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 ));
12 #exception log - log a message then die with that message
13 export_tag elog => ('____');
14 #fatal log - log a message then call exit(1)
15 export_tag flog => ('____');
18 our $Router_Instance ||= do {
19 require Object::Remote::Logging::Router;
20 Object::Remote::Logging::Router->new;
24 #log level descriptions
25 #info - standard log level - normal program output for the end user
26 #warn - output for program that is executing quietly
27 #error - output for program that is running more quietly
28 #fatal - it is not possible to continue execution; this level is as quiet as is possible
29 #verbose - output for program executing verbosely (-v)
30 #debug - output for program running more verbosely (-v -v)
31 #trace - output for program running extremely verbosely (-v -v -v)
33 #the order of the log levels is significant with the
34 #most verbose level being first in the list and the
35 #most quiet as the last item
36 return [qw( trace debug verbose info warn error fatal )];
40 my ($class, $importer, $spec) = @_;
41 my $router = $class->router;
49 $class->SUPER::before_import($importer, $spec);
51 my @levels = @{$class->arg_levels($spec->config->{levels})};
52 for my $level (@levels) {
53 if ($spec->config->{elog}) {
54 $spec->add_export("&Elog_$level", sub (&) {
55 my ($code, @args) = @_;
56 $router->handle_log_request({
58 package => scalar(caller),
62 #TODO this should get fed into a logger so it can be formatted
66 if ($spec->config->{flog}) {
67 #TODO that prototype isn't right
68 $spec->add_export("&Flog_$level", sub (&@) {
69 my ($code, $exit_value) = @_;
70 $exit_value = 1 unless defined $exit_value;
71 #don't let it going wrong stop us from calling exit()
72 eval { $router->handle_log_request({
74 package => scalar(caller),
78 warn "could not deliver log event during Flog_$level: $@" if $@;
79 eval { carp $code->() };
80 warn "could not emit warning during Flog_$level: $@" if $@;
87 sub _parse_selections {
88 my ($selections_string) = @_;
92 #" * -Object::Remote::Logging Foo::Bar::Baz "
93 foreach(split(/\s+/, $selections_string)) {
107 #this is invoked on all nodes
109 my $level = $ENV{OBJECT_REMOTE_LOG_LEVEL};
110 my $format = $ENV{OBJECT_REMOTE_LOG_FORMAT};
111 my $selections = $ENV{OBJECT_REMOTE_LOG_SELECTIONS};
112 my %controller_should_log;
114 return unless defined $level;
115 $format = "[%l %r] %s" unless defined $format;
116 $selections = __PACKAGE__ unless defined $selections;
117 %controller_should_log = _parse_selections($selections);
121 if (defined $Object::Remote::FatNode::REMOTE_NODE) {
122 #the connection id for the remote node comes in later
123 #as the controlling node inits remote logging
124 router()->_remote_metadata({ connection_id => undef });
128 my $logger = Object::Remote::Logging::Logger->new(
129 min_level => lc($level), format => $format,
130 level_names => Object::Remote::Logging::arg_levels(),
133 router()->connect(sub {
134 my $controller = $_[1]->{controller};
135 my $will_log = $controller_should_log{$controller};
137 $will_log = $controller_should_log{'*'} unless defined $will_log;
139 return unless $will_log;
140 #skip things from remote hosts because they log to STDERR
141 #when OBJECT_REMOTE_LOG_LEVEL is in effect
142 return if $_[1]->{remote}->{connection_id};
147 #this is invoked by the controlling node
149 sub init_remote_logging {
150 my ($self, %controller_info) = @_;
152 router()->_remote_metadata(\%controller_info);
153 #TODO having an instance of an object in the remote interpreter causes it to hang
154 #on exit intermitently or leave a zombie laying around frequently - not a bug limited
156 router()->_forward_destination($controller_info{router}) if $ENV{OBJECT_REMOTE_LOG_FORWARDING};
165 Object::Remote::Logging - Logging subsystem for Object::Remote
169 use Object::Remote::Logging qw( :log :dlog :elog :flog arg_levels router );
171 @levels = qw( trace debug verbose info warn error fatal );
172 @levels = arg_levels(); #same result
174 $ENV{OBJECT_REMOTE_LOG_LEVEL} = 'trace'; #or other level name
175 $ENV{OBJECT_REMOTE_LOG_FORMAT} = '%l %t: %p::%m %s'; #and more
176 $ENV{OBJECT_REMOTE_LOG_SELECTIONS} = 'Object::Remote::Logging Some::Other::Subclass';
177 $ENV{OBJECT_REMOTE_LOG_SELECTIONS} = '* -Object::Remote::Logging';
178 $ENV{OBJECT_REMOTE_LOG_FORWARDING} = 0 || 1; #default 0
180 log_info { 'Trace log event' };
181 Dlog_verbose { "Debug event with Data::Dumper::Concise: $_" } { foo => 'bar' };
182 Elog_error { 'Error event that calls die() with this string' };
183 Flog_fatal { 'Fatal event calls warn() then exit()' } 1;
187 This is the logging framework for Object::Remote implemented as a subclass of
188 L<Log::Contextual> with a slightly incompatible API. This system allows
189 developers using Object::Remote and end users of that software to control
190 Object::Remote logging so operation can be tracked if needed. This is also
191 the API used to generate log messages inside the Object::Remote source code.
193 The rest of the logging system comes from L<Object::Remote::Logging::Logger>
194 which implements log rendering and output and L<Object::Remote::Logging::Router>
195 which delivers log events to the loggers.
199 Object::Remote logging is not enabled by default. If you need to immediately start
200 debugging set the OBJECT_REMOTE_LOG_LEVEL environment variable to either 'trace'
201 or 'debug'. This will enable logging to STDERR on the local and all remote Perl
202 interpreters. By default STDERR for all remote interpreters is passed through
203 unmodified so this is sufficient to receive logs generated anywhere Object::Remote
206 Every time the local interpreter creates a new Object::Remote::Connection the connection
207 is given an id that is unique to that connection on the local interpreter. The connection
208 id and other metadata is available in the log output via a log format string that can
209 be set via the OBJECT_REMOTE_LOG_FORMAT environment variable. The format string and
210 available metadata is documented in L<Object::Remote::Logging::Logger>. Setting this
211 environment variable on the local interpreter will cause it to be propagated to the
212 remote interpreter so all logs will be formated the same way.
214 This class is designed so any module can create their own logging sub-class using it.
215 With out any additional configuration the consumers of this logging class will
216 automatically be enabled via OBJECT_REMOTE_LOG_LEVEL and formated with
217 OBJECT_REMOTE_LOG_FORMAT but those additional log messages are not sent to STDERR.
218 By setting the OBJECT_REMOTE_LOG_SELECTIONS environment variable to a list of
219 class names seperated by spaces then logs generated by packages that use those classes
220 will be sent to STDERR. If the asterisk character (*) is used in the place of a class
221 name then all class names will be selected by default instead of ignored. An individual
222 class name can be turned off by prefixing the name with a hypen character (-). This is
223 also a configuration item that is forwarded to the remote interpreters so all logging
226 Regardless of OBJECT_REMOTE_LOG_LEVEL the logging system is still active and loggers
227 can access the stream of log messages to format and output them. Internally
228 OBJECT_REMOTE_LOG_LEVEL causes an L<Object::Remote::Logging::Logger> to be built
229 and connected to the L<Object::Remote::Logging::Router> instance. It is also possible
230 to manually build a logger instance and connect it to the router. See the documentation
231 for the logger and router classes.
233 The logging system also supports a method of forwarding log messages from remote
234 interpreters to the local interpreter. Forwarded log messages are generated in the
235 remote interpreter and the logger for the message is invoked in the local interpreter.
236 Sub-classes of Object::Remote::Logging will have log messages forwarded automatically.
237 Loggers receive forwarded log messages exactly the same way as non-forwarded messages
238 except a forwarded message includes extra metadata about the remote interpreter. Log
239 forwarding is not currently enabled by default; to enable it set the
240 OBJECT_REMOTE_LOG_FORWARDING environment variable to 1. See L<Object::Remote::Logging::Router>.
242 =head1 EXPORTABLE SUBROUTINES
248 Returns an array reference that contains the ordered list of level names
249 with the lowest log level first and the highest log level last.
253 Returns the instance of L<Object::Remote::Logging::Router> that is in use. The router
254 instance is used in combination with L<Object::Remote::Logging::Logger> objects to
255 select then render and output log messages.
257 =item log_<level> and Dlog_<level>
259 These methods come direct from L<Log::Contextual>; see that documentation for a
260 complete reference. For each of the log level names there are subroutines with the log_
261 and Dlog_ prefix that will generate the log message. The first argument is a code block
262 that returns the log message contents and the optional further arguments are both passed
263 to the block as the argument list and returned from the log method as a list.
265 log_trace { "A fine log message $_[0] " } 'if I do say so myself';
266 %hash = Dlog_trace { "Very handy: $_" } ( foo => 'bar' );
268 =item logS_<level> and DlogS_<level>
270 Works just like log_ and Dlog_ except returns only the first argument as a scalar value.
272 my $beverage = log_info { "Customer ordered $_[0]" } 'Coffee';
276 Log an event and then generate an exception by calling die() with the log message.
278 Elog_error { "Could not open file: $!" };
282 Log the event, generate a warning with the log message, then call exit(). The exit
283 value will default to 1 or can be specified as an argument.
285 Flog_fatal { 'Could not lock resource' } 3;
291 Object::Remote uses an ordered list of log level names with the lowest level
292 first and the highest level last. The list of level names can be accessed via
293 the arg_levels method which is exportable to the consumer of this class. The log
300 As much information about operation as possible including multiple line dumps of
301 large content. Tripple verbose operation (-v -v -v).
305 Messages about operations that could hang as well as internal state changes,
306 results from method invocations, and information useful when looking for faults.
307 Double verbose operation (-v -v).
311 Additional optional messages to the user that can be enabled at their will. Single
312 verbose operation (-v).
316 Messages from normal operation that are intended to be displayed to the end
317 user if quiet operation is not indicated and more verbose operation is not
322 Something wasn't supposed to happen but did. Operation was not impacted but
323 otherwise the event is noteworthy. Single quiet operation (-q).
327 Something went wrong. Operation of the system may continue but some operation
328 has most definitely failed. Double quiet operation (-q -q).
332 Something went wrong and recovery is not possible. The system should stop operating
333 as soon as possible. Tripple quiet operation (-q -q -q).