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1 | package Object::Remote::Logging; |
2 | |
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3 | use Moo; |
4 | use Scalar::Util qw(blessed); |
5 | use Object::Remote::Logging::Logger; |
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6 | use Exporter::Declare; |
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7 | use Carp qw(carp croak); |
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8 | |
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9 | extends 'Log::Contextual'; |
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10 | |
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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 => ('____'); |
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16 | |
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17 | sub router { |
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18 | our $Router_Instance ||= do { |
19 | require Object::Remote::Logging::Router; |
20 | Object::Remote::Logging::Router->new; |
21 | } |
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22 | } |
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23 | |
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24 | #log level descriptions |
25 | #info - standard log level - normal program output for the end user |
26 | #warn - output for program that is executing quietly |
27 | #error - output for program that is running more quietly |
28 | #fatal - it is not possible to continue execution; this level is as quiet as is possible |
29 | #verbose - output for program executing verbosely (-v) |
30 | #debug - output for program running more verbosely (-v -v) |
31 | #trace - output for program running extremely verbosely (-v -v -v) |
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32 | sub arg_levels { |
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33 | #the order of the log levels is significant with the |
34 | #most verbose level being first in the list and the |
35 | #most quiet as the last item |
36 | return [qw( trace debug verbose info warn error fatal )]; |
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37 | } |
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38 | |
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39 | sub before_import { |
40 | my ($class, $importer, $spec) = @_; |
41 | my $router = $class->router; |
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42 | our $DID_INIT; |
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43 | |
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44 | unless($DID_INIT) { |
45 | $DID_INIT = 1; |
46 | init_logging(); |
47 | } |
48 | |
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49 | $class->SUPER::before_import($importer, $spec); |
50 | |
51 | my @levels = @{$class->arg_levels($spec->config->{levels})}; |
52 | for my $level (@levels) { |
53 | if ($spec->config->{elog}) { |
54 | $spec->add_export("&Elog_$level", sub (&) { |
55 | my ($code, @args) = @_; |
56 | $router->handle_log_request({ |
57 | controller => $class, |
58 | package => scalar(caller), |
59 | caller_level => 1, |
60 | level => $level, |
61 | }, $code); |
62 | #TODO this should get fed into a logger so it can be formatted |
63 | croak $code->(); |
64 | }); |
65 | } |
66 | if ($spec->config->{flog}) { |
67 | #TODO that prototype isn't right |
68 | $spec->add_export("&Flog_$level", sub (&@) { |
69 | my ($code, $exit_value) = @_; |
70 | $exit_value = 1 unless defined $exit_value; |
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71 | #don't let it going wrong stop us from calling exit() |
72 | eval { $router->handle_log_request({ |
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73 | controller => $class, |
74 | package => scalar(caller), |
75 | caller_level => 1, |
76 | level => $level, |
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77 | }, $code) }; |
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78 | warn "could not deliver log event during Flog_$level: $@" if $@; |
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79 | eval { carp $code->() }; |
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80 | warn "could not emit warning during Flog_$level: $@" if $@; |
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81 | exit($exit_value); |
82 | }); |
83 | } |
84 | } |
85 | } |
86 | |
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87 | sub _parse_selections { |
88 | my ($selections_string) = @_; |
89 | my %log_ok; |
90 | |
91 | #example string: |
92 | #" * -Object::Remote::Logging Foo::Bar::Baz " |
93 | foreach(split(/\s+/, $selections_string)) { |
94 | next if $_ eq ''; |
95 | if ($_ eq '*') { |
96 | $log_ok{$_} = 1; |
97 | } elsif (s/^-//) { |
98 | $log_ok{$_} = 0; |
99 | } else { |
100 | $log_ok{$_} = 1; |
101 | } |
102 | } |
103 | |
104 | return %log_ok; |
105 | } |
106 | |
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107 | #this is invoked on all nodes |
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108 | sub init_logging { |
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109 | my $level = $ENV{OBJECT_REMOTE_LOG_LEVEL}; |
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110 | my $format = $ENV{OBJECT_REMOTE_LOG_FORMAT}; |
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111 | my $selections = $ENV{OBJECT_REMOTE_LOG_SELECTIONS}; |
112 | my %controller_should_log; |
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113 | |
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114 | return unless defined $level; |
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115 | $format = "[%l %r] %s" unless defined $format; |
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116 | $selections = __PACKAGE__ unless defined $selections; |
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117 | %controller_should_log = _parse_selections($selections); |
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118 | |
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119 | my $logger = Object::Remote::Logging::Logger->new( |
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120 | min_level => lc($level), format => $format, |
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121 | level_names => Object::Remote::Logging::arg_levels(), |
122 | ); |
123 | |
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124 | router()->connect(sub { |
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125 | my $controller = $_[1]->{controller}; |
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126 | my $will_log = $controller_should_log{$controller}; |
127 | |
128 | $will_log = $controller_should_log{'*'} unless defined $will_log; |
129 | |
130 | return unless $will_log; |
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131 | #skip things from remote hosts because they log to STDERR |
132 | #when OBJECT_REMOTE_LOG_LEVEL is in effect |
133 | return if $_[1]->{remote}->{connection_id}; |
134 | $logger |
135 | }); |
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136 | } |
137 | |
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138 | #this is invoked by the controlling node |
139 | #on the remote nodes |
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140 | sub init_logging_forwarding { |
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141 | my ($self, %controller_info) = @_; |
142 | |
143 | router()->_remote_metadata({ connection_id => $controller_info{connection_id} }); |
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144 | #TODO having an instance of an object in the remote interpreter causes it to hang |
145 | #on exit intermitently or leave a zombie laying around frequently - not a bug limited |
146 | #to log forwarding |
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147 | router()->_forward_destination($controller_info{router}) if $ENV{OBJECT_REMOTE_LOG_FORWARDING}; |
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148 | } |
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149 | |
150 | 1; |
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151 | |
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152 | __END__ |
153 | |
154 | =head1 NAME |
155 | |
156 | Object::Remote::Logging - Logging subsystem for Object::Remote |
157 | |
158 | =head1 SYNOPSIS |
159 | |
160 | use Object::Remote::Logging qw( :log :dlog :elog :flog arg_levels router ); |
161 | |
162 | @levels = qw( trace debug verbose info warn error fatal ); |
163 | @levels = arg_levels(); #same result |
164 | |
165 | $ENV{OBJECT_REMOTE_LOG_LEVEL} = 'trace'; #or other level name |
166 | $ENV{OBJECT_REMOTE_LOG_FORMAT} = '%l %t: %p::%m %s'; #and more |
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167 | $ENV{OBJECT_REMOTE_LOG_SELECTIONS} = 'Object::Remote::Logging Some::Other::Subclass'; |
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168 | $ENV{OBJECT_REMOTE_LOG_SELECTIONS} = '* -Object::Remote::Logging'; |
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169 | $ENV{OBJECT_REMOTE_LOG_FORWARDING} = 0 || 1; #default 0 |
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170 | |
171 | log_info { 'Trace log event' }; |
172 | Dlog_verbose { "Debug event with Data::Dumper::Concise: $_" } { foo => 'bar' }; |
173 | Elog_error { 'Error event that calls die() with this string' }; |
174 | Flog_fatal { 'Fatal event calls warn() then exit()' } 1; |
175 | |
176 | =head1 DESCRIPTION |
177 | |
178 | This is the logging framework for Object::Remote implemented as a subclass of |
179 | L<Log::Contextual> with a slightly incompatible API. This system allows |
180 | developers using Object::Remote and end users of that software to control |
181 | Object::Remote logging so operation can be tracked if needed. This is also |
182 | the API used to generate log messages inside the Object::Remote source code. |
183 | |
184 | The rest of the logging system comes from L<Object::Remote::Logging::Logger> |
185 | which implements log rendering and output and L<Object::Remote::Logging::Router> |
186 | which delivers log events to the loggers. |
187 | |
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188 | =head1 USAGE |
189 | |
190 | Object::Remote logging is not enabled by default. If you need to immediately start |
191 | debugging set the OBJECT_REMOTE_LOG_LEVEL environment variable to either 'trace' |
192 | or 'debug'. This will enable logging to STDERR on the local and all remote Perl |
193 | interpreters. By default STDERR for all remote interpreters is passed through |
194 | unmodified so this is sufficient to receive logs generated anywhere Object::Remote |
195 | is running. |
196 | |
197 | Every time the local interpreter creates a new Object::Remote::Connection the connection |
198 | is given an id that is unique to that connection on the local interpreter. The connection |
199 | id and other metadata is available in the log output via a log format string that can |
200 | be set via the OBJECT_REMOTE_LOG_FORMAT environment variable. The format string and |
201 | available metadata is documented in L<Object::Remote::Logging::Logger>. Setting this |
202 | environment variable on the local interpreter will cause it to be propagated to the |
203 | remote interpreter so all logs will be formated the same way. |
204 | |
205 | This class is designed so any module can create their own logging sub-class using it. |
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206 | With out any additional configuration the consumers of this logging class will |
207 | automatically be enabled via OBJECT_REMOTE_LOG_LEVEL and formated with |
208 | OBJECT_REMOTE_LOG_FORMAT but those additional log messages are not sent to STDERR. |
209 | By setting the OBJECT_REMOTE_LOG_SELECTIONS environment variable to a list of |
210 | class names seperated by spaces then logs generated by packages that use those classes |
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211 | will be sent to STDERR. If the asterisk character (*) is used in the place of a class |
212 | name then all class names will be selected by default instead of ignored. An individual |
213 | class name can be turned off by prefixing the name with a hypen character (-). This is |
214 | also a configuration item that is forwarded to the remote interpreters so all logging |
215 | is consistent. |
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216 | |
217 | Regardless of OBJECT_REMOTE_LOG_LEVEL the logging system is still active and loggers |
218 | can access the stream of log messages to format and output them. Internally |
219 | OBJECT_REMOTE_LOG_LEVEL causes an L<Object::Remote::Logging::Logger> to be built |
220 | and connected to the L<Object::Remote::Logging::Router> instance. It is also possible |
221 | to manually build a logger instance and connect it to the router. See the documentation |
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222 | for the logger and router classes. |
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223 | |
224 | The logging system also supports a method of forwarding log messages from remote |
225 | interpreters to the local interpreter. Forwarded log messages are generated in the |
226 | remote interpreter and the logger for the message is invoked in the local interpreter. |
227 | Sub-classes of Object::Remote::Logging will have log messages forwarded automatically. |
228 | Loggers receive forwarded log messages exactly the same way as non-forwarded messages |
229 | except a forwarded message includes extra metadata about the remote interpreter. Log |
230 | forwarding is not currently enabled by default; to enable it set the |
231 | OBJECT_REMOTE_LOG_FORWARDING environment variable to 1. See L<Object::Remote::Logging::Router>. |
232 | |
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233 | =head1 EXPORTABLE SUBROUTINES |
234 | |
235 | =over 4 |
236 | |
237 | =item arg_levels |
238 | |
239 | Returns an array reference that contains the ordered list of level names |
240 | with the lowest log level first and the highest log level last. |
241 | |
242 | =item router |
243 | |
244 | Returns the instance of L<Object::Remote::Logging::Router> that is in use. The router |
245 | instance is used in combination with L<Object::Remote::Logging::Logger> objects to |
246 | select then render and output log messages. |
247 | |
248 | =item log_<level> and Dlog_<level> |
249 | |
250 | These methods come direct from L<Log::Contextual>; see that documentation for a |
251 | complete reference. For each of the log level names there are subroutines with the log_ |
252 | and Dlog_ prefix that will generate the log message. The first argument is a code block |
253 | that returns the log message contents and the optional further arguments are both passed |
254 | to the block as the argument list and returned from the log method as a list. |
255 | |
256 | log_trace { "A fine log message $_[0] " } 'if I do say so myself'; |
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257 | %hash = Dlog_trace { "Very handy: $_" } ( foo => 'bar' ); |
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258 | |
259 | =item logS_<level> and DlogS_<level> |
260 | |
261 | Works just like log_ and Dlog_ except returns only the first argument as a scalar value. |
262 | |
263 | my $beverage = log_info { "Customer ordered $_[0]" } 'Coffee'; |
264 | |
265 | =item Elog_<level> |
266 | |
267 | Log an event and then generate an exception by calling die() with the log message. |
268 | |
269 | Elog_error { "Could not open file: $!" }; |
270 | |
271 | =item Flog_<level> |
272 | |
273 | Log the event, generate a warning with the log message, then call exit(). The exit |
274 | value will default to 1 or can be specified as an argument. |
275 | |
276 | Flog_fatal { 'Could not lock resource' } 3; |
277 | |
278 | =back |
279 | |
280 | =head1 LEVEL NAMES |
281 | |
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282 | Object::Remote uses an ordered list of log level names with the lowest level |
283 | first and the highest level last. The list of level names can be accessed via |
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284 | the arg_levels method which is exportable to the consumer of this class. The log |
285 | level names are: |
286 | |
287 | =over 4 |
288 | |
289 | =item trace |
290 | |
291 | As much information about operation as possible including multiple line dumps of |
292 | large content. Tripple verbose operation (-v -v -v). |
293 | |
294 | =item debug |
295 | |
296 | Messages about operations that could hang as well as internal state changes, |
297 | results from method invocations, and information useful when looking for faults. |
298 | Double verbose operation (-v -v). |
299 | |
300 | =item verbose |
301 | |
302 | Additional optional messages to the user that can be enabled at their will. Single |
303 | verbose operation (-v). |
304 | |
305 | =item info |
306 | |
307 | Messages from normal operation that are intended to be displayed to the end |
308 | user if quiet operation is not indicated and more verbose operation is not |
309 | in effect. |
310 | |
311 | =item warn |
312 | |
313 | Something wasn't supposed to happen but did. Operation was not impacted but |
314 | otherwise the event is noteworthy. Single quiet operation (-q). |
315 | |
316 | =item error |
317 | |
318 | Something went wrong. Operation of the system may continue but some operation |
319 | has most definitely failed. Double quiet operation (-q -q). |
320 | |
321 | =item fatal |
322 | |
323 | Something went wrong and recovery is not possible. The system should stop operating |
324 | as soon as possible. Tripple quiet operation (-q -q -q). |
325 | |
326 | =back |