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 defined $@;
73 eval { carp $code->() };
74 warn "could not emit warning during Flog_$level: $@" if defined $@;
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;
88 return unless defined $level;
89 $format = "[%l %r] %s" unless defined $format;
90 $selections = __PACKAGE__ unless defined $selections;
91 %controller_should_log = map { $_ => 1 } split(' ', $selections);
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 return unless $controller_should_log{'*'} || $controller_should_log{$controller};
101 #skip things from remote hosts because they log to STDERR
102 #when OBJECT_REMOTE_LOG_LEVEL is in effect
103 return if $_[1]->{remote}->{connection_id};
108 #this is invoked by the controlling node
110 sub init_logging_forwarding {
111 my ($self, %controller_info) = @_;
113 router()->_remote_metadata({ connection_id => $controller_info{connection_id} });
114 router()->_forward_destination($controller_info{router}) if $ENV{OBJECT_REMOTE_LOG_FORWARDING};
123 Object::Remote::Logging - Logging subsystem for Object::Remote
127 use Object::Remote::Logging qw( :log :dlog :elog :flog arg_levels router );
129 @levels = qw( trace debug verbose info warn error fatal );
130 @levels = arg_levels(); #same result
132 $ENV{OBJECT_REMOTE_LOG_LEVEL} = 'trace'; #or other level name
133 $ENV{OBJECT_REMOTE_LOG_FORMAT} = '%l %t: %p::%m %s'; #and more
134 $ENV{OBJECT_REMOTE_LOG_SELECTIONS} = 'Object::Remote::Logging Some::Other::Subclass';
135 $ENV{OBJECT_REMOTE_LOG_FORWARDING} = 0 || 1; #default 0
137 log_info { 'Trace log event' };
138 Dlog_verbose { "Debug event with Data::Dumper::Concise: $_" } { foo => 'bar' };
139 Elog_error { 'Error event that calls die() with this string' };
140 Flog_fatal { 'Fatal event calls warn() then exit()' } 1;
144 This is the logging framework for Object::Remote implemented as a subclass of
145 L<Log::Contextual> with a slightly incompatible API. This system allows
146 developers using Object::Remote and end users of that software to control
147 Object::Remote logging so operation can be tracked if needed. This is also
148 the API used to generate log messages inside the Object::Remote source code.
150 The rest of the logging system comes from L<Object::Remote::Logging::Logger>
151 which implements log rendering and output and L<Object::Remote::Logging::Router>
152 which delivers log events to the loggers.
156 Object::Remote logging is not enabled by default. If you need to immediately start
157 debugging set the OBJECT_REMOTE_LOG_LEVEL environment variable to either 'trace'
158 or 'debug'. This will enable logging to STDERR on the local and all remote Perl
159 interpreters. By default STDERR for all remote interpreters is passed through
160 unmodified so this is sufficient to receive logs generated anywhere Object::Remote
163 Every time the local interpreter creates a new Object::Remote::Connection the connection
164 is given an id that is unique to that connection on the local interpreter. The connection
165 id and other metadata is available in the log output via a log format string that can
166 be set via the OBJECT_REMOTE_LOG_FORMAT environment variable. The format string and
167 available metadata is documented in L<Object::Remote::Logging::Logger>. Setting this
168 environment variable on the local interpreter will cause it to be propagated to the
169 remote interpreter so all logs will be formated the same way.
171 This class is designed so any module can create their own logging sub-class using it.
172 With out any additional configuration the consumers of this logging class will
173 automatically be enabled via OBJECT_REMOTE_LOG_LEVEL and formated with
174 OBJECT_REMOTE_LOG_FORMAT but those additional log messages are not sent to STDERR.
175 By setting the OBJECT_REMOTE_LOG_SELECTIONS environment variable to a list of
176 class names seperated by spaces then logs generated by packages that use those classes
177 will be sent to STDERR. This is also a configuration item that is forwarded to the
178 remote interpreters so all logging is consistent.
180 Regardless of OBJECT_REMOTE_LOG_LEVEL the logging system is still active and loggers
181 can access the stream of log messages to format and output them. Internally
182 OBJECT_REMOTE_LOG_LEVEL causes an L<Object::Remote::Logging::Logger> to be built
183 and connected to the L<Object::Remote::Logging::Router> instance. It is also possible
184 to manually build a logger instance and connect it to the router. See the documentation
185 for the logger and router classes.
187 The logging system also supports a method of forwarding log messages from remote
188 interpreters to the local interpreter. Forwarded log messages are generated in the
189 remote interpreter and the logger for the message is invoked in the local interpreter.
190 Sub-classes of Object::Remote::Logging will have log messages forwarded automatically.
191 Loggers receive forwarded log messages exactly the same way as non-forwarded messages
192 except a forwarded message includes extra metadata about the remote interpreter. Log
193 forwarding is not currently enabled by default; to enable it set the
194 OBJECT_REMOTE_LOG_FORWARDING environment variable to 1. See L<Object::Remote::Logging::Router>.
196 =head1 EXPORTABLE SUBROUTINES
202 Returns an array reference that contains the ordered list of level names
203 with the lowest log level first and the highest log level last.
207 Returns the instance of L<Object::Remote::Logging::Router> that is in use. The router
208 instance is used in combination with L<Object::Remote::Logging::Logger> objects to
209 select then render and output log messages.
211 =item log_<level> and Dlog_<level>
213 These methods come direct from L<Log::Contextual>; see that documentation for a
214 complete reference. For each of the log level names there are subroutines with the log_
215 and Dlog_ prefix that will generate the log message. The first argument is a code block
216 that returns the log message contents and the optional further arguments are both passed
217 to the block as the argument list and returned from the log method as a list.
219 log_trace { "A fine log message $_[0] " } 'if I do say so myself';
220 %hash = Dlog_trace { "Very handy: $_" } ( foo => 'bar' );
222 =item logS_<level> and DlogS_<level>
224 Works just like log_ and Dlog_ except returns only the first argument as a scalar value.
226 my $beverage = log_info { "Customer ordered $_[0]" } 'Coffee';
230 Log an event and then generate an exception by calling die() with the log message.
232 Elog_error { "Could not open file: $!" };
236 Log the event, generate a warning with the log message, then call exit(). The exit
237 value will default to 1 or can be specified as an argument.
239 Flog_fatal { 'Could not lock resource' } 3;
245 Object::Remote uses an ordered list of log level names with the minimum level
246 first and the maximum level last. The list of level names can be accessed via
247 the arg_levels method which is exportable to the consumer of this class. The log
254 As much information about operation as possible including multiple line dumps of
255 large content. Tripple verbose operation (-v -v -v).
259 Messages about operations that could hang as well as internal state changes,
260 results from method invocations, and information useful when looking for faults.
261 Double verbose operation (-v -v).
265 Additional optional messages to the user that can be enabled at their will. Single
266 verbose operation (-v).
270 Messages from normal operation that are intended to be displayed to the end
271 user if quiet operation is not indicated and more verbose operation is not
276 Something wasn't supposed to happen but did. Operation was not impacted but
277 otherwise the event is noteworthy. Single quiet operation (-q).
281 Something went wrong. Operation of the system may continue but some operation
282 has most definitely failed. Double quiet operation (-q -q).
286 Something went wrong and recovery is not possible. The system should stop operating
287 as soon as possible. Tripple quiet operation (-q -q -q).