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