Log::Any can inject messages into log router and acts as full class citizen in loggin...
[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 }, $code) };
5cd5276e 72 warn "could not deliver log event during Flog_$level: $@" if $@;
d672a9bf 73 eval { carp $code->() };
5cd5276e 74 warn "could not emit warning during Flog_$level: $@" if $@;
663fb34f 75 exit($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;
5cd5276e 87
88 eval {
89 require Log::Any::Adapter;
90 require Object::Remote::Logging::LogAnyInjector;
91 Log::Any::Adapter->set('+Object::Remote::Logging::LogAnyInjector');
92 };
c0b2df05 94 return unless defined $level;
0fe333eb 95 $format = "[%l %r] %s" unless defined $format;
eb49c7df 96 $selections = __PACKAGE__ unless defined $selections;
97 %controller_should_log = map { $_ => 1 } split(' ', $selections);
c0b2df05 99 my $logger = Object::Remote::Logging::Logger->new(
0fe333eb 100 min_level => lc($level), format => $format,
c0b2df05 101 level_names => Object::Remote::Logging::arg_levels(),
102 );
c0b2df05 104 router()->connect(sub {
eb49c7df 105 my $controller = $_[1]->{controller};
455d031c 106 return unless $controller_should_log{'*'} || $controller_should_log{$controller};
c0b2df05 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};
110 $logger
111 });
4a9fa1a5 112}
4e446335 114#this is invoked by the controlling node
115#on the remote nodes
4a9fa1a5 116sub init_logging_forwarding {
4e446335 117 my ($self, %controller_info) = @_;
119 router()->_remote_metadata({ connection_id => $controller_info{connection_id} });
466ee2c4 120 router()->_forward_destination($controller_info{router}) if $ENV{OBJECT_REMOTE_LOG_FORWARDING};
4a9fa1a5 121}
5e2b2229 122
455d031c 124
d672a9bf 125__END__
127=head1 NAME
129Object::Remote::Logging - Logging subsystem for Object::Remote
131=head1 SYNOPSIS
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
d672a9bf 140 $ENV{OBJECT_REMOTE_LOG_SELECTIONS} = 'Object::Remote::Logging Some::Other::Subclass';
455d031c 141 $ENV{OBJECT_REMOTE_LOG_FORWARDING} = 0 || 1; #default 0
d672a9bf 142
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;
150This is the logging framework for Object::Remote implemented as a subclass of
151L<Log::Contextual> with a slightly incompatible API. This system allows
152developers using Object::Remote and end users of that software to control
153Object::Remote logging so operation can be tracked if needed. This is also
154the API used to generate log messages inside the Object::Remote source code.
156The rest of the logging system comes from L<Object::Remote::Logging::Logger>
157which implements log rendering and output and L<Object::Remote::Logging::Router>
158which delivers log events to the loggers.
455d031c 160=head1 USAGE
162Object::Remote logging is not enabled by default. If you need to immediately start
163debugging set the OBJECT_REMOTE_LOG_LEVEL environment variable to either 'trace'
164or 'debug'. This will enable logging to STDERR on the local and all remote Perl
165interpreters. By default STDERR for all remote interpreters is passed through
166unmodified so this is sufficient to receive logs generated anywhere Object::Remote
167is running.
169Every time the local interpreter creates a new Object::Remote::Connection the connection
170is given an id that is unique to that connection on the local interpreter. The connection
171id and other metadata is available in the log output via a log format string that can
172be set via the OBJECT_REMOTE_LOG_FORMAT environment variable. The format string and
173available metadata is documented in L<Object::Remote::Logging::Logger>. Setting this
174environment variable on the local interpreter will cause it to be propagated to the
175remote interpreter so all logs will be formated the same way.
177This class is designed so any module can create their own logging sub-class using it.
f21127fd 178With out any additional configuration the consumers of this logging class will
179automatically be enabled via OBJECT_REMOTE_LOG_LEVEL and formated with
180OBJECT_REMOTE_LOG_FORMAT but those additional log messages are not sent to STDERR.
181By setting the OBJECT_REMOTE_LOG_SELECTIONS environment variable to a list of
182class names seperated by spaces then logs generated by packages that use those classes
183will be sent to STDERR. This is also a configuration item that is forwarded to the
184remote interpreters so all logging is consistent.
455d031c 185
186Regardless of OBJECT_REMOTE_LOG_LEVEL the logging system is still active and loggers
187can access the stream of log messages to format and output them. Internally
188OBJECT_REMOTE_LOG_LEVEL causes an L<Object::Remote::Logging::Logger> to be built
189and connected to the L<Object::Remote::Logging::Router> instance. It is also possible
190to manually build a logger instance and connect it to the router. See the documentation
f21127fd 191for the logger and router classes.
455d031c 192
193The logging system also supports a method of forwarding log messages from remote
194interpreters to the local interpreter. Forwarded log messages are generated in the
195remote interpreter and the logger for the message is invoked in the local interpreter.
196Sub-classes of Object::Remote::Logging will have log messages forwarded automatically.
197Loggers receive forwarded log messages exactly the same way as non-forwarded messages
198except a forwarded message includes extra metadata about the remote interpreter. Log
199forwarding is not currently enabled by default; to enable it set the
200OBJECT_REMOTE_LOG_FORWARDING environment variable to 1. See L<Object::Remote::Logging::Router>.
204=over 4
206=item arg_levels
208Returns an array reference that contains the ordered list of level names
209with the lowest log level first and the highest log level last.
211=item router
213Returns the instance of L<Object::Remote::Logging::Router> that is in use. The router
214instance is used in combination with L<Object::Remote::Logging::Logger> objects to
215select then render and output log messages.
217=item log_<level> and Dlog_<level>
219These methods come direct from L<Log::Contextual>; see that documentation for a
220complete reference. For each of the log level names there are subroutines with the log_
221and Dlog_ prefix that will generate the log message. The first argument is a code block
222that returns the log message contents and the optional further arguments are both passed
223to 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';
455d031c 226 %hash = Dlog_trace { "Very handy: $_" } ( foo => 'bar' );
d672a9bf 227
228=item logS_<level> and DlogS_<level>
230Works just like log_ and Dlog_ except returns only the first argument as a scalar value.
232 my $beverage = log_info { "Customer ordered $_[0]" } 'Coffee';
234=item Elog_<level>
236Log an event and then generate an exception by calling die() with the log message.
238 Elog_error { "Could not open file: $!" };
240=item Flog_<level>
242Log the event, generate a warning with the log message, then call exit(). The exit
243value will default to 1 or can be specified as an argument.
245 Flog_fatal { 'Could not lock resource' } 3;
249=head1 LEVEL NAMES
251Object::Remote uses an ordered list of log level names with the minimum level
252first and the maximum level last. The list of level names can be accessed via
253the arg_levels method which is exportable to the consumer of this class. The log
254level names are:
256=over 4
258=item trace
260As much information about operation as possible including multiple line dumps of
261large content. Tripple verbose operation (-v -v -v).
263=item debug
265Messages about operations that could hang as well as internal state changes,
266results from method invocations, and information useful when looking for faults.
267Double verbose operation (-v -v).
269=item verbose
271Additional optional messages to the user that can be enabled at their will. Single
272verbose operation (-v).
274=item info
276Messages from normal operation that are intended to be displayed to the end
277user if quiet operation is not indicated and more verbose operation is not
278in effect.
280=item warn
282Something wasn't supposed to happen but did. Operation was not impacted but
283otherwise the event is noteworthy. Single quiet operation (-q).
285=item error
287Something went wrong. Operation of the system may continue but some operation
288has most definitely failed. Double quiet operation (-q -q).
290=item fatal
292Something went wrong and recovery is not possible. The system should stop operating
293as soon as possible. Tripple quiet operation (-q -q -q).