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- package testfixtures
-
- import (
- "database/sql"
- "fmt"
- "strings"
- )
-
- // PostgreSQL is the PG helper for this package
- type PostgreSQL struct {
- baseHelper
-
- // UseAlterConstraint If true, the contraint disabling will do
- // using ALTER CONTRAINT sintax, only allowed in PG >= 9.4.
- // If false, the constraint disabling will use DISABLE TRIGGER ALL,
- // which requires SUPERUSER privileges.
- UseAlterConstraint bool
-
- tables []string
- sequences []string
- nonDeferrableConstraints []pgConstraint
- tablesChecksum map[string]string
- }
-
- type pgConstraint struct {
- tableName string
- constraintName string
- }
-
- func (h *PostgreSQL) init(db *sql.DB) error {
- var err error
-
- h.tables, err = h.tableNames(db)
- if err != nil {
- return err
- }
-
- h.sequences, err = h.getSequences(db)
- if err != nil {
- return err
- }
-
- h.nonDeferrableConstraints, err = h.getNonDeferrableConstraints(db)
- if err != nil {
- return err
- }
-
- return nil
- }
-
- func (*PostgreSQL) paramType() int {
- return paramTypeDollar
- }
-
- func (*PostgreSQL) databaseName(q queryable) (string, error) {
- var dbName string
- err := q.QueryRow("SELECT current_database()").Scan(&dbName)
- return dbName, err
- }
-
- func (h *PostgreSQL) tableNames(q queryable) ([]string, error) {
- var tables []string
-
- sql := `
- SELECT pg_namespace.nspname || '.' || pg_class.relname
- FROM pg_class
- INNER JOIN pg_namespace ON pg_namespace.oid = pg_class.relnamespace
- WHERE pg_class.relkind = 'r'
- AND pg_namespace.nspname NOT IN ('pg_catalog', 'information_schema')
- AND pg_namespace.nspname NOT LIKE 'pg_toast%';
- `
- rows, err := q.Query(sql)
- if err != nil {
- return nil, err
- }
- defer rows.Close()
-
- for rows.Next() {
- var table string
- if err = rows.Scan(&table); err != nil {
- return nil, err
- }
- tables = append(tables, table)
- }
- if err = rows.Err(); err != nil {
- return nil, err
- }
- return tables, nil
- }
-
- func (h *PostgreSQL) getSequences(q queryable) ([]string, error) {
- const sql = `
- SELECT pg_namespace.nspname || '.' || pg_class.relname AS sequence_name
- FROM pg_class
- INNER JOIN pg_namespace ON pg_namespace.oid = pg_class.relnamespace
- WHERE pg_class.relkind = 'S'
- `
-
- rows, err := q.Query(sql)
- if err != nil {
- return nil, err
- }
- defer rows.Close()
-
- var sequences []string
- for rows.Next() {
- var sequence string
- if err = rows.Scan(&sequence); err != nil {
- return nil, err
- }
- sequences = append(sequences, sequence)
- }
- if err = rows.Err(); err != nil {
- return nil, err
- }
- return sequences, nil
- }
-
- func (*PostgreSQL) getNonDeferrableConstraints(q queryable) ([]pgConstraint, error) {
- var constraints []pgConstraint
-
- sql := `
- SELECT table_schema || '.' || table_name, constraint_name
- FROM information_schema.table_constraints
- WHERE constraint_type = 'FOREIGN KEY'
- AND is_deferrable = 'NO'
- `
- rows, err := q.Query(sql)
- if err != nil {
- return nil, err
- }
-
- defer rows.Close()
- for rows.Next() {
- var constraint pgConstraint
- if err = rows.Scan(&constraint.tableName, &constraint.constraintName); err != nil {
- return nil, err
- }
- constraints = append(constraints, constraint)
- }
- if err = rows.Err(); err != nil {
- return nil, err
- }
- return constraints, nil
- }
-
- func (h *PostgreSQL) disableTriggers(db *sql.DB, loadFn loadFunction) (err error) {
- defer func() {
- // re-enable triggers after load
- var sql string
- for _, table := range h.tables {
- sql += fmt.Sprintf("ALTER TABLE %s ENABLE TRIGGER ALL;", h.quoteKeyword(table))
- }
- if _, err2 := db.Exec(sql); err2 != nil && err == nil {
- err = err2
- }
- }()
-
- tx, err := db.Begin()
- if err != nil {
- return err
- }
-
- var sql string
- for _, table := range h.tables {
- sql += fmt.Sprintf("ALTER TABLE %s DISABLE TRIGGER ALL;", h.quoteKeyword(table))
- }
- if _, err = tx.Exec(sql); err != nil {
- return err
- }
-
- if err = loadFn(tx); err != nil {
- tx.Rollback()
- return err
- }
-
- return tx.Commit()
- }
-
- func (h *PostgreSQL) makeConstraintsDeferrable(db *sql.DB, loadFn loadFunction) (err error) {
- defer func() {
- // ensure constraint being not deferrable again after load
- var sql string
- for _, constraint := range h.nonDeferrableConstraints {
- sql += fmt.Sprintf("ALTER TABLE %s ALTER CONSTRAINT %s NOT DEFERRABLE;", h.quoteKeyword(constraint.tableName), h.quoteKeyword(constraint.constraintName))
- }
- if _, err2 := db.Exec(sql); err2 != nil && err == nil {
- err = err2
- }
- }()
-
- var sql string
- for _, constraint := range h.nonDeferrableConstraints {
- sql += fmt.Sprintf("ALTER TABLE %s ALTER CONSTRAINT %s DEFERRABLE;", h.quoteKeyword(constraint.tableName), h.quoteKeyword(constraint.constraintName))
- }
- if _, err := db.Exec(sql); err != nil {
- return err
- }
-
- tx, err := db.Begin()
- if err != nil {
- return err
- }
- defer tx.Rollback()
-
- if _, err = tx.Exec("SET CONSTRAINTS ALL DEFERRED"); err != nil {
- return err
- }
-
- if err = loadFn(tx); err != nil {
- return err
- }
-
- return tx.Commit()
- }
-
- func (h *PostgreSQL) disableReferentialIntegrity(db *sql.DB, loadFn loadFunction) (err error) {
- // ensure sequences being reset after load
- defer func() {
- if err2 := h.resetSequences(db); err2 != nil && err == nil {
- err = err2
- }
- }()
-
- if h.UseAlterConstraint {
- return h.makeConstraintsDeferrable(db, loadFn)
- }
- return h.disableTriggers(db, loadFn)
- }
-
- func (h *PostgreSQL) resetSequences(db *sql.DB) error {
- for _, sequence := range h.sequences {
- _, err := db.Exec(fmt.Sprintf("SELECT SETVAL('%s', %d)", sequence, resetSequencesTo))
- if err != nil {
- return err
- }
- }
- return nil
- }
-
- func (h *PostgreSQL) isTableModified(q queryable, tableName string) (bool, error) {
- checksum, err := h.getChecksum(q, tableName)
- if err != nil {
- return false, err
- }
-
- oldChecksum := h.tablesChecksum[tableName]
-
- return oldChecksum == "" || checksum != oldChecksum, nil
- }
-
- func (h *PostgreSQL) afterLoad(q queryable) error {
- if h.tablesChecksum != nil {
- return nil
- }
-
- h.tablesChecksum = make(map[string]string, len(h.tables))
- for _, t := range h.tables {
- checksum, err := h.getChecksum(q, t)
- if err != nil {
- return err
- }
- h.tablesChecksum[t] = checksum
- }
- return nil
- }
-
- func (h *PostgreSQL) getChecksum(q queryable, tableName string) (string, error) {
- sqlStr := fmt.Sprintf(`
- SELECT md5(CAST((array_agg(t.*)) AS TEXT))
- FROM %s AS t
- `,
- h.quoteKeyword(tableName),
- )
-
- var checksum sql.NullString
- if err := q.QueryRow(sqlStr).Scan(&checksum); err != nil {
- return "", err
- }
- return checksum.String, nil
- }
-
- func (*PostgreSQL) quoteKeyword(s string) string {
- parts := strings.Split(s, ".")
- for i, p := range parts {
- parts[i] = fmt.Sprintf(`"%s"`, p)
- }
- return strings.Join(parts, ".")
- }
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