X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?p=scpubgit%2FObject-Remote.git;a=blobdiff_plain;f=lib%2FObject%2FRemote%2FLogging.pm;h=7eee65f12e4f3eb228bf3b699dafb4167ccaba24;hp=f2fec49e0e268929a841d262407f2b5e03005ab3;hb=a577b9530c7c091e6800bca9dca4fd03c37ce039;hpb=6536ccd3af048ed71845cc5ea453855f45e66971 diff --git a/lib/Object/Remote/Logging.pm b/lib/Object/Remote/Logging.pm index f2fec49..7eee65f 100644 --- a/lib/Object/Remote/Logging.pm +++ b/lib/Object/Remote/Logging.pm @@ -1,220 +1,292 @@ package Object::Remote::Logging; -use strictures 1; - -use Object::Remote::LogRouter; -use Object::Remote::LogDestination; -use Log::Contextual::SimpleLogger; -use Carp qw(cluck); - -use base qw(Log::Contextual); - -sub arg_router { - return $_[1] if defined $_[1]; - our $Router_Instance; - - return $Router_Instance if defined $Router_Instance; - - $Router_Instance = Object::Remote::LogRouter->new( - description => $_[0], - ); +use Moo; +use Scalar::Util qw(blessed); +use Object::Remote::Logging::Logger; +use Exporter::Declare; +use Carp qw(carp croak); + +extends 'Log::Contextual'; + +exports(qw( ____ router arg_levels )); + +sub router { + our $Router_Instance ||= do { + require Object::Remote::Logging::Router; + Object::Remote::Logging::Router->new; + } } -sub init_logging { - my ($class) = @_; - our $Did_Init; - - return if $Did_Init; - $Did_Init = 1; +#log level descriptions +#info - standard log level - normal program output for the end user +#warn - output for program that is executing quietly +#error - output for program that is running more quietly +#fatal - it is not possible to continue execution; this level is as quiet as is possible +#verbose - output for program executing verbosely (-v) +#debug - output for program running more verbosely (-v -v) +#trace - output for program running extremely verbosely (-v -v -v) +sub arg_levels { + #the order of the log levels is significant with the + #most verbose level being first in the list and the + #most quiet as the last item + return [qw( trace debug verbose info warn error fatal )]; +} + +sub before_import { + my ($class, $importer, $spec) = @_; + my $router = $class->router; + our $DID_INIT; + + unless($DID_INIT) { + $DID_INIT = 1; + init_logging(); + } + + $class->SUPER::before_import($importer, $spec); +} + +sub _parse_selections { + my ($selections_string) = @_; + my %log_ok; - if ($ENV{OBJECT_REMOTE_LOG_LEVEL}) { - $class->init_logging_stderr($ENV{OBJECT_REMOTE_LOG_LEVEL}); + #example string: + #" * -Object::Remote::Logging Foo::Bar::Baz " + foreach(split(/\s+/, $selections_string)) { + next if $_ eq ''; + if ($_ eq '*') { + $log_ok{$_} = 1; + } elsif (s/^-//) { + $log_ok{$_} = 0; + } else { + $log_ok{$_} = 1; + } } + + return %log_ok; } -sub init_logging_stderr { - my ($class, $level) = @_; - our $Log_Level = $level; - chomp(my $hostname = `hostname`); +#this is invoked on all nodes +sub init_logging { + my $level = $ENV{OBJECT_REMOTE_LOG_LEVEL}; + my $format = $ENV{OBJECT_REMOTE_LOG_FORMAT}; + my $selections = $ENV{OBJECT_REMOTE_LOG_SELECTIONS}; + my $test_logging = $ENV{OBJECT_REMOTE_TEST_LOGGER}; + my %controller_should_log; - our $Log_Output = Object::Remote::LogDestination->new( - logger => Log::Contextual::SimpleLogger->new({ - levels_upto => $Log_Level, - coderef => sub { - my @t = localtime(); - my $time = sprintf("%0.2i:%0.2i:%0.2i", $t[2], $t[1], $t[0]); - print STDERR "[$hostname $$] $time ", @_ - }, - }) - ); + unless (defined $ENV{OBJECT_REMOTE_LOG_FORWARDING} && $ENV{OBJECT_REMOTE_LOG_FORWARDING} ne '') { + $ENV{OBJECT_REMOTE_LOG_FORWARDING} = 1; + } - $Log_Output->connect($class->arg_router); + if ($test_logging) { + require Object::Remote::Logging::TestLogger; + router->connect(Object::Remote::Logging::TestLogger->new( + min_level => 'trace', max_level => 'error', + level_names => Object::Remote::Logging->arg_levels(), + )); + } + + { + no warnings 'once'; + if (defined $Object::Remote::FatNode::REMOTE_NODE) { + #the connection id for the remote node comes in later + #as the controlling node inits remote logging + router()->_remote_metadata({ connection_id => undef }); + } + } + + return unless defined $level && $level ne ''; + + $format = "[%l %r] %s" unless defined $format; + $selections = __PACKAGE__ unless defined $selections; + %controller_should_log = _parse_selections($selections); + + my $logger = Object::Remote::Logging::Logger->new( + min_level => lc($level), format => $format, + level_names => Object::Remote::Logging::arg_levels(), + ); + + router()->connect(sub { + my $controller = $_[1]->{controller}; + my $will_log = $controller_should_log{$controller}; + + $will_log = $controller_should_log{'*'} unless defined $will_log; + + return unless $will_log; + #skip things from remote hosts because they log to STDERR + #when OBJECT_REMOTE_LOG_LEVEL is in effect + return if $_[1]->{remote}->{object_remote}; + $logger + }); } -sub init_logging_forwarding { -# my ($class, $remote_parent) = @_; -# chomp(my $host = `hostname`); -# $class->arg_router->description("$$ $host"); -# $class->arg_router->parent_router($remote_parent); -# $remote_parent->add_child_router($class->arg_router); +#this is invoked by the controlling node +#on the remote nodes +sub init_remote_logging { + my ($self, %controller_info) = @_; + + router()->_remote_metadata(\%controller_info); + router()->_forward_destination($controller_info{router}) if $ENV{OBJECT_REMOTE_LOG_FORWARDING}; } 1; __END__ -Hierarchical routed logging concept +=head1 NAME - Why? - - Object::Remote and systems built on it would benefit from a standard model - for logging that enables simple and transparent log generation and consumption - that can cross the Perl interpreter instance boundaries. More - generally CPAN would benefit from a common logging framework that allows all - log message generators to play nicely with all log message consumers with out - making the generators or consumers jump through hoops to do what they want to do. - If these two solutions are the same then all modules built using the - logging framework will transparently operate properly when run under Object::Remote. +Object::Remote::Logging - Logging subsystem for Object::Remote + +=head1 SYNOPSIS + + use Object::Remote::Logging qw( :log :dlog arg_levels router ); - Such a solution needs to be flexible and have a low performance impact when it is not - actively logging. The hiearchy of log message routers is the way to achieve all of these - goals. The abstracted message router interface introduced to Log::Contextual allows - the hierarchical routing system to be built and tested inside Object::Remote with possible - larger scale deployment in the future. + @levels = qw( trace debug verbose info warn error fatal ); + @levels = arg_levels(); #same result - Hierarchy of log routers + $ENV{OBJECT_REMOTE_LOG_LEVEL} = 'trace'; #or other level name + $ENV{OBJECT_REMOTE_LOG_FORMAT} = '%l %t: %p::%m %s'; #and more + $ENV{OBJECT_REMOTE_LOG_SELECTIONS} = 'Object::Remote::Logging Some::Other::Subclass'; + $ENV{OBJECT_REMOTE_LOG_SELECTIONS} = '* -Object::Remote::Logging'; + $ENV{OBJECT_REMOTE_LOG_FORWARDING} = 0; #default 1 - * Each Perl module ideally would use at least a router dedicated - to that module and may have child routers if the module is complex. - - * Log messages inserted at low levels in the hierarchy - are available at routers at higher levels in the hierarchy. - - * Each running Perl instance has a root router which receives - all log messages generated in the Perl instance. - - * The routing hierarchy is available for introspection and connections - from child routers to parent routers have human readable descriptions - - * The entire routing system is dynamic - * Add and remove routers while the system is in operation - * Add and remove subscriptions into routers while the system is in operation - - * Auto-solves Object::Remote logging by setting the parent router of the - root router in the remote instance to a router in the local instance. The - log messages will flow into the local router via a proxy object. - - * There needs to be two modes of operation for routed logging - * forwarding across Perl instances using Object::Remote proxies - for ease of use during normal operation - - * STDERR output by default because not all logs can be forwarded - such as log messages for parts of Object::Remote that relate to - Object::Remote delivering the log. - + log_info { 'Trace log event' }; + Dlog_verbose { "Debug event with Data::Dumper::Concise: $_" } { foo => 'bar' }; +=head1 DESCRIPTION - Example hiearchy - - * Root [1] - * System::Introspector - * Object::Remote [2] - * local [3] - * remote [4] - * connection #1 [5] - * Root - * System::Introspector - * Object::Remote - * local - * connection #2 - * Root - * System::Introspector - * Object::Remote - * local - - [1] This router has all logs generated anywhere - even on remote hosts - [2] Everything related to Object::Remote including - log messages from remote nodes for things other - than Object::Remote - [3] Log messages generated by Object::Remote on the local - node only - [4] All log messages from all remote nodes - [5] This is the connection from a remote instance to the - local instance using a proxy object - the name contains - the Object::Remote::Connection id for the remote node - - As a demonstration of the flexibility of the this system consider a CPAN testers GUI - tool. This hypothetical tool would allow a tester to select a module by name and perform - the automated tests for that package and all dependent packages. Inside the tool is a pane for - the output of the process (STDOUT and STDERR), a pane for log messages, and a pane displaying - the modules that are participating in routed logging. The tester could then click on individual - packages and enable logging for that package dynamically. If neccassary more than one package - could be monitored if neccassary. If the GUI is wrapping a program that runs for long periods of - time or if the application is a daemon then being able to dynamically add and remove logging - becomes very useful. - - Log message selection and output - - * Assumptions - * Modules and packages know how they want to format log messages. - * Consumers of log messages want to know - * Which Perl module/package generated that message. - * When running with Object::Remote if the log message is from - a remote connection and if so which connection. - * Consumers of a log message know how they want to output them. The logger - should not be enforcing a specific type of log output. - * Most log messages most of the time will be completely ignored and unused. - * Router subscriptions - * A consumer of log messages will subscribe to a router at any arbitrary point - in the router hierarchy even across machines if Object::Remote is involved - * The subscription is used to access a stream of log data and is not used to select - which packages/modules should be logged - * For instance the Object::Remote log router has log messages flowing through - it that include logs generated on remote nodes even if those logs were generated - by a module other than Object::Remote - - * Selection - * The module has defined what the log message format is - * The subscription has defined the scope of messages that will be - available for selection, ie: all log messages everywhere, - all logs generated on Object::Remote nodes, etc - * Selection defines what log messages are going to be delivered - to a logger object instance - * Selectors act as a gate between a subscription and the logger object - * Selectors are closures that perform introspection on the log - message and metadata; if the selector returns true the logger - will be invoked to log this message - * The logger still has a log level assigned to it and still will have - the is_$level method invoked to only log at that specific level - - * Destinations - * A log destination is an instance of a logger object and the associated - subscriptions. - * Consuming logging data from this system is a matter of - * Constructing an instance of a logging destination object which has - the following attributes: - * logger - the logger object - * selectors - a list of closures; the first one that returns true - causes the logger to be checked for this log_level and - invoked if needed - * Register selectors with the destination by invoking a method and specifying - sub refs as an argument - - Technical considerations - * The routing hierarchy has cycles where parent routers hold a reference to the child - and the child holds a reference to the parent. The cycles are not a problem if weak - references are used however proxy objects don't seem to currently work with weak - references. - * Once a logger hits a proxy object the caller information is totally blown; this - crossing isn't transparent yet - * If Object::Remote is logging its actions and those logs are being forwarded then - logs can be generated from the forwarding itself creating an infinite loop. Only - a portion of Object::Remote can be forwarded. - - - +This is the logging framework for Object::Remote implemented as a subclass of +L with a slightly incompatible API. This system allows +developers using Object::Remote and end users of that software to control +Object::Remote logging so operation can be tracked if needed. This is also +the API used to generate log messages inside the Object::Remote source code. + +The rest of the logging system comes from L +which implements log rendering and output and L +which delivers log events to the loggers. + +=head1 USAGE + +Object::Remote logging is not enabled by default. If you need to immediately start +debugging set the OBJECT_REMOTE_LOG_LEVEL environment variable to either 'trace' +or 'debug'. This will enable logging to STDERR on the local and all remote Perl +interpreters. By default STDERR for all remote interpreters is passed through +unmodified so this is sufficient to receive logs generated anywhere Object::Remote +is running. + +Every time the local interpreter creates a new Object::Remote::Connection the connection +is given an id that is unique to that connection on the local interpreter. The connection +id and other metadata is available in the log output via a log format string that can +be set via the OBJECT_REMOTE_LOG_FORMAT environment variable. The format string and +available metadata is documented in L. Setting this +environment variable on the local interpreter will cause it to be propagated to the +remote interpreter so all logs will be formated the same way. + +This class is designed so any module can create their own logging sub-class using it. +With out any additional configuration the consumers of this logging class will +automatically be enabled via OBJECT_REMOTE_LOG_LEVEL and formated with +OBJECT_REMOTE_LOG_FORMAT but those additional log messages are not sent to STDERR. +By setting the OBJECT_REMOTE_LOG_SELECTIONS environment variable to a list of +class names seperated by spaces then logs generated by packages that use those classes +will be sent to STDERR. If the asterisk character (*) is used in the place of a class +name then all class names will be selected by default instead of ignored. An individual +class name can be turned off by prefixing the name with a hypen character (-). This is +also a configuration item that is forwarded to the remote interpreters so all logging +is consistent. + +Regardless of OBJECT_REMOTE_LOG_LEVEL the logging system is still active and loggers +can access the stream of log messages to format and output them. Internally +OBJECT_REMOTE_LOG_LEVEL causes an L to be built +and connected to the L instance. It is also possible +to manually build a logger instance and connect it to the router. See the documentation +for the logger and router classes. + +The logging system also supports a method of forwarding log messages from remote +interpreters to the local interpreter. Forwarded log messages are generated in the +remote interpreter and the logger for the message is invoked in the local interpreter. +Sub-classes of Object::Remote::Logging will have log messages forwarded automatically. +Loggers receive forwarded log messages exactly the same way as non-forwarded messages +except a forwarded message includes extra metadata about the remote interpreter. Log +forwarding is enabled by default but comes with a performance hit; to disable it set the +OBJECT_REMOTE_LOG_FORWARDING environment variable to 0. See L. + +=head1 EXPORTABLE SUBROUTINES + +=over 4 + +=item arg_levels + +Returns an array reference that contains the ordered list of level names +with the lowest log level first and the highest log level last. + +=item router + +Returns the instance of L that is in use. The router +instance is used in combination with L objects to +select then render and output log messages. + +=item log_ and Dlog_ + +These methods come direct from L; see that documentation for a +complete reference. For each of the log level names there are subroutines with the log_ +and Dlog_ prefix that will generate the log message. The first argument is a code block +that returns the log message contents and the optional further arguments are both passed +to the block as the argument list and returned from the log method as a list. + + log_trace { "A fine log message $_[0] " } 'if I do say so myself'; + %hash = Dlog_trace { "Very handy: $_" } ( foo => 'bar' ); + +=item logS_ and DlogS_ + +Works just like log_ and Dlog_ except returns only the first argument as a scalar value. + + my $beverage = logS_info { "Customer ordered $_[0]" } 'Coffee'; + +=back + +=head1 LEVEL NAMES + +Object::Remote uses an ordered list of log level names with the lowest level +first and the highest level last. The list of level names can be accessed via +the arg_levels method which is exportable to the consumer of this class. The log +level names are: + +=over 4 + +=item trace + +As much information about operation as possible including multiple line dumps of +large content. Tripple verbose operation (-v -v -v). + +=item debug + +Messages about operations that could hang as well as internal state changes, +results from method invocations, and information useful when looking for faults. +Double verbose operation (-v -v). + +=item verbose + +Additional optional messages to the user that can be enabled at their will. Single +verbose operation (-v). + +=item info + +Messages from normal operation that are intended to be displayed to the end +user if quiet operation is not indicated and more verbose operation is not +in effect. + +=item warn + +Something wasn't supposed to happen but did. Operation was not impacted but +otherwise the event is noteworthy. Single quiet operation (-q). + +=item error +Something went wrong. Operation of the system may continue but some operation +has most definitely failed. Double quiet operation (-q -q). +=item fatal +Something went wrong and recovery is not possible. The system should stop operating +as soon as possible. Tripple quiet operation (-q -q -q). +=back