How to check for custom Postgres exceptions raised via RAISE EXCEPTION in Golang?

Question

I'm using Postgres with Golang via pgx

I've a trigger function something like the following:

CREATE OR REPLACE FUNCTION foo() 
RETURNS TRIGGER AS
$$
BEGIN
    IF (bar = 'baz') THEN
        -- something
    ELSE
        RAISE EXCEPTION 'oops error';
    END IF;
    RETURN NEW;
END;
$$
LANGUAGE plpgsql;

How do I check for oops error in Go code?

The way I'm doing it now is:

errOops := errors.New("ERROR: oops error (SQLSTATE P0001)")
err := myDBFunc()
if errors.Is(err, errOops) {

}

But I wonder if there's a better way other than relying on the hardcoded message.

score 3 · Accepted Answer · answered Oct 18 '22 at 12:05

3

Should have read the Wiki: Error Handling in pgx

So I can do:

var pgErr *pgconn.PgError
if errors.As(err, &pgErr) && pgErr.Code == "P0001" {

}

or something similar.

answered Oct 18 '22 at 12:05

Abhijit

468
8
22

score 1 · Answer 2 · answered Oct 18 '22 at 11:01

1

You can find that information in appendix A of the documentation: it will be a raise_exception, and the SQLSTATE is P0001.

answered Oct 18 '22 at 11:01

Laurenz Albe

209,280
17
206
263

1

Hi. Thanks for replying. But I meant how to check it in Golang code. The code only returns an `error` type which, if I marshal to JSON and log, I get the code and message etc. But the actual variable, let's call it `err` only has an `Error` method (as expected). – Abhijit Oct 18 '22 at 11:20
1

Great, you found the missing information yourself. – Laurenz Albe Oct 18 '22 at 12:20

How to check for custom Postgres exceptions raised via RAISE EXCEPTION in Golang?

2 Answers2