Activator

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lib/Activator/Config.pm  view on Meta::CPAN

command line options

=item *

environment variables

=item *

forced overrides from config files

=item *

merged settings from YAML configuration files

=back

=head1 COMMAND LINE ARGUMENTS

This module allows you to override configuration file settings from
the command line. You can use long or short options using C<'-'> or
C<'--'> notation, allows barewords in any order, and recognizes the
arguments terminator C<'--'>. Also supported are multiple flag
arguments:

  #### turn on super verbosity. sets $config->{v} = 2
  myscript.pl -v -v

You can specify configured options at the command line for
override:

  #### override the configuration file setting for 'foo'
  myscript.pl --foo=bar

Note that while YAML configuration (and this module) support deep
structures for configuration, you can only override top level keys
that are scalars using command line arguments and/or environment
variables.

=head2 Reserved Arguments

There are a few reserved command line arguments:

 --skip_env        : ignore environment variables (EXCEPT $USER)
 --project=<>      : used to search for the C<E<lt>projectE<gt>.yml> file
 --realm=<>        : use C<E<lt>realmE<gt>.yml> in config file processing and
                     consider all command line arguments to be in this realm
 --conf_path       : colon separated list of directories to search for config files

=head2 Project as a Bareword Argument

There are times where a script takes the project name as a required
bareword argument. For these cases, require that project be the last
argument, and pass a flag to L</get_config()>. 

That is, when your script is called like this:

  myscript.pl --options <project>

get the config like this:

  Activator::Config->get_config( \@ARGV, undef, 1 );

The second argument to L</get_config()> is the realm, so you pass
C<undef> (unless you know the realm you are looking for) to allow the
command line options and environment variables to take affect.

=head1 ENVIRONMENT VARIABLES

Environment variables can be used to act as a default to command line
options, and/or override any top level configuration file key which is
a scalar. The expected format is C<ACT_CONFIG_[key]>. Note that YAML is
case sensitive, so the environment variables must match. Be especially
wary of command shell senstive characters in your YAML keys (like
C<:~E<gt>E<lt>|>).

If you wish to override a key for only a particular realm, you
can insert the realm into the env variable wrapped by double
underscores:

 ACT_CONFIG_foo       - set 'foo' for default realm
 ACT_CONFIG__bar__foo - set 'foo' only for 'bar' realm

The L</Reserved Arguments> listed in the L</COMMAND LINE ARGUMENTS>
section also have corresponding environment variables with only
C<skip_env> being slightly different:

 ACT_CONFIG_skip_env     : set to 1 to skip, or 0 (or don't set it at all) to
                        not skip
 ACT_CONFIG_project      : same as command line argument
 ACT_CONFIG_realm        : same as command line argument
 ACT_CONFIG_conf_path    : same as command line argument

=head2 Automatically Imported Environment Variables

Since they tend to be generally useful, the following environment
variables are automatically imported into your configuration:

=over

=item *

HOME

=item *

USER

=back

it is L</FUTURE WORK> to make these cross-platform compatible.

=head1 CONFIGURATION FILES

Currently, you can put your YAML configuration file wherever you like,
but you must set a key inside your configuration files C<conf_path>,
then set the environment variable C<ACT_CONFIG_conf_path> or use the
C<--conf_path> option. It is somewhat wonky the way this currently
works, and it'll get fixed Real Soon Now.

This path behaves the same as a bash shell C<$PATH>, in that you can
set this to one or more colon separated fully qualified path values.
Note that the leftmost path takes precedence when processing config
files.

lib/Activator/Config.pm  view on Meta::CPAN


=over

=item *

All configuration files are read and merged together with higher
precedence configuration files overriding lower precedence on a realm
by realm basis.

If identically named files exist in the C<conf_path> for any level
(user, realm, project, organization), only the first discovered file
is used. Put another way, the leftmost path in the C<conf_path> takes
precedence for any file name conflict.

=item *

The C<default> realm is merged into each realm (I<realm>'s values
taking precedence).

=item *

All C<default> realm environment variables override all values for
each I<realm> (excepting the C<overrides> realm).

=item *

All specific I<realm> environment variables override that realm's values.

=item *

The C<default> realm overrides section is used to override matching
keys in each I<realm>.

=item *

The specific I<realm> overrides section is used to override matching keys
in I<realm>.

=item *

Any command line options given override ALL matching keys for ALL realms.

=item *

# TODO: NOT YET IMPLEMENTED

Perform variable substitution

=back

=head1 METHODS

=cut

sub new {
    my ( $pkg ) = @_;

    my $self = bless( {
		       REGISTRY   => Activator::Registry->new(),
		       ARGV_EXTRA => {},
		       ARGV       => undef,
		       BAREWORDS  => undef,
		      }, $pkg);

    $self->_init_StrongSingleton();

    return $self;
}

=head2 get_config()

Process command line arguments, environment variables and
configuration files then return a hashref representing the merged
configuration. Recognized configuration items are removed from C<@ARGV>.

Usage:
  Activator::Config->get_config( \@ARGV, $realm, $project_is_arg );


C<$realm> is optional (default is 'default'). If undefined, it will be
determined from a command line option or environment variable.

C<$project_is_arg> is optional. Use any true value for this argument
if your script requries the project name as the last bareword
argument.

Examples:

  #
  # get options for default realm
  #
  my $config = Activator::Config->get_config( \@ARGV );

  #
  # get options for 'some' realm, ignoring --realm and ACT_CONFIG_realm
  #
  my $config = Activator::Config->get_config( \@ARGV, 'some' );

  #
  # don't ignore --realm and ACT_CONFIG_realm, use $barewords[-1] (the
  # last bareword argument) as the project
  #
  Activator::Config->get_config( \@ARGV, undef, 1 );

See L</get_args()> for a description of the way command line arguments
are processed.

If called repeatedly, this sub does NOT reprocess C<\@ARGV>. This
allows you to make multiple calls to get a reference to the config for
multiple realms if desired.

=cut

sub get_config {
    my ( $pkg, $argv, $realm, $project_is_arg ) = @_;
    my $self = &new( @_ );

    # get_args sets $self->{ARGV}
    $self->get_args( $argv );
    DEBUG( Data::Dumper->Dump( [ $self->{ARGV} ], [ qw/ ARGV / ] ) );
    DEBUG( Data::Dumper->Dump( [ $self->{BAREWORDS} ], [ qw /BAREWORDS/ ] ) );

    # make sure we can use ENV vars
    my $skip_env =  $ENV{ACT_CONFIG_skip_env};

    $realm ||=
      $self->{ARGV}->{realm} ||
	( $skip_env ? undef : $ENV{ACT_CONFIG_realm} ) ||
	  'default';

    if ( ref( $realm ) ) {
	Activator::Exception::Config->throw( 'realm_specified_more_than_once', Dumper( $realm ) );
    }

    if ( $realm ne 'default' ) {
	Activator::Registry->set_default_realm( $realm );
    }

    # setup or get the merged YAML configuration settings from files
    # into the registry
    my $config = $self->{REGISTRY}->get_realm( $realm );

    # first call
    if ( !keys %$config ) {
	# define valid config from config files
	try eval {
	    $self->_process_config_files( $realm, $skip_env, $project_is_arg );
	};
	if ( catch my $e ) {
	    $e->rethrow;
	}

	# read environment variables, set any keys found
	if ( !$skip_env ) {
	    my ( $env_key, $env_realm );
	    foreach my $env_key ( keys %ENV ) {
		next unless $env_key =~ /^ACT_CONFIG_(.+)/;
		$opt_key = $1;
		$opt_realm = $realm;

		my $env_opt_realm = $opt_realm;
		my $env_opt_key = $opt_key;
		if ( $opt_key =~ /^_(\w+)__(\w+)$/ ) {
		    $env_opt_realm = $1;
		    $env_opt_key = $2;
		    if ( $env_opt_realm eq $realm ) {
			$opt_key = $env_opt_key;
			$opt_realm = $env_opt_realm;
		    }
		}

		if ( $self->{REGISTRY}->get( $opt_key, $opt_realm ) ) {
		    $self->{REGISTRY}->register( $opt_key, $ENV{ $env_key }, $opt_realm );
		}
		elsif( $env_opt_realm ne $opt_realm &&
		      !grep( /$opt_key/, qw( skip_env project
					     realm conf_path ) ) ) {
		    WARN( "Skipped invalid environment variable $env_key.  Key '$opt_key' for realm '$opt_realm' unchanged");
		}
	    }
	}

	# forced overrides from config files
	my $overrides = $self->{REGISTRY}->get_realm( 'overrides' );
	DEBUG( Data::Dumper->Dump( [ $overrides ], [ 'processing overrides' ] ) );

	# NOTE: bad (typo) keys could be in overrides. Someday,
	# Activator::Registry will allow debug mode so we can

lib/Activator/Config.pm  view on Meta::CPAN

Arguments can be barewords, '-' notation or '--' notation.

=item *

Any arguments after the arguments terminator symbol (a plain '--'
argument) are returned as barewords. Bareword order of specification
is maintained.

=item *

Values with spaces must be double-quoted, and can themselves contain quotes

  --mode="sliding out of control"
  --plan="pump the "brakes" vigorously"

=item *

Flag arguments are counted. That is C<-v -v> would set C<$config-E<gt>{v} = 2>

=item *

Argument bundling is not supported.

=back

Examples:

  @ARGV                | Value returned
 ----------------------+-----------------------------------------
  --arg                | $argv = { arg => 1 }
  --arg --arg          | $argv = { arg => 2 }
  --arg=val            | $argv = { arg => 'val' }
  --arg=val --arg=val2 | $argv = { arg => [ 'val', 'val2' ] }
  --arg="val val"      | $argv = { arg => 'val val' }

Returns array: C<( $args_hashref, $barewords_arrayref )>

Throws C<Activator::Exception::Config> when arg is invalid (which at this
time is only when a barewod arg of '=' is detected).

=cut

sub get_args {
    my ( $pkg, $argv_raw ) = @_;
    my $self = &new( @_ );

    # quick and dirty check for debug mode
    if( grep /^--?debug$/, @$argv_raw ) {
	Activator::Log->level('DEBUG');
	DEBUG('Entering debug mode');
    }

    if ( defined( $self->{ARGV} ) || defined( $self->{BAREWORDS} ) ) {
	DEBUG("skipping ARGV reprocessing");
	return ( $self->{ARGV}, $self->{BAREWORDS} );
    }

    DEBUG("got ARGV: ". join(' ', @$argv_raw ));

    # use refs to insure that that $self->{ARGV} and
    # $self->{BAREWORDS} are defined, so we don't return undef.
    my $argv = {};
    my $barewords = [];
    my $found_terminator = 0;

    foreach my $arg ( @$argv_raw ) {
	my ( $key, $value ) = $self->_get_arg( $arg );

	if ( $found_terminator || !defined( $key ) ) {
	    DEBUG("'$arg' is a bareword or after the args terminator '--'");
	    push @$barewords, $arg;
            next;
	}

	if( $key eq '--' ) {
	    DEBUG("'$arg' is the terminator");
	    $found_terminator = 1;
	    next;
	}

        if ( defined $value ) {
	    DEBUG("got key '$key' = '$value'");

	    # if we see an argument again, coerce this value into an
	    # array
            if ( exists $argv->{ $key } ) {
		if ( reftype ( $argv->{ $key } ) eq 'ARRAY' ) {
		    DEBUG("added '$value' to key list '$key'" );
		    push @{ $argv->{ $key } }, $value;
		}
		else {
		    DEBUG("created key list '$key' and added '$value'" );
		  $argv->{ $key } = [ $argv->{ $key }, $value ];
	      }
	    }
	    # just set it
	    else {
		$argv->{ $key } = $value;
	    }
	}
        else {

	    # if we see a value again, increment the occurence count
	    if ( exists $argv->{ $key } ) {
		DEBUG("incremented key '$key'" );
		$argv->{ $key }++;
	    }
	    else {
		DEBUG("set $key" );
		$argv->{ $key } = 1;
	    }
        }
    }

    # save these so we don't have to do it again
    $self->{ARGV}      = $argv;
    $self->{BAREWORDS} = $barewords;

    return ( $argv, $barewords );
}

# Helper to split an arg into key/value. Returns ($key, $value), where
# $value is undef if the argument is flag format (--debug), undef if
# it is a bareword ( foo ) and '--' if it is the arguments terminator
# symbol.
#
sub _get_arg {
    my ( $self, $arg ) = @_;

    if ( $arg !~ /^-(-)?/ ) {
	return;
    }

    if ( $arg eq '--' ) {
	return $arg;
    }

    my ( $key, $value ) = split /=/xms, $arg, 2;

    if ( !defined $key ) {
	Activator::Exception::Config->throw( 'argument',
					      'invalid',
					      $arg );
    }

    # clean up key
    $key =~ s/^--?//;

    # clean up value, if quoted
    if ( defined $value ) {
	$value =~ s/^"//;
	$value =~ s/"$//;
    }

    return ( $key, $value );
}

# Merge config files into this objects Activator::Registry object
sub _process_config_files {
    my ( $pkg, $realm, $skip_env, $project_is_arg ) = @_;
    my $self = &new( @_ );

    # figure out what project we are working on
    my $project =
      $self->{ARGV}->{project} ||
	( $project_is_arg ? $self->{BAREWORDS}->[-1] : undef ) ||
	  ( $skip_env ? undef : $ENV{ACT_CONFIG_project} ) ||
	    Activator::Exception::Config->throw( 'project', 'missing' );

    # process these files:
    #     $ENV{USER}.yml
    #     <realm>.yml    - realm specific settings and defaults
    #     <project>.yml  - project specific settings and defaults
    #     org.yml        - top level organization settings and defaults
    # in one of these paths, if set
    #   --conf_file=       : use $self->{ARGV}->{conf_file} (which could be an arrayref )
    #   ACT_CONFIG_conf_file= : comma separated list of files

    my $conf_path = $self->{ARGV}->{conf_path};
    if ( ! $conf_path ) {
	$conf_path = ( $skip_env ? undef : $ENV{ACT_CONFIG_conf_path} );
	if ( !$conf_path ) {
	    ERROR( "Neither ACT_CONFIG conf_path env var nor --conf_path set");
	    Activator::Exception::Config->throw( 'conf_path', 'missing' );
	}
	else {
	    INFO( "Using ACT_CONFIG_conf_path env var: $conf_path");
	}
    }
    else {
	INFO( "Using conf_path argument: $conf_path");
    }

    my @search_paths = split ':', $conf_path;
    DEBUG( 'Searching for conf files in: ' . Data::Dumper->Dump( [ \@search_paths ], [ qw/ search_paths / ] ) );

    # Search for these files, create a files lookup.
    my $files = { user    => { target => "$ENV{USER}.yml" },
		  realm   => { target => "${realm}.yml"   },
		  project => { target => "${project}.yml" },
		  org     => { target => 'org.yml' } };

    foreach my $path ( @search_paths ) {
	$path =~ s|/$||;
	foreach my $which ( keys %$files ) {
	    my $target = $files->{ $which }->{target};

	    if ( !opendir DIR, $path ) {
		WARN( "Ignoring invalid path '$path'" );
	    } else {
		my @found = grep { /^$target$/ && -f "$path/$_" } readdir(DIR);
		if ( @found  ) {
		    my $file = "$path/$found[0]";
		    if ( !exists( $files->{ $which }->{ file } ) ) {
			$files->{ $which }->{file} = $file;
		    } else {
			INFO( "Ignoring lower priority config file '$file'" );
		    }
		}
	    }
	}
    }

    DEBUG ( 'Processing config files: ' . Data::Dumper->Dump( [ $files ], [ qw/ files / ] ) );

    # now that we have all the files, import 'em! This is a super long
    # winded but safe "left precedence" merge of all files
    my ( $user_config, $realm_config, $project_config, $org_config );

    try eval {
	if ( exists( $files->{user}->{file} ) ) {
	    $user_yml = YAML::Syck::LoadFile( $files->{user}->{file} );
	}
    };
    if ( catch my $e ) {
	Activator::Exception::Config->throw( 'user_config', 'invalid', $e );
    }

    try eval {
	if ( exists( $files->{realm}->{file} ) ) {
	    $realm_yml = YAML::Syck::LoadFile( $files->{realm}->{file} );



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