[collectd] [PATCH 6/6] Collectd.pm: Improved error handling of failed callbacks.

[Sebastian Harl]

If call_by_name() failed, it will be handled the same way as if the callback
returned "false". The $@ variable may now be used by plugins as well to
describe errors in greater detail.

Signed-off-by: Sebastian Harl <sh at tokkee.org>
---
 bindings/perl/Collectd.pm |   27 ++++++++++++++++++---------
 src/collectd-perl.pod     |    3 +++
 2 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/bindings/perl/Collectd.pm b/bindings/perl/Collectd.pm
index 8c3159c..2de9885 100644
--- a/bindings/perl/Collectd.pm
+++ b/bindings/perl/Collectd.pm
@@ -143,12 +143,21 @@ sub plugin_call_all {
 		$cb_name = $p->{'cb_name'};
 		$status = call_by_name (@_);
 
-		if (! defined $status) {
+		if (! $status) {
+			my $err = undef;
+
+			if ($@) {
+				$err = $@;
+			}
+			else {
+				$err = "callback returned false";
+			}
+
 			if (TYPE_LOG != $type) {
-				ERROR ("Could not execute callback \"$cb_name\": $@");
+				ERROR ("Execution of callback \"$cb_name\" failed: $err");
 			}
 
-			next;
+			$status = 0;
 		}
 
 		if ($status) {
@@ -156,23 +165,23 @@ sub plugin_call_all {
 			$p->{'wait_time'} = 10;
 		}
 		elsif (TYPE_READ == $type) {
+			WARNING ("${plugin}->read() failed with status $status. "
+				. "Will suspend it for $p->{'wait_left'} seconds.");
+
 			$p->{'wait_left'} = $p->{'wait_time'};
 			$p->{'wait_time'} *= 2;
 
 			if ($p->{'wait_time'} > 86400) {
 				$p->{'wait_time'} = 86400;
 			}
-
-			WARNING ("${plugin}->read() failed with status $status. "
-				. "Will suspend it for $p->{'wait_left'} seconds.");
 		}
 		elsif (TYPE_INIT == $type) {
+			ERROR ("${plugin}->init() failed with status $status. "
+				. "Plugin will be disabled.");
+
 			foreach my $type (keys %types) {
 				plugin_unregister ($type, $plugin);
 			}
-
-			ERROR ("${plugin}->init() failed with status $status. "
-				. "Plugin will be disabled.");
 		}
 		elsif (TYPE_LOG != $type) {
 			WARNING ("${plugin}->$types{$type}() failed with status $status.");
diff --git a/src/collectd-perl.pod b/src/collectd-perl.pod
index 2b77667..73bacc6 100644
--- a/src/collectd-perl.pod
+++ b/src/collectd-perl.pod
@@ -103,6 +103,9 @@ be used to clean up the plugin (e.g. close sockets, ...).
 
 =back
 
+Any function may set the B<$@> variable to describe errors in more detail. The
+message will be passed on to the user using collectd's logging mechanism.
+
 See the documentation of the B<plugin_register> method in the section
 "METHODS" below for the number and types of arguments passed to each
 B<callback function>. This section also explains how to register B<callback
-- 
1.5.3.4

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