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 $@;
81 sub _parse_selections {
82 my ($selections_string) = @_;
86 #" * -Object::Remote::Logging Foo::Bar::Baz "
87 foreach(split(/\s+/, $selections_string)) {
101 #this is invoked on all nodes
103 my $level = $ENV{OBJECT_REMOTE_LOG_LEVEL};
104 my $format = $ENV{OBJECT_REMOTE_LOG_FORMAT};
105 my $selections = $ENV{OBJECT_REMOTE_LOG_SELECTIONS};
106 my %controller_should_log;
108 return unless defined $level;
109 $format = "[%l %r] %s" unless defined $format;
110 $selections = __PACKAGE__ unless defined $selections;
111 %controller_should_log = _parse_selections($selections);
113 my $logger = Object::Remote::Logging::Logger->new(
114 min_level => lc($level), format => $format,
115 level_names => Object::Remote::Logging::arg_levels(),
118 router()->connect(sub {
119 my $controller = $_[1]->{controller};
120 my $will_log = $controller_should_log{$controller};
122 $will_log = $controller_should_log{'*'} unless defined $will_log;
124 return unless $will_log;
125 #skip things from remote hosts because they log to STDERR
126 #when OBJECT_REMOTE_LOG_LEVEL is in effect
127 return if $_[1]->{remote}->{connection_id};
132 #this is invoked by the controlling node
134 sub init_logging_forwarding {
135 my ($self, %controller_info) = @_;
137 router()->_remote_metadata({ connection_id => $controller_info{connection_id} });
138 #TODO having an instance of an object in the remote interpreter causes it to hang
139 #on exit intermitently or leave a zombie laying around frequently - not a bug limited
141 router()->_forward_destination($controller_info{router}) if $ENV{OBJECT_REMOTE_LOG_FORWARDING};
150 Object::Remote::Logging - Logging subsystem for Object::Remote
154 use Object::Remote::Logging qw( :log :dlog :elog :flog arg_levels router );
156 @levels = qw( trace debug verbose info warn error fatal );
157 @levels = arg_levels(); #same result
159 $ENV{OBJECT_REMOTE_LOG_LEVEL} = 'trace'; #or other level name
160 $ENV{OBJECT_REMOTE_LOG_FORMAT} = '%l %t: %p::%m %s'; #and more
161 $ENV{OBJECT_REMOTE_LOG_SELECTIONS} = 'Object::Remote::Logging Some::Other::Subclass';
162 $ENV{OBJECT_REMOTE_LOG_SELECTIONS} = '* -Object::Remote::Logging';
163 $ENV{OBJECT_REMOTE_LOG_FORWARDING} = 0 || 1; #default 0
165 log_info { 'Trace log event' };
166 Dlog_verbose { "Debug event with Data::Dumper::Concise: $_" } { foo => 'bar' };
167 Elog_error { 'Error event that calls die() with this string' };
168 Flog_fatal { 'Fatal event calls warn() then exit()' } 1;
172 This is the logging framework for Object::Remote implemented as a subclass of
173 L<Log::Contextual> with a slightly incompatible API. This system allows
174 developers using Object::Remote and end users of that software to control
175 Object::Remote logging so operation can be tracked if needed. This is also
176 the API used to generate log messages inside the Object::Remote source code.
178 The rest of the logging system comes from L<Object::Remote::Logging::Logger>
179 which implements log rendering and output and L<Object::Remote::Logging::Router>
180 which delivers log events to the loggers.
184 Object::Remote logging is not enabled by default. If you need to immediately start
185 debugging set the OBJECT_REMOTE_LOG_LEVEL environment variable to either 'trace'
186 or 'debug'. This will enable logging to STDERR on the local and all remote Perl
187 interpreters. By default STDERR for all remote interpreters is passed through
188 unmodified so this is sufficient to receive logs generated anywhere Object::Remote
191 Every time the local interpreter creates a new Object::Remote::Connection the connection
192 is given an id that is unique to that connection on the local interpreter. The connection
193 id and other metadata is available in the log output via a log format string that can
194 be set via the OBJECT_REMOTE_LOG_FORMAT environment variable. The format string and
195 available metadata is documented in L<Object::Remote::Logging::Logger>. Setting this
196 environment variable on the local interpreter will cause it to be propagated to the
197 remote interpreter so all logs will be formated the same way.
199 This class is designed so any module can create their own logging sub-class using it.
200 With out any additional configuration the consumers of this logging class will
201 automatically be enabled via OBJECT_REMOTE_LOG_LEVEL and formated with
202 OBJECT_REMOTE_LOG_FORMAT but those additional log messages are not sent to STDERR.
203 By setting the OBJECT_REMOTE_LOG_SELECTIONS environment variable to a list of
204 class names seperated by spaces then logs generated by packages that use those classes
205 will be sent to STDERR. If the asterisk character (*) is used in the place of a class
206 name then all class names will be selected by default instead of ignored. An individual
207 class name can be turned off by prefixing the name with a hypen character (-). This is
208 also a configuration item that is forwarded to the remote interpreters so all logging
211 Regardless of OBJECT_REMOTE_LOG_LEVEL the logging system is still active and loggers
212 can access the stream of log messages to format and output them. Internally
213 OBJECT_REMOTE_LOG_LEVEL causes an L<Object::Remote::Logging::Logger> to be built
214 and connected to the L<Object::Remote::Logging::Router> instance. It is also possible
215 to manually build a logger instance and connect it to the router. See the documentation
216 for the logger and router classes.
218 The logging system also supports a method of forwarding log messages from remote
219 interpreters to the local interpreter. Forwarded log messages are generated in the
220 remote interpreter and the logger for the message is invoked in the local interpreter.
221 Sub-classes of Object::Remote::Logging will have log messages forwarded automatically.
222 Loggers receive forwarded log messages exactly the same way as non-forwarded messages
223 except a forwarded message includes extra metadata about the remote interpreter. Log
224 forwarding is not currently enabled by default; to enable it set the
225 OBJECT_REMOTE_LOG_FORWARDING environment variable to 1. See L<Object::Remote::Logging::Router>.
227 =head1 EXPORTABLE SUBROUTINES
233 Returns an array reference that contains the ordered list of level names
234 with the lowest log level first and the highest log level last.
238 Returns the instance of L<Object::Remote::Logging::Router> that is in use. The router
239 instance is used in combination with L<Object::Remote::Logging::Logger> objects to
240 select then render and output log messages.
242 =item log_<level> and Dlog_<level>
244 These methods come direct from L<Log::Contextual>; see that documentation for a
245 complete reference. For each of the log level names there are subroutines with the log_
246 and Dlog_ prefix that will generate the log message. The first argument is a code block
247 that returns the log message contents and the optional further arguments are both passed
248 to the block as the argument list and returned from the log method as a list.
250 log_trace { "A fine log message $_[0] " } 'if I do say so myself';
251 %hash = Dlog_trace { "Very handy: $_" } ( foo => 'bar' );
253 =item logS_<level> and DlogS_<level>
255 Works just like log_ and Dlog_ except returns only the first argument as a scalar value.
257 my $beverage = log_info { "Customer ordered $_[0]" } 'Coffee';
261 Log an event and then generate an exception by calling die() with the log message.
263 Elog_error { "Could not open file: $!" };
267 Log the event, generate a warning with the log message, then call exit(). The exit
268 value will default to 1 or can be specified as an argument.
270 Flog_fatal { 'Could not lock resource' } 3;
276 Object::Remote uses an ordered list of log level names with the lowest level
277 first and the highest level last. The list of level names can be accessed via
278 the arg_levels method which is exportable to the consumer of this class. The log
285 As much information about operation as possible including multiple line dumps of
286 large content. Tripple verbose operation (-v -v -v).
290 Messages about operations that could hang as well as internal state changes,
291 results from method invocations, and information useful when looking for faults.
292 Double verbose operation (-v -v).
296 Additional optional messages to the user that can be enabled at their will. Single
297 verbose operation (-v).
301 Messages from normal operation that are intended to be displayed to the end
302 user if quiet operation is not indicated and more verbose operation is not
307 Something wasn't supposed to happen but did. Operation was not impacted but
308 otherwise the event is noteworthy. Single quiet operation (-q).
312 Something went wrong. Operation of the system may continue but some operation
313 has most definitely failed. Double quiet operation (-q -q).
317 Something went wrong and recovery is not possible. The system should stop operating
318 as soon as possible. Tripple quiet operation (-q -q -q).