refact(billing): Use sql functions instead of views

These functions will ensure that UTC time is used for billing queries,
eliminating the need for the repository to set the timezone. This also
means the repository no longern needs a writer.

internal/billing/query.go

@@ -6,17 +6,14 @@ package billing
 const (
 	activeUsersLastTwoMonthsQuery = `
 select *
-  from hcp_billing_monthly_active_users_last_2_months
+  from hcp_billing_monthly_active_users_last_2_months();
 `
 	activeUsersWithStartTimeQuery = `
 select *
-  from hcp_billing_monthly_active_users_all
- where start_time >= @start_time
+  from hcp_billing_monthly_active_users_all(@start_time);
 `
 	activeUsersWithStartTimeAndEndTimeQuery = `
 select *
-  from hcp_billing_monthly_active_users_all
- where start_time >= @start_time
-   and end_time   <  @end_time
+  from hcp_billing_monthly_active_users_all(@start_time, @end_time);
 `
 )

internal/billing/repository.go

@@ -24,23 +24,19 @@ import (
 //     cumulative count up to the present date.
 type Repository struct {
 	reader db.Reader
-	writer db.Writer
 }
 
 // NewRepository creates a new Repository. The returned repository is not safe for concurrent go
 // routines to access it.
-func NewRepository(ctx context.Context, r db.Reader, w db.Writer) (*Repository, error) {
+func NewRepository(ctx context.Context, r db.Reader) (*Repository, error) {
 	const op = "billing.NewRepository"
 	switch {
 	case r == nil:
 		return nil, errors.New(ctx, errors.InvalidParameter, op, "nil db reader")
-	case w == nil:
-		return nil, errors.New(ctx, errors.InvalidParameter, op, "nil db writer")
 	}
 
 	return &Repository{
 		reader: r,
-		writer: w,
 	}, nil
 }
 
@@ -81,40 +77,30 @@ func (r *Repository) MonthlyActiveUsers(ctx context.Context, opt ...Option) ([]A
 	}
 
 	var activeUsers []ActiveUsers
-	if _, err := r.writer.DoTx(ctx, db.StdRetryCnt, db.ExpBackoff{}, func(r db.Reader, w db.Writer) error {
-		_, err := w.Exec(ctx, `set timezone to 'utc'`, nil)
-		if err != nil {
-			return err
+	rows, err := r.reader.Query(ctx, query, args)
+	if err != nil {
+		return nil, err
+	}
+	defer rows.Close()
+	if err := rows.Err(); err != nil {
+		return nil, err
+	}
+	for rows.Next() {
+		var startTime time.Time
+		var endTime time.Time
+		var count uint64
+		if err := rows.Scan(&startTime, &endTime, &count); err != nil {
+			return nil, err
 		}
 
-		rows, err := r.Query(ctx, query, args)
-		if err != nil {
-			return err
-		}
-		defer rows.Close()
-		if err := rows.Err(); err != nil {
-			return err
+		// set start and end times to be in UTC
+		auUTC := ActiveUsers{
+			ActiveUsersCount: count,
+			StartTime:        startTime.UTC(),
+			EndTime:          endTime.UTC(),
 		}
-		for rows.Next() {
-			var start_time time.Time
-			var end_time time.Time
-			var count uint64
-			if err := rows.Scan(&start_time, &end_time, &count); err != nil {
-				return err
-			}
+		activeUsers = append(activeUsers, auUTC)
 
-			// set start and end times to be in UTC
-			auUTC := ActiveUsers{
-				ActiveUsersCount: count,
-				StartTime:        start_time.UTC(),
-				EndTime:          end_time.UTC(),
-			}
-			activeUsers = append(activeUsers, auUTC)
-
-		}
-		return nil
-	}); err != nil {
-		return nil, errors.Wrap(ctx, err, op)
 	}
 
 	return activeUsers, nil

internal/billing/repository_test.go

@@ -35,39 +35,26 @@ func TestRepository_New(t *testing.T) {
 			name: "valid",
 			args: args{
 				r: rw,
-				w: rw,
 			},
 			want: &Repository{
 				reader: rw,
-				writer: rw,
 			},
 		},
 		{
 			name: "nil-reader",
 			args: args{
 				r: nil,
-				w: rw,
 			},
 			want:       nil,
 			wantIsErr:  errors.InvalidParameter,
 			wantErrMsg: "billing.NewRepository: nil db reader: parameter violation: error #100",
 		},
-		{
-			name: "nil-writer",
-			args: args{
-				r: rw,
-				w: nil,
-			},
-			want:       nil,
-			wantIsErr:  errors.InvalidParameter,
-			wantErrMsg: "billing.NewRepository: nil db writer: parameter violation: error #100",
-		},
 	}
 	for _, tt := range tests {
 		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
 			assert := assert.New(t)
-			got, err := NewRepository(context.Background(), tt.args.r, tt.args.w)
+			got, err := NewRepository(context.Background(), tt.args.r)
 			if tt.wantIsErr != 0 {
 				assert.Truef(errors.Match(errors.T(tt.wantIsErr), err), "Unexpected error %s", err)
 				assert.Equal(tt.wantErrMsg, err.Error())

internal/billing/testing.go

@@ -88,7 +88,7 @@ func TestRepo(t testing.TB, conn *db.DB) *Repository {
 	require := require.New(t)
 	rw := db.New(conn)
 
-	repo, err := NewRepository(ctx, rw, rw)
+	repo, err := NewRepository(ctx, rw)
 	require.NoError(err)
 	return repo
 }

internal/daemon/controller/controller.go

@@ -451,7 +451,7 @@ func New(ctx context.Context, conf *Config) (*Controller, error) {
 		return server.NewRepositoryStorage(ctx, dbase, dbase, c.kms)
 	}
 	c.BillingRepoFn = func() (*billing.Repository, error) {
-		return billing.NewRepository(ctx, dbase, dbase)
+		return billing.NewRepository(ctx, dbase)
 	}
 
 	// Check that credentials are available at startup, to avoid some harmless