Add configuration support.

Build.PL

@@ -12,10 +12,14 @@ Module::Build->new(
         'Module::Build'        => '0.35',
         'Test::MockModule'     => '0.05',
         'Test::More'           => '0.17',
+        'File::Spec'           => 0,
     },
     requires => {
         'Class::Accessor::Fast' => '0.31',
+        'Config::INI::Reader'   => 0,
+        'File::HomeDir'         => 0,
         'Getopt::Long'          => 0,
+        'Path::Class'           => 0,
     },
     recommends         => {
         'Test::Pod'  => '1.41',

lib/App/Sqitch.pm

@@ -145,6 +145,53 @@ sub _pod2usage {
     );
 }
 
+sub _global_config_root {
+    require Path::Class;
+    return Path::Class::dir($ENV{SQITCH_GLOBAL_CONFIG_ROOT})
+        if $ENV{SQITCH_GLOBAL_CONFIG_ROOT};
+
+    require File::HomeDir;
+    my $homedir = File::HomeDir->my_home
+        or croak("Could not determine home directory");
+
+    return Path::Class::dir($homedir)->subdir('.sqitch');
+}
+
+sub _load_config {
+    my $self = shift;
+
+    # Read the local and global configs.
+    my $local  = $self->_read_ini('sqitch.ini');
+    my $global = $self->_read_ini( $self->_global_config_root->file('config.ini') );
+
+    if ($global && $local) {
+        # Merge them.
+        for my $section (keys %{ $local }) {
+            if ($global->{$section}) {
+                # Merge the section.
+                $global->{$section} = {
+                    %{ $global->{$section} },
+                    %{ $local->{$section}  },
+                };
+            } else {
+                # Copy the section whole-hog.
+                $global->{$section} = $local->{$section};
+            }
+        }
+        return $global;
+    } else {
+        # Return whatever we've got.
+        return $global || $local || {};
+    }
+}
+
+sub _read_ini {
+    my ($self, $file) = @_;
+    return unless -f $file;
+    require Config::INI::Reader;
+    return Config::INI::Reader->read_file($file);
+}
+
 1;
 
 __END__

t/config.ini

@@ -0,0 +1,11 @@
+[core.pg]
+    client    = /opt/local/pgsql/bin/psql
+    username  = postgres
+    host      = localhost
+
+[core.mysql]
+    client    = /opt/local/mysql/bin/mysql
+    username  = root
+
+[core.sqlite]
+    client    = /opt/local/bin/sqlite3

t/config.t

@@ -0,0 +1,98 @@
+#!/usr/bin/perl -w
+
+use strict;
+use warnings;
+use Test::More tests => 5;
+#use Test::More 'no_plan';
+use File::Spec;
+
+my $CLASS;
+BEGIN {
+    $CLASS = 'App::Sqitch';
+    use_ok $CLASS or die;
+}
+
+is_deeply $CLASS->_load_config, {},
+    'Should have no config by default';
+
+my $config_ini = {
+    'core.pg' => {
+        client   => '/opt/local/pgsql/bin/psql',
+        username => 'postgres',
+        host     => 'localhost',
+    },
+    'core.mysql' => {
+        client   => '/opt/local/mysql/bin/mysql',
+        username => 'root',
+    },
+    'core.sqlite' => {
+        client => '/opt/local/bin/sqlite3',
+    }
+};
+
+# Test loding the global config.
+GLOBAL: {
+    local $ENV{SQITCH_GLOBAL_CONFIG_ROOT} = 't';
+    is_deeply $CLASS->_load_config, $config_ini,
+        'Should load config.ini for global config';
+}
+
+my $sqitch_ini = {
+    "core" => {
+        db        => "widgetopolis",
+        engine    => "pg",
+        extension => "ddl",
+        sql_dir   => "migrations",
+    },
+    "core.pg" => {
+        client   => "/usr/local/pgsql/bin/psql",
+        username => "theory",
+    },
+    "revert" => {
+        to => "gamma",
+    },
+    "bundle" => {
+        dest_dir  => "_build/sql",
+        from      => "gamma",
+        tags_only => "yes",
+    },
+};
+
+chdir 't';
+# Test loading local file.
+is_deeply $CLASS->_load_config, $sqitch_ini,
+    'Should load sqitch.ini for local config';
+
+my $both_ini = {
+    "core" => {
+        db        => "widgetopolis",
+        engine    => "pg",
+        extension => "ddl",
+        sql_dir   => "migrations",
+    },
+    "core.pg" => {
+        client   => "/usr/local/pgsql/bin/psql",
+        username => "theory",
+        host     => 'localhost',
+    },
+    'core.mysql' => {
+        client   => '/opt/local/mysql/bin/mysql',
+        username => 'root',
+    },
+    'core.sqlite' => {
+        client => '/opt/local/bin/sqlite3',
+    },
+    "revert" => {
+        to => "gamma",
+    },
+    "bundle" => {
+        dest_dir  => "_build/sql",
+        from      => "gamma",
+        tags_only => "yes",
+    },
+};
+
+# Test merging.
+$ENV{SQITCH_GLOBAL_CONFIG_ROOT} = File::Spec->curdir;
+is_deeply $CLASS->_load_config, $both_ini,
+    'Should merge both ini files with both present';

t/sqitch.ini

@@ -0,0 +1,17 @@
+[core]
+    engine    = pg
+    db        = widgetopolis
+    sql_dir   = migrations
+    extension = ddl
+
+[core.pg]
+    client    = /usr/local/pgsql/bin/psql
+    username  = theory
+
+[revert]
+    to        = gamma
+
+[bundle]
+    from      = gamma
+    tags_only = yes
+    dest_dir  = _build/sql