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 return unless defined $level;
76 $format = "[%l %r] %s" unless defined $format;
77 $selections = __PACKAGE__ unless defined $selections;
78 %controller_should_log = _parse_selections($selections);
82 if (defined $Object::Remote::FatNode::REMOTE_NODE) {
83 #the connection id for the remote node comes in later
84 #as the controlling node inits remote logging
85 router()->_remote_metadata({ connection_id => undef });
89 my $logger = Object::Remote::Logging::Logger->new(
90 min_level => lc($level), format => $format,
91 level_names => Object::Remote::Logging::arg_levels(),
94 router()->connect(sub {
95 my $controller = $_[1]->{controller};
96 my $will_log = $controller_should_log{$controller};
98 $will_log = $controller_should_log{'*'} unless defined $will_log;
100 return unless $will_log;
101 #skip things from remote hosts because they log to STDERR
102 #when OBJECT_REMOTE_LOG_LEVEL is in effect
103 return if $_[1]->{remote}->{connection_id};
108 #this is invoked by the controlling node
110 sub init_remote_logging {
111 my ($self, %controller_info) = @_;
113 router()->_remote_metadata(\%controller_info);
114 #TODO having an instance of an object in the remote interpreter causes it to hang
115 #on exit intermitently or leave a zombie laying around frequently - not a bug limited
117 router()->_forward_destination($controller_info{router}) if $ENV{OBJECT_REMOTE_LOG_FORWARDING};
126 Object::Remote::Logging - Logging subsystem for Object::Remote
130 use Object::Remote::Logging qw( :log :dlog arg_levels router );
132 @levels = qw( trace debug verbose info warn error fatal );
133 @levels = arg_levels(); #same result
135 $ENV{OBJECT_REMOTE_LOG_LEVEL} = 'trace'; #or other level name
136 $ENV{OBJECT_REMOTE_LOG_FORMAT} = '%l %t: %p::%m %s'; #and more
137 $ENV{OBJECT_REMOTE_LOG_SELECTIONS} = 'Object::Remote::Logging Some::Other::Subclass';
138 $ENV{OBJECT_REMOTE_LOG_SELECTIONS} = '* -Object::Remote::Logging';
139 $ENV{OBJECT_REMOTE_LOG_FORWARDING} = 0 || 1; #default 0
141 log_info { 'Trace log event' };
142 Dlog_verbose { "Debug event with Data::Dumper::Concise: $_" } { foo => 'bar' };
146 This is the logging framework for Object::Remote implemented as a subclass of
147 L<Log::Contextual> with a slightly incompatible API. This system allows
148 developers using Object::Remote and end users of that software to control
149 Object::Remote logging so operation can be tracked if needed. This is also
150 the API used to generate log messages inside the Object::Remote source code.
152 The rest of the logging system comes from L<Object::Remote::Logging::Logger>
153 which implements log rendering and output and L<Object::Remote::Logging::Router>
154 which delivers log events to the loggers.
158 Object::Remote logging is not enabled by default. If you need to immediately start
159 debugging set the OBJECT_REMOTE_LOG_LEVEL environment variable to either 'trace'
160 or 'debug'. This will enable logging to STDERR on the local and all remote Perl
161 interpreters. By default STDERR for all remote interpreters is passed through
162 unmodified so this is sufficient to receive logs generated anywhere Object::Remote
165 Every time the local interpreter creates a new Object::Remote::Connection the connection
166 is given an id that is unique to that connection on the local interpreter. The connection
167 id and other metadata is available in the log output via a log format string that can
168 be set via the OBJECT_REMOTE_LOG_FORMAT environment variable. The format string and
169 available metadata is documented in L<Object::Remote::Logging::Logger>. Setting this
170 environment variable on the local interpreter will cause it to be propagated to the
171 remote interpreter so all logs will be formated the same way.
173 This class is designed so any module can create their own logging sub-class using it.
174 With out any additional configuration the consumers of this logging class will
175 automatically be enabled via OBJECT_REMOTE_LOG_LEVEL and formated with
176 OBJECT_REMOTE_LOG_FORMAT but those additional log messages are not sent to STDERR.
177 By setting the OBJECT_REMOTE_LOG_SELECTIONS environment variable to a list of
178 class names seperated by spaces then logs generated by packages that use those classes
179 will be sent to STDERR. If the asterisk character (*) is used in the place of a class
180 name then all class names will be selected by default instead of ignored. An individual
181 class name can be turned off by prefixing the name with a hypen character (-). This is
182 also a configuration item that is forwarded to the remote interpreters so all logging
185 Regardless of OBJECT_REMOTE_LOG_LEVEL the logging system is still active and loggers
186 can access the stream of log messages to format and output them. Internally
187 OBJECT_REMOTE_LOG_LEVEL causes an L<Object::Remote::Logging::Logger> to be built
188 and connected to the L<Object::Remote::Logging::Router> instance. It is also possible
189 to manually build a logger instance and connect it to the router. See the documentation
190 for the logger and router classes.
192 The logging system also supports a method of forwarding log messages from remote
193 interpreters to the local interpreter. Forwarded log messages are generated in the
194 remote interpreter and the logger for the message is invoked in the local interpreter.
195 Sub-classes of Object::Remote::Logging will have log messages forwarded automatically.
196 Loggers receive forwarded log messages exactly the same way as non-forwarded messages
197 except a forwarded message includes extra metadata about the remote interpreter. Log
198 forwarding is not currently enabled by default; to enable it set the
199 OBJECT_REMOTE_LOG_FORWARDING environment variable to 1. See L<Object::Remote::Logging::Router>.
201 =head1 EXPORTABLE SUBROUTINES
207 Returns an array reference that contains the ordered list of level names
208 with the lowest log level first and the highest log level last.
212 Returns the instance of L<Object::Remote::Logging::Router> that is in use. The router
213 instance is used in combination with L<Object::Remote::Logging::Logger> objects to
214 select then render and output log messages.
216 =item log_<level> and Dlog_<level>
218 These methods come direct from L<Log::Contextual>; see that documentation for a
219 complete reference. For each of the log level names there are subroutines with the log_
220 and Dlog_ prefix that will generate the log message. The first argument is a code block
221 that returns the log message contents and the optional further arguments are both passed
222 to the block as the argument list and returned from the log method as a list.
224 log_trace { "A fine log message $_[0] " } 'if I do say so myself';
225 %hash = Dlog_trace { "Very handy: $_" } ( foo => 'bar' );
227 =item logS_<level> and DlogS_<level>
229 Works just like log_ and Dlog_ except returns only the first argument as a scalar value.
231 my $beverage = log_info { "Customer ordered $_[0]" } 'Coffee';
237 Object::Remote uses an ordered list of log level names with the lowest level
238 first and the highest level last. The list of level names can be accessed via
239 the arg_levels method which is exportable to the consumer of this class. The log
246 As much information about operation as possible including multiple line dumps of
247 large content. Tripple verbose operation (-v -v -v).
251 Messages about operations that could hang as well as internal state changes,
252 results from method invocations, and information useful when looking for faults.
253 Double verbose operation (-v -v).
257 Additional optional messages to the user that can be enabled at their will. Single
258 verbose operation (-v).
262 Messages from normal operation that are intended to be displayed to the end
263 user if quiet operation is not indicated and more verbose operation is not
268 Something wasn't supposed to happen but did. Operation was not impacted but
269 otherwise the event is noteworthy. Single quiet operation (-q).
273 Something went wrong. Operation of the system may continue but some operation
274 has most definitely failed. Double quiet operation (-q -q).
278 Something went wrong and recovery is not possible. The system should stop operating
279 as soon as possible. Tripple quiet operation (-q -q -q).