mirror of
https://github.com/TECHNOFAB11/dbmate.git
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128 lines
2.9 KiB
Go
128 lines
2.9 KiB
Go
package main
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import (
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"database/sql"
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"fmt"
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"github.com/lib/pq"
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"net/url"
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)
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// PostgresDriver provides top level database functions
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type PostgresDriver struct {
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}
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// Open creates a new database connection
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func (drv PostgresDriver) Open(u *url.URL) (*sql.DB, error) {
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return sql.Open("postgres", u.String())
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}
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func (drv PostgresDriver) openPostgresDB(u *url.URL) (*sql.DB, error) {
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// connect to postgres database
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postgresURL := *u
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postgresURL.Path = "postgres"
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return drv.Open(&postgresURL)
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}
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// CreateDatabase creates the specified database
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func (drv PostgresDriver) CreateDatabase(u *url.URL) error {
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name := databaseName(u)
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fmt.Printf("Creating: %s\n", name)
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db, err := drv.openPostgresDB(u)
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if err != nil {
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return err
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}
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defer mustClose(db)
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_, err = db.Exec(fmt.Sprintf("create database %s",
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pq.QuoteIdentifier(name)))
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return err
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}
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// DropDatabase drops the specified database (if it exists)
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func (drv PostgresDriver) DropDatabase(u *url.URL) error {
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name := databaseName(u)
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fmt.Printf("Dropping: %s\n", name)
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db, err := drv.openPostgresDB(u)
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if err != nil {
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return err
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}
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defer mustClose(db)
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_, err = db.Exec(fmt.Sprintf("drop database if exists %s",
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pq.QuoteIdentifier(name)))
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return err
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}
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// DatabaseExists determines whether the database exists
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func (drv PostgresDriver) DatabaseExists(u *url.URL) (bool, error) {
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name := databaseName(u)
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db, err := drv.openPostgresDB(u)
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if err != nil {
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return false, err
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}
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defer mustClose(db)
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exists := false
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err = db.QueryRow("select true from pg_database where datname = $1", name).
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Scan(&exists)
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if err == sql.ErrNoRows {
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return false, nil
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}
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return exists, err
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}
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// CreateMigrationsTable creates the schema_migrations table
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func (drv PostgresDriver) CreateMigrationsTable(db *sql.DB) error {
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_, err := db.Exec(`create table if not exists schema_migrations (
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version varchar(255) primary key)`)
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return err
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}
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// SelectMigrations returns a list of applied migrations
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// with an optional limit (in descending order)
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func (drv PostgresDriver) SelectMigrations(db *sql.DB, limit int) (map[string]bool, error) {
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query := "select version from schema_migrations order by version desc"
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if limit >= 0 {
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query = fmt.Sprintf("%s limit %d", query, limit)
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}
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rows, err := db.Query(query)
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if err != nil {
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return nil, err
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}
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defer mustClose(rows)
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migrations := map[string]bool{}
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for rows.Next() {
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var version string
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if err := rows.Scan(&version); err != nil {
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return nil, err
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}
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migrations[version] = true
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}
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return migrations, nil
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}
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// InsertMigration adds a new migration record
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func (drv PostgresDriver) InsertMigration(db Transaction, version string) error {
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_, err := db.Exec("insert into schema_migrations (version) values ($1)", version)
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return err
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}
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// DeleteMigration removes a migration record
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func (drv PostgresDriver) DeleteMigration(db Transaction, version string) error {
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_, err := db.Exec("delete from schema_migrations where version = $1", version)
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return err
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}
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