gonews/vendor/github.com/pressly/goose/migration_sql.go

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2019-09-09 21:52:32 +05:00
package goose
import (
"bufio"
"bytes"
"database/sql"
"fmt"
"io"
"os"
"regexp"
"strings"
"sync"
"github.com/pkg/errors"
)
const sqlCmdPrefix = "-- +goose "
const scanBufSize = 4 * 1024 * 1024
var bufferPool = sync.Pool{
New: func() interface{} {
return make([]byte, scanBufSize)
},
}
// Checks the line to see if the line has a statement-ending semicolon
// or if the line contains a double-dash comment.
func endsWithSemicolon(line string) bool {
scanBuf := bufferPool.Get().([]byte)
defer bufferPool.Put(scanBuf)
prev := ""
scanner := bufio.NewScanner(strings.NewReader(line))
scanner.Buffer(scanBuf, scanBufSize)
scanner.Split(bufio.ScanWords)
for scanner.Scan() {
word := scanner.Text()
if strings.HasPrefix(word, "--") {
break
}
prev = word
}
return strings.HasSuffix(prev, ";")
}
// Split the given sql script into individual statements.
//
// The base case is to simply split on semicolons, as these
// naturally terminate a statement.
//
// However, more complex cases like pl/pgsql can have semicolons
// within a statement. For these cases, we provide the explicit annotations
// 'StatementBegin' and 'StatementEnd' to allow the script to
// tell us to ignore semicolons.
func getSQLStatements(r io.Reader, direction bool) ([]string, bool, error) {
var buf bytes.Buffer
scanBuf := bufferPool.Get().([]byte)
defer bufferPool.Put(scanBuf)
scanner := bufio.NewScanner(r)
scanner.Buffer(scanBuf, scanBufSize)
// track the count of each section
// so we can diagnose scripts with no annotations
upSections := 0
downSections := 0
statementEnded := false
ignoreSemicolons := false
directionIsActive := false
tx := true
stmts := []string{}
for scanner.Scan() {
line := scanner.Text()
// handle any goose-specific commands
if strings.HasPrefix(line, sqlCmdPrefix) {
cmd := strings.TrimSpace(line[len(sqlCmdPrefix):])
switch cmd {
case "Up":
directionIsActive = (direction == true)
upSections++
break
case "Down":
directionIsActive = (direction == false)
downSections++
break
case "StatementBegin":
if directionIsActive {
ignoreSemicolons = true
}
break
case "StatementEnd":
if directionIsActive {
statementEnded = (ignoreSemicolons == true)
ignoreSemicolons = false
}
break
case "NO TRANSACTION":
tx = false
break
}
}
if !directionIsActive {
continue
}
if _, err := buf.WriteString(line + "\n"); err != nil {
return nil, false, fmt.Errorf("io err: %v", err)
}
// Wrap up the two supported cases: 1) basic with semicolon; 2) psql statement
// Lines that end with semicolon that are in a statement block
// do not conclude statement.
if (!ignoreSemicolons && endsWithSemicolon(line)) || statementEnded {
statementEnded = false
stmts = append(stmts, buf.String())
buf.Reset()
}
}
if err := scanner.Err(); err != nil {
return nil, false, fmt.Errorf("scanning migration: %v", err)
}
// diagnose likely migration script errors
if ignoreSemicolons {
return nil, false, fmt.Errorf("parsing migration: saw '-- +goose StatementBegin' with no matching '-- +goose StatementEnd'")
}
if bufferRemaining := strings.TrimSpace(buf.String()); len(bufferRemaining) > 0 {
return nil, false, fmt.Errorf("parsing migration: unexpected unfinished SQL query: %s. potential missing semicolon", bufferRemaining)
}
if upSections == 0 && downSections == 0 {
return nil, false, fmt.Errorf("parsing migration: no Up/Down annotations found, so no statements were executed. See https://bitbucket.org/liamstask/goose/overview for details")
}
return stmts, tx, nil
}
// Run a migration specified in raw SQL.
//
// Sections of the script can be annotated with a special comment,
// starting with "-- +goose" to specify whether the section should
// be applied during an Up or Down migration
//
// All statements following an Up or Down directive are grouped together
// until another direction directive is found.
func runSQLMigration(db *sql.DB, sqlFile string, v int64, direction bool) error {
f, err := os.Open(sqlFile)
if err != nil {
return errors.Wrap(err, "failed to open SQL migration file")
}
defer f.Close()
statements, useTx, err := getSQLStatements(f, direction)
if err != nil {
return err
}
if useTx {
// TRANSACTION.
printInfo("Begin transaction\n")
tx, err := db.Begin()
if err != nil {
errors.Wrap(err, "failed to begin transaction")
}
for _, query := range statements {
printInfo("Executing statement: %s\n", clearStatement(query))
if _, err = tx.Exec(query); err != nil {
printInfo("Rollback transaction\n")
tx.Rollback()
return errors.Wrapf(err, "failed to execute SQL query %q", clearStatement(query))
}
}
if direction {
if _, err := tx.Exec(GetDialect().insertVersionSQL(), v, direction); err != nil {
printInfo("Rollback transaction\n")
tx.Rollback()
return errors.Wrap(err, "failed to insert new goose version")
}
} else {
if _, err := tx.Exec(GetDialect().deleteVersionSQL(), v); err != nil {
printInfo("Rollback transaction\n")
tx.Rollback()
return errors.Wrap(err, "failed to delete goose version")
}
}
printInfo("Commit transaction\n")
if err := tx.Commit(); err != nil {
return errors.Wrap(err, "failed to commit transaction")
}
return nil
}
// NO TRANSACTION.
for _, query := range statements {
printInfo("Executing statement: %s\n", clearStatement(query))
if _, err := db.Exec(query); err != nil {
return errors.Wrapf(err, "failed to execute SQL query %q", clearStatement(query))
}
}
if _, err := db.Exec(GetDialect().insertVersionSQL(), v, direction); err != nil {
return errors.Wrap(err, "failed to insert new goose version")
}
return nil
}
func printInfo(s string, args ...interface{}) {
if verbose {
log.Printf(s, args...)
}
}
var (
matchSQLComments = regexp.MustCompile(`(?m)^--.*$[\r\n]*`)
matchEmptyLines = regexp.MustCompile(`(?m)^$[\r\n]*`)
)
func clearStatement(s string) string {
s = matchSQLComments.ReplaceAllString(s, ``)
return matchEmptyLines.ReplaceAllString(s, ``)
}