[libvirt] [PATCH] Improve error message for disabled client-side drivers

[Daniel P. Berrange]

On Thu, Jun 10, 2010 at 01:28:29AM +0200, Matthias Bolte wrote:
> Report that libvirt was built without that driver instead of
> trying to connect to a libvirtd, when we know that this is
> going to fail.
> ---
> 
> I had this on my todo list for a while now, because multiple people on
> the mailing list and on IRC reported problems that can be summarized as:
> 
> "I just built/installed libvirt and want to connect to an ESX server,
> but libvirt complains about missing certificates or wants to connect to
> a non-existing libvirtd on the ESX server. I don't get it..."
> 
> The problem was always the same: libvirt built without the ESX driver.
> But people don't get that, because libvirt reported cryptic errors in
> that situation.
> 
> I decided to fix this now because the problem was reported again on
> IRC today.
> 
>  src/libvirt.c |   28 ++++++++++++++++++++++++++++
>  1 files changed, 28 insertions(+), 0 deletions(-)
> 
> diff --git a/src/libvirt.c b/src/libvirt.c
> index 2754fd0..2487b82 100644
> --- a/src/libvirt.c
> +++ b/src/libvirt.c
> @@ -1210,6 +1210,34 @@ do_open (const char *name,
>      ret->flags = flags & VIR_CONNECT_RO;
>  
>      for (i = 0; i < virDriverTabCount; i++) {
> +        /* We're going to probe the remote driver next. So we have already
> +         * probed all other client-side-only driver before, but none of them
> +         * accepted the URI.
> +         * If the scheme corresponds to a known but disabled client-side-only
> +         * driver then report a useful error, instead of a cryptic one about
> +         * not being able to connect to libvirtd or not being able to find
> +         * certificates. */
> +        if (virDriverTab[i]->no == VIR_DRV_REMOTE &&
> +            ret->uri != NULL && ret->uri->scheme != NULL &&
> +            (
> +# ifndef WITH_PHYP
> +             STRCASEEQ(ret->uri->scheme, "phyp") ||
> +# endif
> +# ifndef WITH_ESX
> +             STRCASEEQ(ret->uri->scheme, "esx") ||
> +             STRCASEEQ(ret->uri->scheme, "gsx") ||
> +# endif
> +# ifndef WITH_XENAPI
> +             STRCASEEQ(ret->uri->scheme, "xenapi") ||
> +# endif
> +             false)) {
> +            virReportErrorHelper(NULL, VIR_FROM_NONE, VIR_ERR_INVALID_ARG,
> +                                 __FILE__, __FUNCTION__, __LINE__,
> +                                 _("libvirt was built without the '%s' driver"),
> +                                 ret->uri->scheme);
> +            goto failed;
> +        }
> +
>          DEBUG("trying driver %d (%s) ...",
>                i, virDriverTab[i]->name);
>          res = virDriverTab[i]->open (ret, auth, flags);

ACK, this looks fine to me.  One day I'd like to change the way we pick
the drivers during the open method, but that's faar too invasive for
now.

Regards,
Daniel
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