story of a failure

[roger peppe]

On Apr 26, 2013 7:22 PM, "Gustavo Niemeyer" <gustavo at niemeyer.net> wrote:
>
> My 2 BRL cents:
>
> "cannot get login entity: cannot get user "admin": mongo query failed:
> cannot acquire socket: cannot log in: error authorizing user "admin":
> request failed: cannot read reply: EOF"
>
> This looks pretty good in comparison:
>
> "cannot get login entity: cannot get user "admin": database query failed:
EOF"
>
> An EOF when talking to a database is generally a well understood concept.

Agreed that that error is less verbose and probably fine for many purposes,
but from the point of view of diagnosing this problem, it also throws away
important information - are we seeing this error when talking to an
existing connection, or when making a new one?

I am concerned that currently by default we add no context to errors, and
this has led us to the situation I described. After I have pointed out a
place where a reported error is bad, we can jump in and change the code to
add some context.

But that's too late! I would like a decent error message when we encounter
conditions that have never been seen before. That is, I would like it if we
erred on the overly verbose side, adjusting things later if we found them
too verbose in practice - the opposite to our current approach.

> On Fri, Apr 26, 2013 at 3:09 PM, roger peppe <rogpeppe at gmail.com> wrote:
> > After an experience trying to get to the bottom of a problem found when
> > load-testing juju this morning, I was inspired to write this.
> >
> >
https://docs.google.com/a/canonical.com/document/d/12i8jFLeXK95kz4ztzFy8FHor4Vtg39u0QkiyEW3dQaA/edit?usp=sharing
> >
> > PS Apologies for the awful formatting. I should have stuck to plain
text.
> >
> >
> > --
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> >
>
>
>
> --
>
> gustavo @ http://niemeyer.net
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