shyp / go-dberror

parsing postgres errors

Readable database errors

Do you like forcing constraint validation down into the database, but dislike the native error messages returned by Postgres?

invalid input syntax for uuid: "foo"

invalid input value for enum account_status: "blah"

new row for relation "accounts" violates check constraint "accounts_balance_check"

null value in column "id" violates not-null constraint

This library attempts to parse those error messages and return error messages that you can expose via your API.

No id was provided. Please provide a id

Cannot write a negative balance

Invalid input syntax for type uuid: "foo"

Invalid account_status: "blah"

Can't save to payments because the account_id (91f47e99-d616-4d8c-9c02-cbd13bceac60) isn't present in the accounts table

A email already exists with this value ([email protected])

In addition, this library exports common Postgres error codes, so you can check against them in your application.

Basic Usage

import dberror "github.com/Shyp/go-dberror"

func main() {
	_, err := db.Exec("INSERT INTO accounts (id) VALUES (null)")
	dberr := dberror.GetError(err)
	switch e := dberr.(type) {
	case *dberror.Error:
		fmt.Println(e.Error()) // "No id was provided. Please provide a id"
	default:
		// not a pq error
}

Database Constraints

Failed check constraints are tricky - the native error messages just say "failed", and don't reference a column.

So you can define your own constraint handlers, and then register them:

import dberror "github.com/Shyp/go-dberror"
import "github.com/lib/pq"

func init()
	constraint := &dberror.Constraint{
		Name: "accounts_balance_check",
		GetError: func(e *pq.Error) *dberror.Error {
			return &dberror.Error{
				Message:  "Cannot write a negative balance",
				Severity: e.Severity,
				Table:    e.Table,
				Detail:   e.Detail,
				Code:     string(e.Code),
			}
		},
	}
	dberror.RegisterConstraint(constraint)

	// test.AssertEquals(t, e.Error(), "Cannot write a negative balance")
}

If we get a constraint failure, we'll call your GetError handler, to get a well-formatted message.

go-dberror's Issues

Please add MIT License

Hi,
I wrote this project while I was at Shyp and intended for it to be used by others. Apparently I forgot to put a LICENSE file on it. This means that it's not usable by anyone.

Could you put a LICENSE file on it?

Thanks,
Kevin

Support Raw string of error

I want to give it raw error message and parse that for me