DB error standardization

[derkan]

Added a new ParseError method to Adapter interface which parses adapter's error and provides error standardization like:

import (
	"github.com/samonzeweb/godb/dberror"
)
func () string{ 
    if err := db.Insert(&Book).Do(); err!=nil {
        if e, ok := err.(dberror.UniqueConstraint); ok {
		return fmt.Sprintf("Record with this value already exists, field:%s",e.Field)
	}
	if e, ok := err.(dberror.CheckConstraint); ok {
		return fmt.Sprintf("Record data for column %s is not valid",e.Field)
	}
	if e, ok := err.(dberror.ForeignKeyConstraint); ok {
		return fmt.Sprintf("Referenced value error for column: %s", e.Field)
	}
        return err.Error()
    }
}

[samonzeweb]

Hi Derkan,

I like it, really useful, easily expandable, original errors are preserved, types are common between adapters 👍

But there is one downside : public API is broken. Yes I'm a pain in the neck in this case, sorry. But I think the problem is rather simple to solve.

For a v2, something like this will simply be good enough. For now we can not break others code. But as it's really useful we can add this behaviour as optional. The idea is to have a method UseErrorParser to set a flag. According to its value you either returns the raw error (legacy mode, by default) or new parsed errors :

type DB struct {
	...
	// Optional error parsing by adapters (false by default = legacy mode)
	// Will probably be the default behaviour in new major release.
	useErrorParser bool
}

...

// UseErrorParser will allow adapters to parse errors and wrap ones returned by drivers
func (db *DB) UseErrorParser() {
	db.useErrorParser = true
}

The Clone method need to copy this new field.

In sqlrunner.gosomething like

	if err != nil {
		db.logExecutionErr(err, query, arguments)
		if db.useErrorParser {
			return nil, db.adapter.ParseError(err)
		} else {
			return nil, err
		}
	}

Is it ok for you ? Something I missed ?

Sam.

[derkan]

Good catch. 👍 Thank you. I've implemented changes as you suggested.