1 package Object::Remote::Logging;
4 use Scalar::Util qw(blessed);
5 use Object::Remote::Logging::Logger;
7 use Carp qw(carp croak);
9 extends 'Log::Contextual';
11 exports(qw( ____ router arg_levels ));
14 our $Router_Instance ||= do {
15 require Object::Remote::Logging::Router;
16 Object::Remote::Logging::Router->new;
20 #log level descriptions
21 #info - standard log level - normal program output for the end user
22 #warn - output for program that is executing quietly
23 #error - output for program that is running more quietly
24 #fatal - it is not possible to continue execution; this level is as quiet as is possible
25 #verbose - output for program executing verbosely (-v)
26 #debug - output for program running more verbosely (-v -v)
27 #trace - output for program running extremely verbosely (-v -v -v)
29 #the order of the log levels is significant with the
30 #most verbose level being first in the list and the
31 #most quiet as the last item
32 return [qw( trace debug verbose info warn error fatal )];
36 my ($class, $importer, $spec) = @_;
37 my $router = $class->router;
45 $class->SUPER::before_import($importer, $spec);
48 sub _parse_selections {
49 my ($selections_string) = @_;
53 #" * -Object::Remote::Logging Foo::Bar::Baz "
54 foreach(split(/\s+/, $selections_string)) {
68 #this is invoked on all nodes
70 my $level = $ENV{OBJECT_REMOTE_LOG_LEVEL};
71 my $format = $ENV{OBJECT_REMOTE_LOG_FORMAT};
72 my $selections = $ENV{OBJECT_REMOTE_LOG_SELECTIONS};
73 my %controller_should_log;
75 unless (defined $ENV{OBJECT_REMOTE_LOG_FORWARDING} && $ENV{OBJECT_REMOTE_LOG_FORWARDING} ne '') {
76 $ENV{OBJECT_REMOTE_LOG_FORWARDING} = 1;
79 return unless defined $level && $level ne '';
80 $format = "[%l %r] %s" unless defined $format;
81 $selections = __PACKAGE__ unless defined $selections;
82 %controller_should_log = _parse_selections($selections);
86 if (defined $Object::Remote::FatNode::REMOTE_NODE) {
87 #the connection id for the remote node comes in later
88 #as the controlling node inits remote logging
89 router()->_remote_metadata({ connection_id => undef });
93 my $logger = Object::Remote::Logging::Logger->new(
94 min_level => lc($level), format => $format,
95 level_names => Object::Remote::Logging::arg_levels(),
98 router()->connect(sub {
99 my $controller = $_[1]->{controller};
100 my $will_log = $controller_should_log{$controller};
102 $will_log = $controller_should_log{'*'} unless defined $will_log;
104 return unless $will_log;
105 #skip things from remote hosts because they log to STDERR
106 #when OBJECT_REMOTE_LOG_LEVEL is in effect
107 return if $_[1]->{remote}->{connection_id};
112 #this is invoked by the controlling node
114 sub init_remote_logging {
115 my ($self, %controller_info) = @_;
117 router()->_remote_metadata(\%controller_info);
118 router()->_forward_destination($controller_info{router}) if $ENV{OBJECT_REMOTE_LOG_FORWARDING};
127 Object::Remote::Logging - Logging subsystem for Object::Remote
131 use Object::Remote::Logging qw( :log :dlog arg_levels router );
133 @levels = qw( trace debug verbose info warn error fatal );
134 @levels = arg_levels(); #same result
136 $ENV{OBJECT_REMOTE_LOG_LEVEL} = 'trace'; #or other level name
137 $ENV{OBJECT_REMOTE_LOG_FORMAT} = '%l %t: %p::%m %s'; #and more
138 $ENV{OBJECT_REMOTE_LOG_SELECTIONS} = 'Object::Remote::Logging Some::Other::Subclass';
139 $ENV{OBJECT_REMOTE_LOG_SELECTIONS} = '* -Object::Remote::Logging';
140 $ENV{OBJECT_REMOTE_LOG_FORWARDING} = 0; #default 1
142 log_info { 'Trace log event' };
143 Dlog_verbose { "Debug event with Data::Dumper::Concise: $_" } { foo => 'bar' };
147 This is the logging framework for Object::Remote implemented as a subclass of
148 L<Log::Contextual> with a slightly incompatible API. This system allows
149 developers using Object::Remote and end users of that software to control
150 Object::Remote logging so operation can be tracked if needed. This is also
151 the API used to generate log messages inside the Object::Remote source code.
153 The rest of the logging system comes from L<Object::Remote::Logging::Logger>
154 which implements log rendering and output and L<Object::Remote::Logging::Router>
155 which delivers log events to the loggers.
159 Object::Remote logging is not enabled by default. If you need to immediately start
160 debugging set the OBJECT_REMOTE_LOG_LEVEL environment variable to either 'trace'
161 or 'debug'. This will enable logging to STDERR on the local and all remote Perl
162 interpreters. By default STDERR for all remote interpreters is passed through
163 unmodified so this is sufficient to receive logs generated anywhere Object::Remote
166 Every time the local interpreter creates a new Object::Remote::Connection the connection
167 is given an id that is unique to that connection on the local interpreter. The connection
168 id and other metadata is available in the log output via a log format string that can
169 be set via the OBJECT_REMOTE_LOG_FORMAT environment variable. The format string and
170 available metadata is documented in L<Object::Remote::Logging::Logger>. Setting this
171 environment variable on the local interpreter will cause it to be propagated to the
172 remote interpreter so all logs will be formated the same way.
174 This class is designed so any module can create their own logging sub-class using it.
175 With out any additional configuration the consumers of this logging class will
176 automatically be enabled via OBJECT_REMOTE_LOG_LEVEL and formated with
177 OBJECT_REMOTE_LOG_FORMAT but those additional log messages are not sent to STDERR.
178 By setting the OBJECT_REMOTE_LOG_SELECTIONS environment variable to a list of
179 class names seperated by spaces then logs generated by packages that use those classes
180 will be sent to STDERR. If the asterisk character (*) is used in the place of a class
181 name then all class names will be selected by default instead of ignored. An individual
182 class name can be turned off by prefixing the name with a hypen character (-). This is
183 also a configuration item that is forwarded to the remote interpreters so all logging
186 Regardless of OBJECT_REMOTE_LOG_LEVEL the logging system is still active and loggers
187 can access the stream of log messages to format and output them. Internally
188 OBJECT_REMOTE_LOG_LEVEL causes an L<Object::Remote::Logging::Logger> to be built
189 and connected to the L<Object::Remote::Logging::Router> instance. It is also possible
190 to manually build a logger instance and connect it to the router. See the documentation
191 for the logger and router classes.
193 The logging system also supports a method of forwarding log messages from remote
194 interpreters to the local interpreter. Forwarded log messages are generated in the
195 remote interpreter and the logger for the message is invoked in the local interpreter.
196 Sub-classes of Object::Remote::Logging will have log messages forwarded automatically.
197 Loggers receive forwarded log messages exactly the same way as non-forwarded messages
198 except a forwarded message includes extra metadata about the remote interpreter. Log
199 forwarding is enabled by default but comes with a performance hit; to disable it set the
200 OBJECT_REMOTE_LOG_FORWARDING environment variable to 0. See L<Object::Remote::Logging::Router>.
202 =head1 EXPORTABLE SUBROUTINES
208 Returns an array reference that contains the ordered list of level names
209 with the lowest log level first and the highest log level last.
213 Returns the instance of L<Object::Remote::Logging::Router> that is in use. The router
214 instance is used in combination with L<Object::Remote::Logging::Logger> objects to
215 select then render and output log messages.
217 =item log_<level> and Dlog_<level>
219 These methods come direct from L<Log::Contextual>; see that documentation for a
220 complete reference. For each of the log level names there are subroutines with the log_
221 and Dlog_ prefix that will generate the log message. The first argument is a code block
222 that returns the log message contents and the optional further arguments are both passed
223 to the block as the argument list and returned from the log method as a list.
225 log_trace { "A fine log message $_[0] " } 'if I do say so myself';
226 %hash = Dlog_trace { "Very handy: $_" } ( foo => 'bar' );
228 =item logS_<level> and DlogS_<level>
230 Works just like log_ and Dlog_ except returns only the first argument as a scalar value.
232 my $beverage = logS_info { "Customer ordered $_[0]" } 'Coffee';
238 Object::Remote uses an ordered list of log level names with the lowest level
239 first and the highest level last. The list of level names can be accessed via
240 the arg_levels method which is exportable to the consumer of this class. The log
247 As much information about operation as possible including multiple line dumps of
248 large content. Tripple verbose operation (-v -v -v).
252 Messages about operations that could hang as well as internal state changes,
253 results from method invocations, and information useful when looking for faults.
254 Double verbose operation (-v -v).
258 Additional optional messages to the user that can be enabled at their will. Single
259 verbose operation (-v).
263 Messages from normal operation that are intended to be displayed to the end
264 user if quiet operation is not indicated and more verbose operation is not
269 Something wasn't supposed to happen but did. Operation was not impacted but
270 otherwise the event is noteworthy. Single quiet operation (-q).
274 Something went wrong. Operation of the system may continue but some operation
275 has most definitely failed. Double quiet operation (-q -q).
279 Something went wrong and recovery is not possible. The system should stop operating
280 as soon as possible. Tripple quiet operation (-q -q -q).