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

[Matthias Bolte]

2010/6/11 Daniel P. Berrange <berrange at redhat.com>:
> 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
>

Maybe something like having a scheme-to-driver mapping table would be
nice, instead of asking each driver.

Thanks, pushed.

Matthias