forked from simonklee/goose
/
migration_sql.go
170 lines (138 loc) · 3.97 KB
/
migration_sql.go
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package goose
import (
"bufio"
"bytes"
"database/sql"
"io"
"log"
"os"
"path/filepath"
"strings"
)
const sqlCmdPrefix = "-- +goose "
func endsWithSemicolon(line string) bool {
prev := ""
scanner := bufio.NewScanner(strings.NewReader(line))
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 splitSQLStatements(r io.Reader, direction bool) (stmts []string) {
var buf bytes.Buffer
scanner := bufio.NewScanner(r)
// track the count of each section
// so we can diagnose scripts with no annotations
upSections := 0
downSections := 0
statementEnded := false
ignoreSemicolons := false
directionIsActive := false
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
}
}
if !directionIsActive {
continue
}
if _, err := buf.WriteString(line + "\n"); err != nil {
log.Fatalf("io err: %v", err)
}
if !ignoreSemicolons && (statementEnded || endsWithSemicolon(line)) {
statementEnded = false
stmts = append(stmts, buf.String())
buf.Reset()
}
}
if err := scanner.Err(); err != nil {
log.Fatalf("scanning migration: %v", err)
}
// diagnose likely migration script errors
if ignoreSemicolons {
log.Println("WARNING: saw '-- +goose StatementBegin' with no matching '-- +goose StatementEnd'")
}
if upSections == 0 && downSections == 0 {
log.Fatalf(`ERROR: no Up/Down annotations found, so no statements were executed.
See https://github.com/simonz05/goose/overview for details.`)
}
return
}
// 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(conf *DBConf, db *sql.DB, script string, v int64, direction bool) error {
txn, err := db.Begin()
if err != nil {
log.Fatal("db.Begin:", err)
}
f, err := os.Open(script)
if err != nil {
log.Fatal(err)
}
// find each statement, checking annotations for up/down direction
// and execute each of them in the current transaction
for _, query := range splitSQLStatements(f, direction) {
if _, err = txn.Exec(query); err != nil {
txn.Rollback()
log.Fatalf("FAIL %s (%v), quitting migration.", filepath.Base(script), err)
return err
}
}
if err = finalizeMigration(conf, txn, direction, v); err != nil {
log.Fatalf("error finalizing migration %s, quitting. (%v)", filepath.Base(script), err)
}
return nil
}
// Update the version table for the given migration,
// and finalize the transaction.
func finalizeMigration(conf *DBConf, txn *sql.Tx, direction bool, v int64) error {
// XXX: drop goose_db_version table on some minimum version number?
d := conf.Driver.Dialect
if _, err := txn.Exec(d.insertVersionSql(), v, direction); err != nil {
txn.Rollback()
return err
}
return txn.Commit()
}