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;
43 $class->SUPER::before_import($importer, $spec);
45 my @levels = @{$class->arg_levels($spec->config->{levels})};
46 for my $level (@levels) {
47 if ($spec->config->{elog}) {
48 $spec->add_export("&Elog_$level", sub (&) {
49 my ($code, @args) = @_;
50 $router->handle_log_request({
52 package => scalar(caller),
56 #TODO this should get fed into a logger so it can be formatted
60 if ($spec->config->{flog}) {
61 #TODO that prototype isn't right
62 $spec->add_export("&Flog_$level", sub (&@) {
63 my ($code, $exit_value) = @_;
64 $exit_value = 1 unless defined $exit_value;
65 #don't let it going wrong stop us from calling exit()
66 eval { $router->handle_log_request({
68 package => scalar(caller),
72 warn "could not deliver log event during Flog_$level: $@" if $@;
73 eval { carp $code->() };
74 warn "could not emit warning during Flog_$level: $@" if $@;
81 #this is invoked on all nodes
83 my $level = $ENV{OBJECT_REMOTE_LOG_LEVEL};
84 my $format = $ENV{OBJECT_REMOTE_LOG_FORMAT};
85 my $selections = $ENV{OBJECT_REMOTE_LOG_SELECTIONS};
86 my %controller_should_log;
89 require Log::Any::Adapter;
90 require Object::Remote::Logging::LogAnyInjector;
91 Log::Any::Adapter->set('+Object::Remote::Logging::LogAnyInjector');
94 return unless defined $level;
95 $format = "[%l %r] %s" unless defined $format;
96 $selections = __PACKAGE__ unless defined $selections;
97 %controller_should_log = map { $_ => 1 } split(' ', $selections);
99 my $logger = Object::Remote::Logging::Logger->new(
100 min_level => lc($level), format => $format,
101 level_names => Object::Remote::Logging::arg_levels(),
104 router()->connect(sub {
105 my $controller = $_[1]->{controller};
106 return unless $controller_should_log{'*'} || $controller_should_log{$controller};
107 #skip things from remote hosts because they log to STDERR
108 #when OBJECT_REMOTE_LOG_LEVEL is in effect
109 return if $_[1]->{remote}->{connection_id};
114 #this is invoked by the controlling node
116 sub init_logging_forwarding {
117 my ($self, %controller_info) = @_;
119 router()->_remote_metadata({ connection_id => $controller_info{connection_id} });
120 router()->_forward_destination($controller_info{router}) if $ENV{OBJECT_REMOTE_LOG_FORWARDING};
129 Object::Remote::Logging - Logging subsystem for Object::Remote
133 use Object::Remote::Logging qw( :log :dlog :elog :flog arg_levels router );
135 @levels = qw( trace debug verbose info warn error fatal );
136 @levels = arg_levels(); #same result
138 $ENV{OBJECT_REMOTE_LOG_LEVEL} = 'trace'; #or other level name
139 $ENV{OBJECT_REMOTE_LOG_FORMAT} = '%l %t: %p::%m %s'; #and more
140 $ENV{OBJECT_REMOTE_LOG_SELECTIONS} = 'Object::Remote::Logging Some::Other::Subclass';
141 $ENV{OBJECT_REMOTE_LOG_FORWARDING} = 0 || 1; #default 0
143 log_info { 'Trace log event' };
144 Dlog_verbose { "Debug event with Data::Dumper::Concise: $_" } { foo => 'bar' };
145 Elog_error { 'Error event that calls die() with this string' };
146 Flog_fatal { 'Fatal event calls warn() then exit()' } 1;
150 This is the logging framework for Object::Remote implemented as a subclass of
151 L<Log::Contextual> with a slightly incompatible API. This system allows
152 developers using Object::Remote and end users of that software to control
153 Object::Remote logging so operation can be tracked if needed. This is also
154 the API used to generate log messages inside the Object::Remote source code.
156 The rest of the logging system comes from L<Object::Remote::Logging::Logger>
157 which implements log rendering and output and L<Object::Remote::Logging::Router>
158 which delivers log events to the loggers.
162 Object::Remote logging is not enabled by default. If you need to immediately start
163 debugging set the OBJECT_REMOTE_LOG_LEVEL environment variable to either 'trace'
164 or 'debug'. This will enable logging to STDERR on the local and all remote Perl
165 interpreters. By default STDERR for all remote interpreters is passed through
166 unmodified so this is sufficient to receive logs generated anywhere Object::Remote
169 Every time the local interpreter creates a new Object::Remote::Connection the connection
170 is given an id that is unique to that connection on the local interpreter. The connection
171 id and other metadata is available in the log output via a log format string that can
172 be set via the OBJECT_REMOTE_LOG_FORMAT environment variable. The format string and
173 available metadata is documented in L<Object::Remote::Logging::Logger>. Setting this
174 environment variable on the local interpreter will cause it to be propagated to the
175 remote interpreter so all logs will be formated the same way.
177 This class is designed so any module can create their own logging sub-class using it.
178 With out any additional configuration the consumers of this logging class will
179 automatically be enabled via OBJECT_REMOTE_LOG_LEVEL and formated with
180 OBJECT_REMOTE_LOG_FORMAT but those additional log messages are not sent to STDERR.
181 By setting the OBJECT_REMOTE_LOG_SELECTIONS environment variable to a list of
182 class names seperated by spaces then logs generated by packages that use those classes
183 will be sent to STDERR. This is also a configuration item that is forwarded to the
184 remote interpreters so all logging is consistent.
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 not currently enabled by default; to enable it set the
200 OBJECT_REMOTE_LOG_FORWARDING environment variable to 1. 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 = log_info { "Customer ordered $_[0]" } 'Coffee';
236 Log an event and then generate an exception by calling die() with the log message.
238 Elog_error { "Could not open file: $!" };
242 Log the event, generate a warning with the log message, then call exit(). The exit
243 value will default to 1 or can be specified as an argument.
245 Flog_fatal { 'Could not lock resource' } 3;
251 Object::Remote uses an ordered list of log level names with the minimum level
252 first and the maximum level last. The list of level names can be accessed via
253 the arg_levels method which is exportable to the consumer of this class. The log
260 As much information about operation as possible including multiple line dumps of
261 large content. Tripple verbose operation (-v -v -v).
265 Messages about operations that could hang as well as internal state changes,
266 results from method invocations, and information useful when looking for faults.
267 Double verbose operation (-v -v).
271 Additional optional messages to the user that can be enabled at their will. Single
272 verbose operation (-v).
276 Messages from normal operation that are intended to be displayed to the end
277 user if quiet operation is not indicated and more verbose operation is not
282 Something wasn't supposed to happen but did. Operation was not impacted but
283 otherwise the event is noteworthy. Single quiet operation (-q).
287 Something went wrong. Operation of the system may continue but some operation
288 has most definitely failed. Double quiet operation (-q -q).
292 Something went wrong and recovery is not possible. The system should stop operating
293 as soon as possible. Tripple quiet operation (-q -q -q).