// pgConnect: Open the Postgres database. Returns any error
// encountered during the open.
func pgConnect() (string, error) {
cfg, err := pgx.ParseURI(pgUrl)
if err != nil {
err = fmt.Errorf("Parse failure on Postgres URI %q: %v", pgUrl, err)
return "", err
}
conn, err := pgx.Connect(cfg)
if err != nil {
err = fmt.Errorf("Couldn't connect to db at %q: %v", pgUrl, err)
return "", err
}
pgConn = conn
return pgUrl, nil
}
// apply dataFunctions to the database. Each is applied in a
// separate transaction, so later ones can rely on the effect of
// earlier ones having been committed.
func applyFunctions(fns []dataFunction) error {
url := os.Getenv("DATABASE_URL")
if url == "" {
url = "postgres://localhost/susen?sslmode=disable"
}
// open the database, defer the close
cfg, err := pgx.ParseURI(url)
if err != nil {
return err
}
conn, err := pgx.Connect(cfg)
if err != nil {
return err
}
defer conn.Close()
// helper that runs each function inside a transaction, and
// ensures that any problems are rolled back.
runFunc := func(fn dataFunction) error {
tx, err := conn.Begin()
if err != nil {
return err
}
defer func() {
if e := recover(); e != nil {
tx.Rollback()
panic(e)
}
}()
if err := fn(tx); err != nil {
tx.Rollback()
return err
}
return tx.Commit()
}
// run the functions
for _, fn := range fns {
if err := runFunc(fn); err != nil {
return fmt.Errorf("%v failed: %v", fn, err)
}
}
return nil
}