gitroast/vendor/gopkg.in/testfixtures.v2/postgresql.go

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package testfixtures
import (
"database/sql"
"fmt"
"strings"
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)
// 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
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}
type pgConstraint struct {
tableName string
constraintName string
}
func (h *PostgreSQL) init(db *sql.DB) error {
var err error
h.tables, err = h.tableNames(db)
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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
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}
func (h *PostgreSQL) tableNames(q queryable) ([]string, error) {
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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)
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if err != nil {
return nil, err
}
defer rows.Close()
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for rows.Next() {
var table string
if err = rows.Scan(&table); err != nil {
return nil, err
}
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tables = append(tables, table)
}
if err = rows.Err(); err != nil {
return nil, err
}
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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'
`
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rows, err := q.Query(sql)
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if err != nil {
return nil, err
}
defer rows.Close()
var sequences []string
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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
}
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return sequences, nil
}
func (*PostgreSQL) getNonDeferrableConstraints(q queryable) ([]pgConstraint, error) {
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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)
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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 {
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return nil, err
}
constraints = append(constraints, constraint)
}
if err = rows.Err(); err != nil {
return nil, err
}
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return constraints, nil
}
func (h *PostgreSQL) disableTriggers(db *sql.DB, loadFn loadFunction) (err error) {
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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
}
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}()
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) {
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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
}
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}()
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()
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if _, err = tx.Exec("SET CONSTRAINTS ALL DEFERRED"); err != nil {
return err
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}
if err = loadFn(tx); err != nil {
return err
}
return tx.Commit()
}
func (h *PostgreSQL) disableReferentialIntegrity(db *sql.DB, loadFn loadFunction) (err error) {
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// ensure sequences being reset after load
defer func() {
if err2 := h.resetSequences(db); err2 != nil && err == nil {
err = err2
}
}()
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if h.UseAlterConstraint {
return h.makeConstraintsDeferrable(db, loadFn)
}
return h.disableTriggers(db, loadFn)
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}
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, ".")
}