logger class now supports instances with distinct log levels via autoload methods
[scpubgit/Object-Remote.git] / lib / Object / Remote / Logging.pm
5e2b2229 1package Object::Remote::Logging;
4e446335 3use Moo;
4use Scalar::Util qw(blessed);
5use Object::Remote::Logging::Logger;
f4a85080 6use Exporter::Declare;
663fb34f 7use Carp qw(carp croak);
5e2b2229 8
4e446335 9extends 'Log::Contextual';
5e2b2229 10
663fb34f 11exports(qw( ____ router arg_levels ));
12#exception log - log a message then die with that message
13export_tag elog => ('____');
14#fatal log - log a message then call exit(1)
15export_tag flog => ('____');
f4a85080 16
4e446335 17sub router {
c0b2df05 18 our $Router_Instance ||= do {
19 require Object::Remote::Logging::Router;
20 Object::Remote::Logging::Router->new;
21 }
4e446335 22}
5e2b2229 23
9de32e1d 24#log level descriptions
25#info - standard log level - normal program output for the end user
26#warn - output for program that is executing quietly
27#error - output for program that is running more quietly
28#fatal - it is not possible to continue execution; this level is as quiet as is possible
29#verbose - output for program executing verbosely (-v)
30#debug - output for program running more verbosely (-v -v)
31#trace - output for program running extremely verbosely (-v -v -v)
4e446335 32sub arg_levels {
9de32e1d 33 #the order of the log levels is significant with the
34 #most verbose level being first in the list and the
35 #most quiet as the last item
36 return [qw( trace debug verbose info warn error fatal )];
4a9fa1a5 37}
5e2b2229 38
663fb34f 39sub before_import {
40 my ($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({
51 controller => $class,
52 package => scalar(caller),
53 caller_level => 1,
54 level => $level,
55 }, $code);
56 #TODO this should get fed into a logger so it can be formatted
57 croak $code->();
58 });
59 }
60 if ($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;
455d031c 65 #don't let it going wrong stop us from calling exit()
66 eval { $router->handle_log_request({
663fb34f 67 controller => $class,
68 package => scalar(caller),
69 caller_level => 1,
70 level => $level,
455d031c 71 }, $code) };
72 warn "could not deliver log event during Flog_$level: $@" if defined $@;
d672a9bf 73 eval { carp $code->() };
455d031c 74 warn "could not emit warning during Flog_$level: $@" if defined $@;
663fb34f 75 exit($exit_value);
76 });
77 }
78 }
4e446335 81#this is invoked on all nodes
4a9fa1a5 82sub init_logging {
c0b2df05 83 my $level = $ENV{OBJECT_REMOTE_LOG_LEVEL};
0fe333eb 84 my $format = $ENV{OBJECT_REMOTE_LOG_FORMAT};
eb49c7df 85 my $selections = $ENV{OBJECT_REMOTE_LOG_SELECTIONS};
86 my %controller_should_log;
c0b2df05 88 return unless defined $level;
0fe333eb 89 $format = "[%l %r] %s" unless defined $format;
eb49c7df 90 $selections = __PACKAGE__ unless defined $selections;
91 %controller_should_log = map { $_ => 1 } split(' ', $selections);
c0b2df05 93 my $logger = Object::Remote::Logging::Logger->new(
0fe333eb 94 min_level => lc($level), format => $format,
c0b2df05 95 level_names => Object::Remote::Logging::arg_levels(),
96 );
c0b2df05 98 router()->connect(sub {
eb49c7df 99 my $controller = $_[1]->{controller};
455d031c 100 return unless $controller_should_log{'*'} || $controller_should_log{$controller};
c0b2df05 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};
104 $logger
105 });
4a9fa1a5 106}
4e446335 108#this is invoked by the controlling node
109#on the remote nodes
4a9fa1a5 110sub init_logging_forwarding {
4e446335 111 my ($self, %controller_info) = @_;
113 router()->_remote_metadata({ connection_id => $controller_info{connection_id} });
466ee2c4 114 router()->_forward_destination($controller_info{router}) if $ENV{OBJECT_REMOTE_LOG_FORWARDING};
4a9fa1a5 115}
5e2b2229 116
455d031c 118
d672a9bf 119__END__
121=head1 NAME
123Object::Remote::Logging - Logging subsystem for Object::Remote
125=head1 SYNOPSIS
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
d672a9bf 134 $ENV{OBJECT_REMOTE_LOG_SELECTIONS} = 'Object::Remote::Logging Some::Other::Subclass';
455d031c 135 $ENV{OBJECT_REMOTE_LOG_FORWARDING} = 0 || 1; #default 0
d672a9bf 136
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;
144This is the logging framework for Object::Remote implemented as a subclass of
145L<Log::Contextual> with a slightly incompatible API. This system allows
146developers using Object::Remote and end users of that software to control
147Object::Remote logging so operation can be tracked if needed. This is also
148the API used to generate log messages inside the Object::Remote source code.
150The rest of the logging system comes from L<Object::Remote::Logging::Logger>
151which implements log rendering and output and L<Object::Remote::Logging::Router>
152which delivers log events to the loggers.
455d031c 154=head1 USAGE
156Object::Remote logging is not enabled by default. If you need to immediately start
157debugging set the OBJECT_REMOTE_LOG_LEVEL environment variable to either 'trace'
158or 'debug'. This will enable logging to STDERR on the local and all remote Perl
159interpreters. By default STDERR for all remote interpreters is passed through
160unmodified so this is sufficient to receive logs generated anywhere Object::Remote
161is running.
163Every time the local interpreter creates a new Object::Remote::Connection the connection
164is given an id that is unique to that connection on the local interpreter. The connection
165id and other metadata is available in the log output via a log format string that can
166be set via the OBJECT_REMOTE_LOG_FORMAT environment variable. The format string and
167available metadata is documented in L<Object::Remote::Logging::Logger>. Setting this
168environment variable on the local interpreter will cause it to be propagated to the
169remote interpreter so all logs will be formated the same way.
171This class is designed so any module can create their own logging sub-class using it.
f21127fd 172With out any additional configuration the consumers of this logging class will
173automatically be enabled via OBJECT_REMOTE_LOG_LEVEL and formated with
174OBJECT_REMOTE_LOG_FORMAT but those additional log messages are not sent to STDERR.
175By setting the OBJECT_REMOTE_LOG_SELECTIONS environment variable to a list of
176class names seperated by spaces then logs generated by packages that use those classes
177will be sent to STDERR. This is also a configuration item that is forwarded to the
178remote interpreters so all logging is consistent.
455d031c 179
180Regardless of OBJECT_REMOTE_LOG_LEVEL the logging system is still active and loggers
181can access the stream of log messages to format and output them. Internally
182OBJECT_REMOTE_LOG_LEVEL causes an L<Object::Remote::Logging::Logger> to be built
183and connected to the L<Object::Remote::Logging::Router> instance. It is also possible
184to manually build a logger instance and connect it to the router. See the documentation
f21127fd 185for the logger and router classes.
455d031c 186
187The logging system also supports a method of forwarding log messages from remote
188interpreters to the local interpreter. Forwarded log messages are generated in the
189remote interpreter and the logger for the message is invoked in the local interpreter.
190Sub-classes of Object::Remote::Logging will have log messages forwarded automatically.
191Loggers receive forwarded log messages exactly the same way as non-forwarded messages
192except a forwarded message includes extra metadata about the remote interpreter. Log
193forwarding is not currently enabled by default; to enable it set the
194OBJECT_REMOTE_LOG_FORWARDING environment variable to 1. See L<Object::Remote::Logging::Router>.
198=over 4
200=item arg_levels
202Returns an array reference that contains the ordered list of level names
203with the lowest log level first and the highest log level last.
205=item router
207Returns the instance of L<Object::Remote::Logging::Router> that is in use. The router
208instance is used in combination with L<Object::Remote::Logging::Logger> objects to
209select then render and output log messages.
211=item log_<level> and Dlog_<level>
213These methods come direct from L<Log::Contextual>; see that documentation for a
214complete reference. For each of the log level names there are subroutines with the log_
215and Dlog_ prefix that will generate the log message. The first argument is a code block
216that returns the log message contents and the optional further arguments are both passed
217to 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';
455d031c 220 %hash = Dlog_trace { "Very handy: $_" } ( foo => 'bar' );
d672a9bf 221
222=item logS_<level> and DlogS_<level>
224Works just like log_ and Dlog_ except returns only the first argument as a scalar value.
226 my $beverage = log_info { "Customer ordered $_[0]" } 'Coffee';
228=item Elog_<level>
230Log an event and then generate an exception by calling die() with the log message.
232 Elog_error { "Could not open file: $!" };
234=item Flog_<level>
236Log the event, generate a warning with the log message, then call exit(). The exit
237value will default to 1 or can be specified as an argument.
239 Flog_fatal { 'Could not lock resource' } 3;
243=head1 LEVEL NAMES
245Object::Remote uses an ordered list of log level names with the minimum level
246first and the maximum level last. The list of level names can be accessed via
247the arg_levels method which is exportable to the consumer of this class. The log
248level names are:
250=over 4
252=item trace
254As much information about operation as possible including multiple line dumps of
255large content. Tripple verbose operation (-v -v -v).
257=item debug
259Messages about operations that could hang as well as internal state changes,
260results from method invocations, and information useful when looking for faults.
261Double verbose operation (-v -v).
263=item verbose
265Additional optional messages to the user that can be enabled at their will. Single
266verbose operation (-v).
268=item info
270Messages from normal operation that are intended to be displayed to the end
271user if quiet operation is not indicated and more verbose operation is not
272in effect.
274=item warn
276Something wasn't supposed to happen but did. Operation was not impacted but
277otherwise the event is noteworthy. Single quiet operation (-q).
279=item error
281Something went wrong. Operation of the system may continue but some operation
282has most definitely failed. Double quiet operation (-q -q).
284=item fatal
286Something went wrong and recovery is not possible. The system should stop operating
287as soon as possible. Tripple quiet operation (-q -q -q).