AWS-CLIWrapper

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lib/AWS/CLIWrapper.pm  view on Meta::CPAN

Third arg "opt" is optional. Available key/values are below:

  timeout => Int
    Maximum time the "aws" command is allowed to run before aborting.
    default is 30 seconds, unless overridden with AWS_CLIWRAPPER_TIMEOUT environment variable.

  nofork => Int (>0)
    Call IPC::Cmd::run vs. IPC::Cmd::run_forked (mostly useful if/when in perl debugger).  Note: 'timeout', if used with 'nofork', will merely cause an alarm and return.  ie. 'run' will NOT kill the awscli command like 'run_forked' will.

  croak_on_error => Int (>0)
    When set to a truthy value, this will make AWS::CLIWrapper to croak() with error message when `aws` command exits with non-zero status. Default behavior is to set $AWS::CLIWrapper::Error and return.

  catch_error_pattern => RegExp
    When defined, this option will enable catching `aws-cli` errors matching this pattern
    and retrying `aws-cli` command execution. Environment variable
    AWS_CLIWRAPPER_CATCH_ERROR_PATTERN takes precedence over this option, if both
    are defined.

    Default is undef.

  catch_error_retries => Int (>= 0)
    When defined, this option will set the number of retries to make when `aws-cli` error
    was caught with catch_error_pattern, before giving up. Environment variable
    AWS_CLIWRAPPER_CATCH_ERROR_RETRIES takes precedence over this option, if both
    are defined.

    0 (zero) retries is a valid way to turn off error catching via environment variable
    in certain scenarios. Negative values are invalid and will be reset to default.

    Default is 3.

  catch_error_min_delay => Int (>= 0)
    When defined, this option will set the minimum delay in seconds before attempting
    a retry of failed `aws-cli` execution when the error was caught. Environment variable
    AWS_CLIWRAPPER_CATCH_ERROR_MIN_DELAY takes precedence over this option, if both
    are defined.

    0 (zero) is a valid value. Negative values are invalid and will be reset to default.

    Default is 3.

  catch_error_max_delay => Int (>= 0)
    When defined, this option will set the maximum delay in seconds before attempting
    a retry of failed `aws-cli` execution. Environment variable AWS_CLIWRAPPER_CATCH_ERROR_MAX_DELAY
    takes precedence over this option, if both are defined.

    0 (zero) is a valid value. Negative values are invalid and will be reset to default.
    If catch_error_min_delay is greater than catch_error_max_delay, both are set
    to catch_error_min_delay value.

    Default is 10.

=back

=head1 ENVIRONMENT

=over 4

=item HOME: used by default by /usr/bin/aws utility to find it's credentials (if none are specified)

Special note: cron on Linux will often have a different HOME "/" instead of "/root" - set $ENV{'HOME'}
to use the default credentials or specify $ENV{'AWS_CONFIG_FILE'} directly.

=item AWS_CLIWRAPPER_TIMEOUT

If this variable is set, this value will be used instead of default timeout (30 seconds) for every
invocation of `aws-cli` that does not have a timeout value provided in the options argument of the
called function.

=item AWS_CLIWRAPPER_CATCH_ERROR_PATTERN

If this variable is set, AWS::CLIWrapper will retry `aws-cli` execution if stdout output
of failed `aws-cli` command matches the pattern. See L<ERROR HANDLING>.

=item AWS_CLIWRAPPER_CATCH_ERROR_RETRIES

How many times to retry command execution if an error was caught. Default is 3.

=item AWS_CLIWRAPPER_CATCH_ERROR_MIN_DELAY

Minimal delay before retrying command execution if an error was caught, in seconds.

lib/AWS/CLIWrapper.pm  view on Meta::CPAN

=item AWS_DEFAULT_REGION

See documents of aws-cli.

=back

=head1 ERROR HANDLING

=over 4

By default, when `aws-cli` exits with an error code (> 0), AWS::CLIWrapper will set
the error code and message to $AWS::CLIWrapper::Error (and optionally croak), thus
relaying the error to calling code. While this approach is beneficial 99% of the time,
in some use cases `aws-cli` execution fails for a temporary reason unrelated to
both calling code and AWS::CLIWrapper, and can be safely retried after a short delay.

One of this use cases is executing `aws-cli` on AWS EC2 instances, where `aws-cli`
retrieves its configuration and credentials from the API exposed to the EC2 instance;
at certain times these credentials may be rotated and calling `aws-cli` at exactly
the right moment will cause it to fail with `Unable to locate credentials` error.

lib/AWS/CLIWrapper.pm  view on Meta::CPAN

=cut

# for Emacsen
# Local Variables:
# mode: cperl
# cperl-indent-level: 4
# indent-tabs-mode: nil
# coding: utf-8
# End:

# vi: set ts=4 sw=4 sts=0 et ft=perl fenc=utf-8 ff=unix :

t/03_awscli_timeout.t  view on Meta::CPAN

  my $aws = AWS::CLIWrapper->new();

  is $aws->{timeout}, 30, "default timeout is 30 seconds";
}

{
  local $ENV{AWS_CLIWRAPPER_TIMEOUT} = 3600;

  my $aws = AWS::CLIWrapper->new();

  is $aws->{timeout}, 3600, "timeout set via env variable";
}

done_testing;