Name

App::Sqitch::X - Sqitch Exception class

Synopsis

Throw:

  use Locale::TextDomain;
  use App::Sqitch::X;
  open my $fh, '>', 'foo.txt' or App::Sqitch::X->throw(
      ident   => 'io',
      message => __x 'Cannot open {file}: {err}", file => 'foo.txt', err => $!,
  );

Hurl:

  use App::Sqitch::X qw(hurl);
  open my $fh, '>', 'foo.txt' or hurl {
      ident   => 'io',
      message => __x 'Cannot open {file}: {err}", file => 'foo.txt', err => $!,
  };

Developer:

  hurl 'Odd number of arguments passed to burf()' if @_ % 2;

Description

This module provides implements Sqitch exceptions. Exceptions may be thrown by any part of the code, and, as long as a command is running, they will be handled, showing the error message to the user.

Interface

Class Method

throw()

  open my $fh, '>', 'foo.txt' or App::Sqitch::X->throw(
      ident   => 'io',
      message => __x 'Cannot open {file}: {err}", file => 'foo.txt', err => $!,
  );

Throws an exception. The supported parameters include:

ident

A non-localized string identifying the type of exception.

message

The exception message. Use Locale::TextDomain to craft localized messages.

exitval

Suggested exit value to use. Defaults to 2. This will be used if Sqitch handles an exception while a command is running.

Function

hurl

To save yourself some typing, you can import the hurl keyword and pass the parameters as a hash reference, like so:

  use App::Sqitch::X qw(hurl);
  open my $fh, '>', 'foo.txt' or hurl {
      ident   => 'io',
      message => __x 'Cannot open {file}: {err}", file => 'foo.txt', err => $!,
  };

More simply, if all you need to pass are the ident and message parameters, you can pass them as the only arguments to hurl():

  open my $fh, '>', 'foo.txt'
    or hurl io => __x 'Cannot open {file}: {err}", file => 'foo.txt', err => $!

For errors that should only happen during development (e.g., an invalid parameter passed by some other library that should know better), you can omit the ident:

  hurl 'Odd number of arguments passed to burf()' if @_ % 2;

In this case, the ident will be DEV, which you should not otherwise use. Sqitch will emit a more detailed error message, including a stack trace, when it sees DEV exceptions.

Methods

as_string

  my $errstr = $x->as_string;

Returns the stringified representation of the exception. This value is also used for string overloading of the exception object, which means it is the output shown for uncaught exceptions. Its contents are the concatenation of the exception message, the previous exception (if any), and the stack trace.

Handling Exceptions

use Try::Tiny to do exception handling, like so:

  use Try::Tiny;
  try {
      # ...
  } catch {
      die $_ unless eval { $_->isa('App::Sqitch::X') };
      $sqitch->vent($x_->message);
      if ($_->ident eq 'DEV') {
          $sqitch->vent($_->stack_trace->as_string);
      } else {
          $sqitch->debug($_->stack_trace->as_string);
      }
      exit $_->exitval;
  };

Use the ident attribute to determine what category of exception it is, and take changes as appropriate.

Author

David E. Wheeler <david@justatheory.com>

License

Copyright (c) 2012 iovation Inc.

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

cpanm App::Sqitch

perl -MCPAN -e shell
install App::Sqitch