In the following snippet
package ...
var Conn *sql.DB // outer Conn
func Init(user, pwd, dbname string, port int) {
Conn, err := sql.Open("postgres", "... args") // inner Conn
// ..
}
the inner Conn is a new variable and outer Conn will remain null.
By explicitly defining err and replacing the short variable definition with assignment it seems to properly init the outer Conn variable
var err error
Conn, err = sql.Open("postgres", "... args") // inner Conn
Is there a simpler way to specify the inner Conn should not really be a scoped variable but instead the global Conn variable? I'm thinking something like package.Conn, but that's invalid inside the package itself.
Nope, that's it. := is just a shortcut to New() (https://golang.org/doc/effective_go.html#allocation_new) variable declaration (var foo int). A more idiomatic approach (and better design in general) is to return the connection and not to use global variables.
func Init(user string, pwd string, dbname string, port int) (*sql.DB, error) {
// ...
}
Dependency injection is your friend, try not to break scope.
No, there is no shorthand for this. := always assigns to variables in the current (innermost) scope, creating new variables if necessary. To assign to any variables outside the current scope, you must use = instead of :=, and in the case of multiple-assignment this means that all variables must be pre-declared.