Restore SelectCertificateStatuses to SA. (#4902)

And use it in ocsp-updater. This was cleaned up in #4546 because it was
unused, but it should have been in use in ocsp-updater now that we can
make a straightforward query here instead of a JOIN.

This makes the SA the single source of truth for what columns are in the
certificateStatus table.

cmd/ocsp-updater/main.go

@@ -142,21 +142,12 @@ func newUpdater(
 }
 
 func (updater *OCSPUpdater) findStaleOCSPResponses(oldestLastUpdatedTime time.Time, batchSize int) ([]core.CertificateStatus, error) {
-	var statuses []core.CertificateStatus
-
-	certStatusFields := "cs.serial, cs.status, cs.revokedDate, cs.notAfter, cs.revokedReason"
-	if features.Enabled(features.StoreIssuerInfo) {
-		certStatusFields += ", cs.issuerID"
-	}
-	_, err := updater.dbMap.Select(
-		&statuses,
-		fmt.Sprintf(`SELECT
-				%s
-				FROM certificateStatus AS cs
-				WHERE cs.ocspLastUpdated < :lastUpdate
-				AND NOT cs.isExpired
-				ORDER BY cs.ocspLastUpdated ASC
-				LIMIT :limit`, certStatusFields),
+	statuses, err := sa.SelectCertificateStatuses(
+		updater.dbMap,
+		`WHERE ocspLastUpdated < :lastUpdate
+		 AND NOT isExpired
+		 ORDER BY ocspLastUpdated ASC
+		 LIMIT :limit`,
 		map[string]interface{}{
 			"lastUpdate": oldestLastUpdatedTime,
 			"limit":      batchSize,

sa/model.go

@@ -113,19 +113,34 @@ func certStatusFields() []string {
 	return []string{"serial", "status", "ocspLastUpdated", "revokedDate", "revokedReason", "lastExpirationNagSent", "ocspResponse", "notAfter", "isExpired", "issuerID"}
 }
 
+func certStatusFieldsSelect(restOfQuery string) string {
+	fields := strings.Join(certStatusFields(), ",")
+	return fmt.Sprintf("SELECT %s FROM certificateStatus %s", fields, restOfQuery)
+}
+
 // SelectCertificateStatus selects all fields of one certificate status model
 func SelectCertificateStatus(s db.OneSelector, q string, args ...interface{}) (certStatusModel, error) {
 	var model certStatusModel
-	fields := strings.Join(certStatusFields(), ",")
 	err := s.SelectOne(
 		&model,
-		`SELECT `+fields+
-			` FROM certificateStatus `+q,
+		certStatusFieldsSelect(q),
 		args...,
 	)
 	return model, err
 }
 
+// SelectCertificateStatuses selects all fields of multiple certificate status
+// objects
+func SelectCertificateStatuses(s db.Selector, q string, args ...interface{}) ([]core.CertificateStatus, error) {
+	var models []core.CertificateStatus
+	_, err := s.Select(
+		&models,
+		certStatusFieldsSelect(q),
+		args...,
+	)
+	return models, err
+}
+
 var mediumBlobSize = int(math.Pow(2, 24))
 
 type issuedNameModel struct {