+	var ids []uuid.UUID
+	for _, u := range usage {
+		ids = append(ids, u.WorkspaceInstanceID)
+	}
+	return ids
+}
+
+func dedupeWorkspaceInstancesForUsage(instances []db.WorkspaceInstanceForUsage) map[uuid.UUID]db.WorkspaceInstanceForUsage {
+	set := map[uuid.UUID]db.WorkspaceInstanceForUsage{}
+	for _, instance := range instances {
+		set[instance.ID] = instance
+	}
+	return set
+}
+
+func NewUsageService(conn *gorm.DB, reportGenerator *ReportGenerator, contentSvc contentservice.Interface, pricer *WorkspacePricer) *UsageService {
 	return &UsageService{
-		conn:            conn,
+		conn: conn,
+		nowFunc: func() time.Time {
+			return time.Now().UTC()
+		},
+		pricer:          pricer,
 		reportGenerator: reportGenerator,
 		contentService:  contentSvc,
 	}

components/usage/pkg/apiv1/usage_test.go

@@ -144,7 +144,7 @@ func TestUsageService_ListBilledUsage(t *testing.T) {
 			)
 
 			generator := NewReportGenerator(dbconn, DefaultWorkspacePricer)
-			v1.RegisterUsageServiceServer(srv.GRPC(), NewUsageService(dbconn, generator, nil))
+			v1.RegisterUsageServiceServer(srv.GRPC(), NewUsageService(dbconn, generator, nil, DefaultWorkspacePricer))
 			baseserver.StartServerForTests(t, srv)
 
 			conn, err := grpc.Dial(srv.GRPCAddress(), grpc.WithTransportCredentials(insecure.NewCredentials()))
@@ -275,7 +275,7 @@ func TestUsageService_ListBilledUsage_Pagination(t *testing.T) {
 			)
 
 			generator := NewReportGenerator(dbconn, DefaultWorkspacePricer)
-			v1.RegisterUsageServiceServer(srv.GRPC(), NewUsageService(dbconn, generator, nil))
+			v1.RegisterUsageServiceServer(srv.GRPC(), NewUsageService(dbconn, generator, nil, DefaultWorkspacePricer))
 			baseserver.StartServerForTests(t, srv)
 
 			conn, err := grpc.Dial(srv.GRPCAddress(), grpc.WithTransportCredentials(insecure.NewCredentials()))
@@ -580,7 +580,7 @@ func TestUsageService_ReconcileUsageWithLedger(t *testing.T) {
 		baseserver.WithGRPC(baseserver.MustUseRandomLocalAddress(t)),
 	)
 
-	v1.RegisterUsageServiceServer(srv.GRPC(), NewUsageService(dbconn, nil, nil))
+	v1.RegisterUsageServiceServer(srv.GRPC(), NewUsageService(dbconn, nil, nil, DefaultWorkspacePricer))
 	baseserver.StartServerForTests(t, srv)
 
 	conn, err := grpc.Dial(srv.GRPCAddress(), grpc.WithTransportCredentials(insecure.NewCredentials()))
@@ -594,3 +594,105 @@ func TestUsageService_ReconcileUsageWithLedger(t *testing.T) {
 	})
 	require.NoError(t, err)
 }
+
+func TestReconcileWithLedger(t *testing.T) {
+	now := time.Date(2022, 9, 1, 10, 0, 0, 0, time.UTC)
+	pricer, err := NewWorkspacePricer(map[string]float64{
+		"default":              0.1666666667,
+		"g1-standard":          0.1666666667,
+		"g1-standard-pvc":      0.1666666667,
+		"g1-large":             0.3333333333,
+		"g1-large-pvc":         0.3333333333,
+		"gitpodio-internal-xl": 0.3333333333,
+	})
+	require.NoError(t, err)
+
+	t.Run("no action with no instances and no drafts", func(t *testing.T) {
+		inserts, updates := reconcileUsageWithLedger(nil, nil, pricer, now)
+		require.Len(t, inserts, 0)
+		require.Len(t, updates, 0)
+	})
+
+	t.Run("no action with no instances but existing drafts", func(t *testing.T) {
+		drafts := []db.Usage{dbtest.NewUsage(t, db.Usage{})}
+		inserts, updates := reconcileUsageWithLedger(nil, drafts, pricer, now)
+		require.Len(t, inserts, 0)
+		require.Len(t, updates, 0)
+	})
+
+	t.Run("creates a new usage record when no draft exists, removing duplicates", func(t *testing.T) {
+		instance := db.WorkspaceInstanceForUsage{
+			ID:          uuid.New(),
+			WorkspaceID: dbtest.GenerateWorkspaceID(),
+			OwnerID:     uuid.New(),
+			ProjectID: sql.NullString{
+				String: "my-project",
+				Valid:  true,
+			},
+			WorkspaceClass:     db.WorkspaceClass_Default,
+			Type:               db.WorkspaceType_Regular,
+			UsageAttributionID: db.NewTeamAttributionID(uuid.New().String()),
+			CreationTime:       db.NewVarcharTime(now.Add(1 * time.Minute)),
+		}
+
+		inserts, updates := reconcileUsageWithLedger([]db.WorkspaceInstanceForUsage{instance, instance}, nil, pricer, now)
+		require.Len(t, inserts, 1)
+		require.Len(t, updates, 0)
+		require.Equal(t, db.Usage{
+			ID:                  inserts[0].ID,
+			AttributionID:       instance.UsageAttributionID,
+			Description:         usageDescriptionFromController,
+			CreditCents:         db.NewCreditCents(pricer.CreditsUsedByInstance(&instance, now)),
+			EffectiveTime:       db.NewVarcharTime(now),
+			Kind:                db.WorkspaceInstanceUsageKind,
+			WorkspaceInstanceID: instance.ID,
+			Draft:               true,
+			Metadata:            nil,
+		}, inserts[0])
+	})
+
+	t.Run("updates a usage record when a draft exists", func(t *testing.T) {
+		instance := db.WorkspaceInstanceForUsage{
+			ID:          uuid.New(),
+			WorkspaceID: dbtest.GenerateWorkspaceID(),
+			OwnerID:     uuid.New(),
+			ProjectID: sql.NullString{
+				String: "my-project",
+				Valid:  true,
+			},
+			WorkspaceClass:     db.WorkspaceClass_Default,
+			Type:               db.WorkspaceType_Regular,
+			UsageAttributionID: db.NewTeamAttributionID(uuid.New().String()),
+			CreationTime:       db.NewVarcharTime(now.Add(1 * time.Minute)),
+		}
+
+		// the fields in the usage record deliberately do not match the instance, except for the Instance ID.
+		// we do this to test that the fields in the usage records get updated to reflect the true values from the source of truth - instances.
+		draft := dbtest.NewUsage(t, db.Usage{
+			ID:                  uuid.New(),
+			AttributionID:       db.NewUserAttributionID(uuid.New().String()),
+			Description:         "Some description",
+			CreditCents:         1,
+			EffectiveTime:       db.VarcharTime{},
+			Kind:                db.WorkspaceInstanceUsageKind,
+			WorkspaceInstanceID: instance.ID,
+			Draft:               true,
+			Metadata:            nil,
+		})
+
+		inserts, updates := reconcileUsageWithLedger([]db.WorkspaceInstanceForUsage{instance}, []db.Usage{draft}, pricer, now)
+		require.Len(t, inserts, 0)
+		require.Len(t, updates, 1)
+		require.Equal(t, db.Usage{
+			ID:                  draft.ID,
+			AttributionID:       instance.UsageAttributionID,
+			Description:         usageDescriptionFromController,
+			CreditCents:         db.NewCreditCents(pricer.CreditsUsedByInstance(&instance, now)),
+			EffectiveTime:       db.NewVarcharTime(now),
+			Kind:                db.WorkspaceInstanceUsageKind,
+			WorkspaceInstanceID: instance.ID,
+			Draft:               true,
+			Metadata:            nil,
+		}, updates[0])
+	})
+}

components/usage/pkg/db/usage.go

@@ -7,6 +7,7 @@ package db
 import (
 	"context"
 	"fmt"
+	"math"
 
 	"github.com/google/uuid"
 	"gorm.io/datatypes"
@@ -21,11 +22,22 @@ const (
 	InvoiceUsageKind                     = "invoice"
 )
 
+func NewCreditCents(n float64) CreditCents {
+	inCents := n * 100
+	return CreditCents(int64(math.Round(inCents)))
+}
+
+type CreditCents int64
+
+func (cc CreditCents) ToCredits() float64 {
+	return float64(cc) / 100
+}
+
 type Usage struct {
 	ID                  uuid.UUID      `gorm:"primary_key;column:id;type:char;size:36;" json:"id"`
 	AttributionID       AttributionID  `gorm:"column:attributionId;type:varchar;size:255;" json:"attributionId"`
 	Description         string         `gorm:"column:description;type:varchar;size:255;" json:"description"`
-	CreditCents         int64          `gorm:"column:creditCents;type:bigint;" json:"creditCents"`
+	CreditCents         CreditCents    `gorm:"column:creditCents;type:bigint;" json:"creditCents"`
 	EffectiveTime       VarcharTime    `gorm:"column:effectiveTime;type:varchar;size:255;" json:"effectiveTime"`
 	Kind                UsageKind      `gorm:"column:kind;type:char;size:10;" json:"kind"`
 	WorkspaceInstanceID uuid.UUID      `gorm:"column:workspaceInstanceId;type:char;size:36;" json:"workspaceInstanceId"`

components/usage/pkg/db/usage_test.go

@@ -137,3 +137,61 @@ func TestFindAllDraftUsage(t *testing.T) {
 		require.True(t, usage.Draft)
 	}
 }
+
+func TestCreditCents(t *testing.T) {
+	for _, s := range []struct {
+		value           float64
+		expected        db.CreditCents
+		expectedAsFloat float64
+	}{
+		{
+			value:           0,
+			expected:        0,
+			expectedAsFloat: 0,
+		},
+		{
+			value:           0.1,
+			expected:        10,
+			expectedAsFloat: 0.1,
+		},
+		{
+			value:           1.1111,
+			expected:        111,
+			expectedAsFloat: 1.11,
+		},
+		{
+			value:           1.4999,
+			expected:        150,
+			expectedAsFloat: 1.50,
+		},
+		{
+			value:           1.500,
+			expected:        150,
+			expectedAsFloat: 1.50,
+		},
+		{
+			value:           1.501,
+			expected:        150,
+			expectedAsFloat: 1.50,
+		},
+		{
+			value:           1.50999,
+			expected:        151,
+			expectedAsFloat: 1.51,
+		},
+		{
+			value:           1.9999,
+			expected:        200,
+			expectedAsFloat: 2.00,
+		},
+		{
+			value:           -1.9999,
+			expected:        -200,
+			expectedAsFloat: -2.00,
+		},
+	} {
+		cc := db.NewCreditCents(s.value)
+		require.Equal(t, s.expected, cc)
+		require.Equal(t, s.expectedAsFloat, cc.ToCredits())
+	}
+}

components/usage/pkg/server/server.go

@@ -157,7 +157,7 @@ func Start(cfg Config) error {
 
 	reportGenerator := apiv1.NewReportGenerator(conn, pricer)
 
-	err = registerGRPCServices(srv, conn, stripeClient, reportGenerator, contentService, *cfg.BillInstancesAfter)
+	err = registerGRPCServices(srv, conn, stripeClient, reportGenerator, contentService, pricer, *cfg.BillInstancesAfter)
 	if err != nil {
 		return fmt.Errorf("failed to register gRPC services: %w", err)
 	}
@@ -180,8 +180,8 @@ func Start(cfg Config) error {
 	return nil
 }
 
-func registerGRPCServices(srv *baseserver.Server, conn *gorm.DB, stripeClient *stripe.Client, reportGenerator *apiv1.ReportGenerator, contentSvc contentservice.Interface, billInstancesAfter time.Time) error {
-	v1.RegisterUsageServiceServer(srv.GRPC(), apiv1.NewUsageService(conn, reportGenerator, contentSvc))
+func registerGRPCServices(srv *baseserver.Server, conn *gorm.DB, stripeClient *stripe.Client, reportGenerator *apiv1.ReportGenerator, contentSvc contentservice.Interface, pricer *apiv1.WorkspacePricer, billInstancesAfter time.Time) error {
+	v1.RegisterUsageServiceServer(srv.GRPC(), apiv1.NewUsageService(conn, reportGenerator, contentSvc, pricer))
 	if stripeClient == nil {
 		v1.RegisterBillingServiceServer(srv.GRPC(), &apiv1.BillingServiceNoop{})
 	} else {