1Object::Remote::LoggingU(s3e)r Contributed Perl DocumentaOtbijoenct::Remote::Logging(3)
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6 Object::Remote::Logging - Logging subsystem for Object::Remote
7
9 use Object::Remote::Logging qw( :log :dlog arg_levels router );
10 $levels = [qw( trace debug verbose info warn error fatal )];
12 $levels = arg_levels(); #same result
13 $ENV{OBJECT_REMOTE_LOG_LEVEL} = 'trace'; #or other level name
15 $ENV{OBJECT_REMOTE_LOG_FORMAT} = '%l %t: %p::%m %s'; #and more
16 #Output logs from two specific logging pacakges
17 $ENV{OBJECT_REMOTE_LOG_SELECTIONS} = 'Object::Remote::Logging Some::Other::Package';
18 #Output all log messages except those generated by Object::Remote
19 $ENV{OBJECT_REMOTE_LOG_SELECTIONS} = '* -Object::Remote::Logging';
20 $ENV{OBJECT_REMOTE_LOG_FORWARDING} = 1; #default 0
21 log_info { 'Trace log event' };
23 Dlog_verbose { "Debug event with Data::Dumper::Concise: $_" } { foo => 'bar' };
24
26 This is the logging framework for Object::Remote implemented as an
27 extension of Log::Contextual with a slightly incompatible API. This
28 system allows developers using Object::Remote and end users of that
29 software to control Object::Remote logging so operation can be tracked
30 if needed. This is also the API used to generate log messages inside
31 the Object::Remote source code.
32 The rest of the logging system comes from
34 Object::Remote::Logging::Logger which implements log rendering and
35 output and Object::Remote::Logging::Router which delivers log events to
36 the loggers.
37
39 Object::Remote logging output is not enabled by default. If you need to
40 immediately start debugging set the OBJECT_REMOTE_LOG_LEVEL environment
41 variable to either 'trace' or 'debug'. This will enable logging to
42 STDERR on the local and all remote Perl interpreters. By default STDERR
43 for all remote interpreters is passed through unmodified so this is
44 sufficient to receive logs generated anywhere Object::Remote is
45 running.
46 Every time the local interpreter creates a new
48 Object::Remote::Connection the connection is given an id that is unique
49 to that connection on the local interpreter. The connection id and
50 other metadata is available in the log output via a log format string
51 that can be set via the OBJECT_REMOTE_LOG_FORMAT environment variable.
52 The format string and available metadata is documented in
53 Object::Remote::Logging::Logger. Setting this environment variable on
54 the local interpreter will cause it to be propagated to the remote
55 interpreter so all logs will be formated the same way.
56 This system is designed so any module can create their own logging
58 packages using it. With out any additional configuration the consumers
59 of this logging system will automatically be enabled via
60 OBJECT_REMOTE_LOG_LEVEL and formated with OBJECT_REMOTE_LOG_FORMAT but
61 those additional log messages are not sent to STDERR. By setting the
62 OBJECT_REMOTE_LOG_SELECTIONS environment variable to a list of logging
63 package names seperated by spaces then logs generated using those
64 packages will be sent to STDERR. If the asterisk character (*) is used
65 in the place of a package name then all package names will be selected
66 by default instead of ignored. An individual package name can be turned
67 off by prefixing the name with a hypen character (-). This is also a
68 configuration item that is forwarded to the remote interpreters so all
69 logging is consistent.
70 Regardless of OBJECT_REMOTE_LOG_LEVEL the logging system is still
72 active and loggers can access the stream of log messages to format and
73 output them. Internally OBJECT_REMOTE_LOG_LEVEL causes an
74 Object::Remote::Logging::Logger to be built and connected to the
75 Object::Remote::Logging::Router instance. It is also possible to
76 manually build a logger instance and connect it to the router. See the
77 Object::Remote::Logging documentation for more information.
78 The logging system also supports a method of forwarding log messages
80 from remote interpreters to the local interpreter. Forwarded log
81 messages are generated in the remote interpreter and the logger for the
82 message is invoked in the local interpreter. Packages using or
83 extending Object::Remote::Logging will have log messages forwarded
84 automatically. Loggers receive forwarded log messages exactly the same
85 way as non-forwarded messages except a forwarded message includes extra
86 metadata about the remote connection. Log forwarding is disabled by
87 default because it comes with a performance hit; to enable it set the
88 OBJECT_REMOTE_LOG_FORWARDING environment variable to 1.
89
91 arg_levels
92 Returns an array reference that contains the ordered list of level
93 names with the lowest log level first and the highest log level
94 last.
95 router
97 Returns the instance of Object::Remote::Logging::Router that is in
98 use. The router instance is used in combination with
99 Object::Remote::Logging::Logger objects to select then render and
100 output log messages.
101 log_<level> and Dlog_<level>
103 These methods come direct from Log::Contextual; see that
104 documentation for a complete reference. For each of the log level
105 names there are subroutines with the log_ and Dlog_ prefix that
106 will generate the log message. The first argument is a code block
107 that returns the log message contents and the optional further
108 arguments are both passed to the block as the argument list and
109 returned from the log method as a list.
110 log_trace { "A fine log message $_[0] " } 'if I do say so myself';
112 %hash = Dlog_trace { "Very handy: $_" } ( foo => 'bar' );
113 logS_<level> and DlogS_<level>
115 Works just like log_ and Dlog_ except returns only the first
116 argument as a scalar value.
117 my $beverage = logS_info { "Customer ordered $_[0]" } 'Coffee';
119
121 Object::Remote uses an ordered list of log level names with the lowest
122 level first and the highest level last. The list of level names can be
123 accessed via the arg_levels method which is exportable to the consumer
124 of this class. The log level names are:
125 trace
127 As much information about operation as possible including multiple
128 line dumps of large content. Tripple verbose operation (-v -v -v).
129 debug
131 Messages about operations that could hang as well as internal state
132 changes, results from method invocations, and information useful
133 when looking for faults. Double verbose operation (-v -v).
134 verbose
136 Additional optional messages to the user that can be enabled at
137 their will. Single verbose operation (-v).
138 info
140 Messages from normal operation that are intended to be displayed to
141 the end user if quiet operation is not indicated and more verbose
142 operation is not in effect.
143 warn
145 Something wasn't supposed to happen but did. Operation was not
146 impacted but otherwise the event is noteworthy. Single quiet
147 operation (-q).
148 error
150 Something went wrong. Operation of the system may continue but some
151 operation has most definitely failed. Double quiet operation (-q
152 -q).
153 fatal
155 Something went wrong and recovery is not possible. The system
156 should stop operating as soon as possible. Tripple quiet operation
157 (-q -q -q).
158perl v5.30.0 2019-07-26 Object::Remote::Logging(3)