Cache::Memcached and converting warnings to fatal

InfiniteLoop has asked for the wisdom of the Perl Monks concerning the following question:

Greetings,
Im using Cache::Memcached in my script. The following call to stats() will throw warnings if the memcached server is not running:

use warnings;
use Cache::Memcached;
my $memd = new Cache::Memcached {servers => ["$host:$port"]};
my $stats = $memd->stats();
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I want to trap such warnings as errors (so I can eval/die in my code), hence I tried this in my code:

use warnings FATAL => 'all';
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Since, the above pragma will not "leak across files" according to perllexwarn, Im forced to do this:

 $SIG{'__WARN__'} = sub { die $_[0]};
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not that anything is wrong with setting up signal handlers, I want to know if I can somehow use the warnings pragma to achieve the same. Thanks.

Comment on Cache::Memcached and converting warnings to fatal Select or Download Code

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Re: Cache::Memcached and converting warnings to fatal by mscharrer (Hermit) on Apr 21, 2008 at 19:50 UTC
AFIK you can't use the warnings pragma to achieve the same, because its, as you already said, doesn't effect other scopes. Even the funny idea to do `# Inside your script: package Cache::Memcached; use warnings FATAL => 'all'; package main; [...]` [download] would help :-) Just use the handler. This is also mentioned in the perldoc page of `eval`. Please don't forget to use the `local` statement to make the handler local to your closure: `my $stats = eval { local $SIG{'__WARN__'} = sub { die }; $memd->stats(); } if ($@) { # No stats!! [...] }` [download] I also would remove the argument to `die` as long you don't want the warning message, which is now the error message, printed. Normally you do a `warn $@ if $@` or similar.	[reply] [d/l] [select]
Re: Cache::Memcached and converting warnings to fatal by Narveson (Chaplain) on Apr 21, 2008 at 21:05 UTC
I want to trap such warnings as errors (so I can eval/die in my code) What is the return value from `stats()` when the warning is thrown? Is it logically false? If so, you can say `use Fatal qw(Cache::Memcached::stats);` Of course, if this works, you can equally well say `my $stats = $memd->stats() or die;` and since you aren't doing that, I guess your failed `stats()` calls have been returning true values. I would file a bug report.	[reply] [d/l] [select]
Re: Cache::Memcached and converting warnings to fatal by rhesa (Vicar) on Apr 21, 2008 at 21:40 UTC
This doesn't scale when you add more memcached nodes. Just because one node is down, doesn't mean you won't get stats for the other ones. I just ignore the warnings (although it is noisy).	[reply]


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