Config.pm

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=pod 
 
=head1 NAME
 
    Bio::EnsEMBL::Hive::Utils::Config
 
=head1 DESCRIPTION
 
    A parser for JSON-based configuration files mainly used in scheduling and graph generation.
 
=head1 LICENSE
 
    Copyright [1999-2015] Wellcome Trust Sanger Institute and the EMBL-European Bioinformatics Institute
    Copyright [2016-2024] EMBL-European Bioinformatics Institute
 
    Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License.
    You may obtain a copy of the License at
 
         http://www.apache.org/licenses/LICENSE-2.0
 
    Unless required by applicable law or agreed to in writing, software distributed under the License
    is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and limitations under the License.
 
=head1 CONTACT
 
    Please subscribe to the Hive mailing list:  http://listserver.ebi.ac.uk/mailman/listinfo/ehive-users  to discuss Hive-related questions or to be notified of our updates
 
=cut
 
 
package Bio::EnsEMBL::Hive::Utils::Config;
 
use strict;
use warnings;
use JSON;
use Bio::EnsEMBL::Hive::Utils ('throw');
 
 
sub default_system_config {
    my $ehive_root_dir = $ENV{'EHIVE_ROOT_DIR'}
        or throw("ENV{EHIVE_ROOT_DIR} is not defined");
 
    return $ehive_root_dir.'/hive_config.json';
}
 
 
sub default_user_config {
    return $ENV{'HOME'}.'/.hive_config.json';
}
 
 
sub default_config_files {  # a class method, returns a list
    my $self = shift @_;
 
    my $system_config   = $self->default_system_config;
    my $user_config     = $self->default_user_config;
 
    return ($system_config, (-r $user_config) ? ($user_config) : ());
}
 
 
sub new {
    my $class = shift @_;
 
    my $self = bless {}, $class;
    $self->config_hash( {} );
 
    foreach my $cfg_file ( scalar(@_) ? @_ : $self->default_config_files ) {
        if(my $cfg_hash = $self->load_from_json($cfg_file)) {
            $self->merge($cfg_hash);
        }
    }
 
    return $self;
}
 
 
sub config_hash {
    my $self = shift @_;
 
    if(@_) {
        $self->{_config_hash} = shift @_;
    }
    return $self->{_config_hash};
}
 
 
sub load_from_json {
    my ($self, $filename) = @_;
 
    if(-r $filename) {
        my $json_text   = `cat $filename`;
        my $json_parser = JSON->new->relaxed;
        my $perl_hash   = $json_parser->decode($json_text);
        
        return $perl_hash;
    } else {
        warn "Can't read from '$filename'. Configuration file not loaded\n";
 
        return undef;
    }
}
 
 
sub merge {
    my $self = shift @_;
    my $from = shift @_;
    my $to   = shift @_ || $self->config_hash;  # only defined in subsequent recursion steps
 
    if(ref($from) eq 'HASH') {      # FIXME: currently we don't merge ARRAY references (the only example we currently have is REMARK), only the HASH references
        while(my ($key,$value) = each %$from) {
            if(exists $to->{$key} and ref($to->{$key})) {
                $self->merge($from->{$key}, $to->{$key});
            } else {
                $to->{$key} = $from->{$key};
            }
        }
    }
}
 
 
sub get {
    my $self        = shift @_;
    my $option_name = pop @_;
 
    my $hash_ptr    = $self->config_hash;
    my $option_value = $hash_ptr->{$option_name};   # not necessatily defined
 
    foreach my $context_syll (@_) {
        $hash_ptr = $hash_ptr->{$context_syll};
        if(exists $hash_ptr->{$option_name}) {
            $option_value = $hash_ptr->{$option_name};
        }
    }
 
    return $option_value;
}
 
 
sub set {
    my $self        = shift @_;
    my $value       = pop @_;
    my $key         = pop @_;
 
    my $hash_ptr    = $self->config_hash;
 
    foreach my $context_syll (@_) {
        unless(exists $hash_ptr->{$context_syll}) {
            $hash_ptr->{$context_syll} = {};
        }
        $hash_ptr = $hash_ptr->{$context_syll};
    }
 
    if(ref($hash_ptr->{$key}) ne ref($value)) {
        die "Mismatch of types in Config::set(".join(',',@_,$key,$value).") : trying to set a ".(ref($value)||'scalar')." instead of ".ref($hash_ptr->{$key});
    } else {
        $hash_ptr->{$key} = $value;
    }
}
 
1;