Exception::Base - Lightweight exceptions
# Use module and create needed exceptions
use Exception::Base
'Exception::Runtime', # create new module
'Exception::System', # load existing module
'Exception::IO', => {
isa => 'Exception::System' }, # create new based on existing
'Exception::FileNotFound' => {
isa => 'Exception::IO', # create new based on previous
message => 'File not found', # override default message
has => [ 'filename' ], # define new rw attribute
string_attributes => [ 'message', 'filename' ],
}; # output message and filename
# eval is used as "try" block
eval {
open my $file, '/etc/passwd'
or Exception::FileNotFound->throw(
message=>'Something wrong',
filename=>'/etc/passwd');
};
# syntax for Perl >= 5.10
use feature 'switch';
if ($@) {
given (my $e = Exception::Base->catch) {
when ($e->isa('Exception::IO')) { warn "IO problem"; }
when ($e->isa('Exception::Eval')) { warn "eval died"; }
when ($e->isa('Exception::Runtime')) { warn "some runtime was caught"; }
when ($e->matches({value=>9})) { warn "something happened"; }
when ($e->matches(qr/^Error/)) { warn "some error based on regex"; }
default { $e->throw; } # rethrow the exception
}
}
# standard syntax for older Perl
if ($@) {
my $e = Exception::Base->catch; # convert $@ into exception
if ($e->isa('Exception::IO')) { warn "IO problem"; }
elsif ($e->isa('Exception::Eval')) { warn "eval died"; }
elsif ($e->isa('Exception::Runtime')) { warn "some runtime was caught"; }
elsif ($e->matches({value=>9})) { warn "something happened"; }
elsif ($e->matches(qr/^Error/)) { warn "some error based on regex"; }
else { $e->throw; } # rethrow the exception
}
# $@ has to be recovered ASAP!
eval { die "this die will be caught" };
my $e = Exception::Base->catch;
eval { die "this die will be ignored" };
if ($e) {
(...)
}
# the exception can be thrown later
my $e = Exception::Base->new;
# (...)
$e->throw;
# ignore our package in stack trace
package My::Package;
use Exception::Base '+ignore_package' => __PACKAGE__;
# define new exception in separate module
package Exception::My;
use Exception::Base (__PACKAGE__) => {
has => ['myattr'],
};
# run Perl with changed verbosity for debugging purposes
$ perl -MException::Base=verbosity,4 script.pl
This class implements a fully OO exception mechanism similar to Exception::Class or Class::Throwable. It provides a simple interface allowing programmers to declare exception classes. These classes can be thrown and caught. Each uncaught exception prints full stack trace if the default verbosity is increased for debugging purposes.
The features of Exception::Base
:
- fast implementation of the exception class
- fully OO without closures and source code filtering
- does not mess with
$SIG{__DIE__}
and$SIG{__WARN__}
- no external run-time modules dependencies, requires core Perl modules only
- the default behavior of exception class can be changed globally or just for the thrown exception
- matching the exception by class, message or other attributes
- matching with string, regex or closure function
- creating automatically the derived exception classes ("use" in perlfunc interface)
- easily expendable, see Exception::System class for example
- prints just an error message or dumps full stack trace
- can propagate (rethrow) an exception
- can ignore some packages for stack trace output
- some defaults (i.e. verbosity) can be different for different exceptions
-
Boolean context
True value. See
to_bool
method.eval { Exception::Base->throw( message=>"Message", value=>123 ) }; if ($@) { # the exception object is always true }
-
Numeric context
Content of attribute pointed by
numeric_attribute
attribute. Seeto_number
method.eval { Exception::Base->throw( message=>"Message", value=>123 ) }; print 0+$@; # 123
-
String context
Content of attribute which is combined from
string_attributes
attributes with additional information, depended onverbosity
setting. Seeto_string
method.eval { Exception::Base->throw( message=>"Message", value=>123 ) }; print "$@"; # "Message at -e line 1.\n"
-
"~~"
Smart matching operator. See
matches
method.eval { Exception::Base->throw( message=>"Message", value=>123 ) }; print "Message" ~~ $@; # 1 print qr/message/i ~~ $@; # 1 print ['Exception::Base'] ~~ $@; # 1 print 123 ~~ $@; # 1 print {message=>"Message", value=>123} ~~ $@; # 1
Warning: The smart operator requires that the exception object is a second argument.
-
ATTRS
Declaration of class attributes as reference to hash.
The attributes are listed as name => {properties}, where properties is a list of attribute properties:
-
is
Can be 'rw' for read-write attributes or 'ro' for read-only attributes. The attribute is read-only and does not have an accessor created if 'is' property is missed.
-
default
Optional property with the default value if the attribute value is not defined.
The read-write attributes can be set with
new
constructor. Read-only attributes and unknown attributes are ignored.The constant have to be defined in derived class if it brings additional attributes.
package Exception::My; use base 'Exception::Base'; # Define new class attributes use constant ATTRS => { %{Exception::Base->ATTRS}, # base's attributes have to be first readonly => { is=>'ro' }, # new ro attribute readwrite => { is=>'rw', default=>'blah' }, # new rw attribute }; package main; use Exception::Base ':all'; eval { Exception::My->throw( readwrite => 2 ); }; if ($@) { my $e = Exception::Base->catch; print $e->readwrite; # = 2 print $e->defaults->{readwrite}; # = "blah" }
-
Class attributes are implemented as values of blessed hash. The attributes are also available as accessors methods.
-
message (rw, default: 'Unknown exception')
Contains the message of the exception. It is the part of the string representing the exception object.
eval { Exception::Base->throw( message=>"Message" ); }; print $@->message if $@;
It can also be an array reference of strings and then the "perlfunc" in sprintf is used to get a message.
Exception::Base->throw( message => ["%s failed", __PACKAGE__] );
-
value (rw, default: 0)
Contains the value which represents numeric value of the exception object in numeric context.
eval { Exception::Base->throw( value=>2 ); }; print "Error 2" if $@ == 2;
-
verbosity (rw, default: 2)
Contains the verbosity level of the exception object. It allows to change the string representing the exception object. There are following levels of verbosity:
-
0
Empty string
-
1
Message
-
2
Message at %s line %d.
The same as the standard output of die() function. It doesn't include "at %s line %d." string if message ends with
"\n"
character. This is the default option. -
3
Class: Message at %s line %d %c_ = %s::%s() called in package %s at %s line %d ...propagated in package %s at %s line %d. ...
The output contains full trace of error stack without first
ignore_level
lines and those packages which are listed inignore_package
andignore_class
settings. -
4
The output contains full trace of error stack. In this case the
ignore_level
,ignore_package
andignore_class
settings are meaning only for first line of exception's message.
If the verbosity is undef, then the default verbosity for exception objects is used.
If the verbosity set with constructor (
new
orthrow
) is lower than 3, the full stack trace won't be collected.If the verbosity is lower than 2, the full system data (time, pid, tid, uid, euid, gid, egid) won't be collected.
This setting can be changed with import interface.
use Exception::Base verbosity => 4;
It can be also changed for Perl interpreter instance, i.e. for debugging purposes.
sh$ perl -MException::Base=verbosity,4 script.pl
-
-
ignore_package (rw)
Contains the name (scalar or regexp) or names (as references array) of packages which are ignored in error stack trace. It is useful if some package throws an exception but this module shouldn't be listed in stack trace.
package My::Package; use Exception::Base; sub my_function { do_something() or throw Exception::Base ignore_package=>__PACKAGE__; throw Exception::Base ignore_package => [ "My", qr/^My::Modules::/ ]; }
This setting can be changed with import interface.
use Exception::Base ignore_package => __PACKAGE__;
-
ignore_class (rw)
Contains the name (scalar) or names (as references array) of packages which are base classes for ignored packages in error stack trace. It means that some packages will be ignored even the derived class was called.
package My::Package; use Exception::Base; Exception::Base->throw( ignore_class => "My::Base" );
This setting can be changed with import interface.
use Exception::Base ignore_class => "My::Base";
-
ignore_level (rw)
Contains the number of level on stack trace to ignore. It is useful if some package throws an exception but this module shouldn't be listed in stack trace. It can be used with or without ignore_package attribute.
# Convert warning into exception. The signal handler ignores itself. use Exception::Base 'Exception::My::Warning'; $SIG{__WARN__} = sub { Exception::My::Warning->throw( message => $_[0], ignore_level => 1 ); };
-
time (ro)
Contains the timestamp of the thrown exception. Collected if the verbosity on throwing exception was greater than 1.
eval { Exception::Base->throw( message=>"Message" ); }; print scalar localtime $@->time;
-
pid (ro)
Contains the PID of the Perl process at time of thrown exception. Collected if the verbosity on throwing exception was greater than 1.
eval { Exception::Base->throw( message=>"Message" ); }; kill 10, $@->pid;
-
tid (ro)
Contains the tid of the thread or undef if threads are not used. Collected if the verbosity on throwing exception was greater than 1.
-
uid (ro)
-
euid (ro)
-
gid (ro)
-
egid (ro)
Contains the real and effective uid and gid of the Perl process at time of thrown exception. Collected if the verbosity on throwing exception was greater than 1.
-
caller_stack (ro)
Contains the error stack as array of array with information about caller functions. The first 8 elements of the array's row are the same as first 8 elements of the output of
caller
function. Further elements are optional and are the arguments of called function. Collected if the verbosity on throwing exception was greater than 1. Contains only the first element of caller stack if the verbosity was lower than 3.If the arguments of called function are references and
[Scalar::Util](http://search.cpan.org/perldoc?Scalar::Util)::weaken
function is available then reference is weakened.eval { Exception::Base->throw( message=>"Message" ); }; ($package, $filename, $line, $subroutine, $hasargs, $wantarray, $evaltext, $is_require, @args) = $@->caller_stack->[0];
-
propagated_stack (ro)
Contains the array of array which is used for generating "...propagated at" message. The elements of the array's row are the same as first 3 elements of the output of
caller
function. -
max_arg_len (rw, default: 64)
Contains the maximal length of argument for functions in backtrace output. Zero means no limit for length.
sub a { Exception::Base->throw( max_arg_len=>5 ) } a("123456789");
-
max_arg_nums (rw, default: 8)
Contains the maximal number of arguments for functions in backtrace output. Zero means no limit for arguments.
sub a { Exception::Base->throw( max_arg_nums=>1 ) } a(1,2,3);
-
max_eval_len (rw, default: 0)
Contains the maximal length of eval strings in backtrace output. Zero means no limit for length.
eval "Exception->throw( max_eval_len=>10 )"; print "$@";
-
defaults
Meta-attribute contains the list of default values.
my $e = Exception::Base->new; print defined $e->{verbosity} ? $e->{verbosity} : $e->{defaults}->{verbosity};
-
default_attribute (default: 'message')
Meta-attribute contains the name of the default attribute. This attribute will be set for one argument throw method. This attribute has meaning for derived classes.
use Exception::Base 'Exception::My' => { has => 'myattr', default_attribute => 'myattr', }; eval { Exception::My->throw("string") }; print $@->myattr; # "string"
-
numeric_attribute (default: 'value')
Meta-attribute contains the name of the attribute which contains numeric value of exception object. This attribute will be used for representing exception in numeric context.
use Exception::Base 'Exception::My' => { has => 'myattr', numeric_attribute => 'myattr', }; eval { Exception::My->throw(myattr=>123) }; print 0 + $@; # 123
-
eval_attribute (default: 'message')
Meta-attribute contains the name of the attribute which is filled if error stack is empty. This attribute will contain value of
$@
variable. This attribute has meaning for derived classes.use Exception::Base 'Exception::My' => { has => 'myattr', eval_attribute => 'myattr' }; eval { die "string" }; print $@->myattr; # "string"
-
string_attributes (default: ['message'])
Meta-attribute contains the array of names of attributes with defined value which are joined to the string returned by
to_string
method. If none of attributes are defined, the string is created from the first default value of attributes listed in the opposite order.use Exception::Base 'Exception::My' => { has => 'myattr', myattr => 'default', string_attributes => ['message', 'myattr'], }; eval { Exception::My->throw( message=>"string", myattr=>"foo" ) }; print $@->myattr; # "string: foo" eval { Exception::My->throw() }; print $@->myattr; # "default"
-
use Exception::Base '_attribute_' =
value;>Changes the default value for attribute. If the attribute name has no special prefix, its default value is replaced with a new value.
use Exception::Base verbosity => 4;
If the attribute name starts with "
+
" or "-
" then the new value is based on previous value:-
If the original value was a reference to array, the new value can be included or removed from original array. Use array reference if you need to add or remove more than one element.
use Exception::Base "+ignore_packages" => [ __PACKAGE__, qr/^Moose::/ ], "-ignore_class" => "My::Good::Class";
-
If the original value was a number, it will be incremented or decremented by the new value.
use Exception::Base "+ignore_level" => 1;
-
If the original value was a string, the new value will be included.
use Exception::Base "+message" => ": The incuded message";
-
-
use Exception::Base '_Exception_', ...;
Loads additional exception class module. If the module is not available, creates the exception class automatically at compile time. The newly created class will be based on
Exception::Base
class.use Exception::Base qw{ Exception::Custom Exception::SomethingWrong }; Exception::Custom->throw;
-
use Exception::Base '_Exception_' =
{ isa => BaseException, version => version, ... };>Loads additional exception class module. If the module's version is lower than given parameter or the module can't be loaded, creates the exception class automatically at compile time. The newly created class will be based on given class and has the given $VERSION variable.
-
isa
The newly created class will be based on given class.
use Exception::Base 'Exception::My', 'Exception::Nested' => { isa => 'Exception::My };
-
version
The class will be created only if the module's version is lower than given parameter and will have the version given in the argument.
use Exception::Base 'Exception::My' => { version => 1.23 };
-
has
The class will contain new rw attribute (if parameter is a string) or new rw attributes (if parameter is a reference to array of strings) or new rw or ro attributes (if parameter is a reference to hash of array of strings with rw and ro as hash key).
use Exception::Base 'Exception::Simple' => { has => 'field' }, 'Exception::More' => { has => [ 'field1', 'field2' ] }, 'Exception::Advanced' => { has => { ro => [ 'field1', 'field2' ], rw => [ 'field3' ] } };
-
message
-
verbosity
-
max_arg_len
-
max_arg_nums
-
max_eval_len
-
other attribute having default property
The class will have the default property for the given attribute.
use Exception::Base 'Exception::WithDefault' => { message => 'Default message' }, 'Exception::Reason' => { has => [ 'reason' ], string_attributes => [ 'message', 'reason' ] };
-
-
new([%args])
Creates the exception object, which can be thrown later. The system data attributes like
time
,pid
,uid
,gid
,euid
,egid
are not filled.If the key of the argument is read-write attribute, this attribute will be filled. Otherwise, the argument will be ignored.
$e = Exception::Base->new( message=>"Houston, we have a problem", unknown_attr => "BIG" ); print $e->{message};
The constructor reads the list of class attributes from ATTRS constant function and stores it in the internal cache for performance reason. The defaults values for the class are also stored in internal cache.
-
CLASS
->throw([%args]])Creates the exception object and immediately throws it with
die
system function.open my $fh, $file or Exception::Base->throw( message=>"Can not open file: $file" );
The
throw
is also exported as a function.open my $fh, $file or throw 'Exception::Base' => message=>"Can not open file: $file";
The throw
can be also used as a method.
-
$obj
->throw([%args])Immediately throws exception object. It can be used for rethrowing existing exception object. Additional arguments will override the attributes in existing exception object.
$e = Exception::Base->new; # (...) $e->throw( message=>"thrown exception with overridden message" ); eval { Exception::Base->throw( message=>"Problem", value=>1 ) }; $@->throw if $@->value;
-
$obj
->throw(message, [%args])If the number of args list for arguments is odd, the first argument is a message. This message can be overridden by message from args list.
Exception::Base->throw( "Problem", message=>"More important" ); eval { die "Bum!" }; Exception::Base->throw( $@, message=>"New message" );
-
CLASS->throw($exception, [%args])
Immediately rethrows an existing exception object as an other exception class.
eval { open $f, "w", "/etc/passwd" or Exception::System->throw }; # convert Exception::System into Exception::Base Exception::Base->throw($@);
-
CLASS->catch([$variable])
The exception is recovered from variable argument or
$@
variable if variable argument was empty. Then also$@
is replaced with empty string to avoid an endless loop.The method returns an exception object if exception is caught or undefined value otherwise.
eval { Exception::Base->throw; }; if ($@) { my $e = Exception::Base->catch; print $e->to_string; }
If the value is not empty and does not contain the
Exception::Base
object, new exception object is created with class CLASS and its message is based on previous value with removed" at file line 123."
string and the last end of line (LF).eval { die "Died\n"; }; my $e = Exception::Base->catch; print ref $e; # "Exception::Base"
-
matches(that)
Checks if the exception object matches the given argument.
The
matches
method overloads~~
smart matching operator. Warning: The second argument for smart matching operator needs to be scalar.If the argument is a reference to array, it is checked if the object is a given class.
use Exception::Base 'Exception::Simple', 'Exception::Complex' => { isa => 'Exception::Simple }; eval { Exception::Complex->throw() }; print $@->matches( ['Exception::Base'] ); # matches print $@->matches( ['Exception::Simple', 'Exception::X'] ); # matches print $@->matches( ['NullObject'] ); # doesn't
If the argument is a reference to hash, attributes of the exception object is matched.
eval { Exception::Base->throw( message=>"Message", value=>123 ) }; print $@->matches( { message=>"Message" } ); # matches print $@->matches( { value=>123 } ); # matches print $@->matches( { message=>"Message", value=>45 } ); # doesn't
If the argument is a single string, regexp or code reference or is undefined, the default attribute of the exception object is matched (usually it is a "message" attribute).
eval { Exception::Base->throw( message=>"Message" ) }; print $@->matches( "Message" ); # matches print $@->matches( qr/Message/ ); # matches print $@->matches( qr/[0-9]/ ); # doesn't print $@->matches( sub{/Message/} ); # matches print $@->matches( sub{0} ); # doesn't print $@->matches( undef ); # doesn't
If argument is a numeric value, the argument matches if
value
attribute matches.eval { Exception::Base->throw( value=>123, message=>456 ) } ); print $@->matches( 123 ); # matches print $@->matches( 456 ); # doesn't
If an attribute contains array reference, the array will be
sprintf
-ed before matching.eval { Exception::Base->throw( message=>["%s", "Message"] ) }; print $@->matches( "Message" ); # matches print $@->matches( qr/Message/ ); # matches print $@->matches( qr/[0-9]/ ); # doesn't
The
match
method matches for special keywords:-
-isa
Matches if the object is a given class.
eval { Exception::Base->new( message=>"Message" ) }; print $@->matches( { -isa=>"Exception::Base" } ); # matches print $@->matches( { -isa=>["X::Y", "Exception::Base"] } ); # matches
-
-has
Matches if the object has a given attribute.
eval { Exception::Base->new( message=>"Message" ) }; print $@->matches( { -has=>"Message" } ); # matches
-
-default
Matches against the default attribute, usually the
message
attribute.eval { Exception::Base->new( message=>"Message" ) }; print $@->matches( { -default=>"Message" } ); # matches
-
-
to_string
Returns the string representation of exception object. It is called automatically if the exception object is used in string scalar context. The method can be used explicitly.
eval { Exception::Base->throw; }; $@->{verbosity} = 1; print "$@"; $@->verbosity = 4; print $@->to_string;
-
to_number
Returns the numeric representation of exception object. It is called automatically if the exception object is used in numeric scalar context. The method can be used explicitly.
eval { Exception::Base->throw( value => 42 ); }; print 0+$@; # 42 print $@->to_number; # 42
-
to_bool
Returns the boolean representation of exception object. It is called automatically if the exception object is used in boolean context. The method can be used explicitly.
eval { Exception::Base->throw; }; print "ok" if $@; # ok print "ok" if $@->to_bool; # ok
-
get_caller_stacktrace
Returns an array of strings or string with caller stack trace. It is implicitly used by
to_string
method. -
PROPAGATE
Checks the caller stack and fills the
propagated_stack
attribute. It is usually used ifdie
system function was called without any arguments. -
_collect_system_data
Collects system data and fills the attributes of exception object. This method is called automatically if exception if thrown or created by
new
constructor. It can be overridden by derived class.package Exception::Special; use base 'Exception::Base'; use constant ATTRS => { %{Exception::Base->ATTRS}, 'special' => { is => 'ro' }, }; sub _collect_system_data { my $self = shift; $self->SUPER::_collect_system_data(@_); $self->{special} = get_special_value(); return $self; } BEGIN { __PACKAGE__->_make_accessors; } 1;
Method returns the reference to the self object.
-
_make_accessors
Creates accessors for each attribute. This static method should be called in each derived class which defines new attributes.
package Exception::My; # (...) BEGIN { __PACKAGE__->_make_accessors; }
-
package
Returns the package name of the subroutine which thrown an exception.
-
file
Returns the file name of the subroutine which thrown an exception.
-
line
Returns the line number for file of the subroutine which thrown an exception.
-
subroutine
Returns the subroutine name which thrown an exception.
= Class Diagram =
+ignore_class : ArrayRef {new} +ignore_level : Int = 0 {new} +ignore_package : ArrayRef {new} +max_arg_len : Int = 64 {new} +max_arg_nums : Int = 8 {new} +max_eval_len : Int = 0 {new} +message : Str|ArrayRef[Str] = "Unknown exception" {new} +value : Int = 0 {new} +verbosity : Int = 2 {new} +caller_stack : ArrayRef +egid : Int +euid : Int +gid : Int +pid : Int +propagated_stack : ArrayRef +tid : Int +time : Int +uid : Int #defaults : HashRef #default_attribute : Str = "message" #numeric_attribute : Str = "value" #eval_attribute : Str = "message" #string_attributes : ArrayRef[Str] = ["message"]
<> +new( args : Hash ) <> +throw( args : Hash = undef ) <> +throw( message : Str, args : Hash = undef ) +catch() : Exception::Base +catch( variable : Any ) : Exception::Base +matches( that : Any ) : Bool {overload="~~"} +to_string() : Str {overload='""'} +to_number() : Num {overload="0+"} +to_bool() : Bool {overload="bool"} +get_caller_stacktrace() : Array[Str]|Str +PROPAGATE() #_collect_system_data() #_make_accessors() {init} #_make_caller_info_accessors() {init} <> +ATTRS() : HashRef ]
Repository: http://github.com/dex4er/perl-Exception-Base
There are more implementation of exception objects available on CPAN. Please note that Perl has built-in implementation of pseudo-exceptions:
eval { die { message => "Pseudo-exception", package => __PACKAGE__,
file => __FILE__, line => __LINE__ };
};
if ($@) {
print $@->{message}, " at ", $@->{file}, " in line ", $@->{line}, ".\n";
}
The more complex implementation of exception mechanism provides more features.
-
Complete implementation of try/catch/finally/otherwise mechanism. Uses nested closures with a lot of syntactic sugar. It is slightly faster than
Exception::Base
module for failure scenario and is much slower for success scenario. It doesn't provide a simple way to create user defined exceptions. It doesn't collect system data and stack trace on error. -
More Perlish way to do OO exceptions. It is similar to
Exception::Base
module and provides similar features but it is 10x slower for failure scenario. -
Additional try/catch mechanism for Exception::Class. It is 15x slower for success scenario.
-
Elegant OO exceptions similar to Exception::Class and
Exception::Base
. It might be missing some features found inException::Base
and Exception::Class. -
Not recommended. Abandoned. Modifies
%SIG
handlers. -
A module which gives new try/catch keywords without source filter.
-
Smaller, simpler and slower version of TryCatch module.
The Exception::Base
does not depend on other modules like
Exception::Class and it is more powerful than Class::Throwable. Also it
does not use closures as Error and does not pollute namespace as
Exception::Class::TryCatch. It is also much faster than
Exception::Class::TryCatch and Error for success scenario.
The Exception::Base
is compatible with syntax sugar modules like
TryCatch and Try::Tiny.
The Exception::Base
is also a base class for enhanced classes:
-
The exception class for system or library calls which modifies
$!
variable. -
The exception class for eval blocks with simple "die" in perlfunc. It can also handle $SIG{__DIE__} hook and convert simple "die" in perlfunc into an exception object.
-
The exception class which handle $SIG{__WARN__} hook and convert simple "warn" in perlfunc into an exception object.
The Exception::Base
module allows to create new exception classes easily.
You can use "import" in perlfunc interface or base module to do it.
The "import" in perlfunc interface allows to create new class with new read-write attributes.
package Exception::Simple;
use Exception::Base (__PACKAGE__) => {
has => qw{ reason method },
string_attributes => qw{ message reason method },
};
For more complex exceptions you can redefine ATTRS
constant.
package Exception::Complex;
use base 'Exception::Base';
use constant ATTRS => {
%{ Exception::Base->ATTRS }, # SUPER::ATTRS
hostname => { is => 'ro' },
string_attributes => qw{ hostname message },
};
sub _collect_system_data {
my $self = shift;
my $hostname = `hostname`;
chomp $hostname;
$self->{hostname} = $hostname;
return $self->SUPER::_collect_system_data(@_);
}
There are two scenarios for "eval" in perlfunc block: success or failure. Success scenario should have no penalty on speed. Failure scenario is usually more complex to handle and can be significantly slower.
Any other code than simple if ($@)
is really slow and shouldn't be used if
speed is important. It means that any module which provides try/catch syntax
sugar should be avoided: Error, Exception::Class::TryCatch, TryCatch,
Try::Tiny. Be careful because simple if ($@)
has many gotchas which are
described in Try::Tiny's documentation.
The Exception::Base
module was benchmarked with other implementations for
simple try/catch scenario. The results
(Perl 5.10.1 x86_64-linux-thread-multi) are following:
-----------------------------------------------------------------------
| Module | Success sub/s | Failure sub/s |
-----------------------------------------------------------------------
| eval/die string | 3715708 | 408951 |
-----------------------------------------------------------------------
| eval/die object | 4563524 | 191664 |
-----------------------------------------------------------------------
| Exception::Base eval/if | 4903857 | 11291 |
-----------------------------------------------------------------------
| Exception::Base eval/if verbosity=1 | 4790762 | 18833 |
-----------------------------------------------------------------------
| Error | 117475 | 26694 |
-----------------------------------------------------------------------
| Class::Throwable | 4618545 | 12678 |
-----------------------------------------------------------------------
| Exception::Class | 643901 | 3493 |
-----------------------------------------------------------------------
| Exception::Class::TryCatch | 307825 | 3439 |
-----------------------------------------------------------------------
| TryCatch | 690784 | 294802 |
-----------------------------------------------------------------------
| Try::Tiny | 268780 | 158383 |
-----------------------------------------------------------------------
The Exception::Base
module was written to be as fast as it is
possible. It does not use internally i.e. accessor functions which are
slower about 6 times than standard variables. It is slower than pure
die/eval for success scenario because it is uses OO mechanisms which are slow
in Perl. It can be a little faster if some features are disables, i.e. the
stack trace and higher verbosity.
You can find the benchmark script in this package distribution.
If you find the bug or want to implement new features, please report it at https://github.com/dex4er/perl-Exception-Base/issues
The code repository is available at http://github.com/dex4er/perl-Exception-Base
Piotr Roszatycki dexter@cpan.org
Copyright (c) 2007-2010, 2012-2013 Piotr Roszatycki dexter@cpan.org.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.