This config loader offers a couple of major features that make it
compelling for the user:
1. Object based configuration
This is a huge deal. This means that you can trivially set defaults,
add validation, and an other number of cool things. On top of that
this means that unless you do something silly, your configuration has
clearly defined fields, instead of being a shapeless hash.
2. Environment based overriding
Presumably many users of this module will be loading their config
from a file. That's fine and normal, but baked into the module is and
an environment based config solution. This allows the user to change,
for example, a port, by just running the application as follows:
MYAPP_WWW_PORT=8080 perl bin/myapp.pl
ATTRIBUTES
my $station = Config::Station->new( env_key => 'MYAPP' )
env_key
The env_key is a required attribute which affects everything about this
module.
env_key affects two classes of values:
Meta Configuration
These values use the env_key as a suffix, and are documented further
down.
Normal Configuration
These values use the env_key as a prefix for env vars that override
configuration keys. To be clear, if you specify an env_key of FOO, an
env var of FOO_BAR=BAZ will pass bar => 'BAZ' to the constructor of
"config_class".
config_class
The config_class is a required attribute which determines the class
that will be used when loading the configuration. The config class
absolutely must have a new method which takes a hash. What it returns
is up to you.
If you care to, you can define a serialize method on the object which
supports the "store" method, but I suspect that is likely not a typical
use case.
debug
Debugging is critical feature of this module. If you set this attribute
directly, or indirectly by setting the env var 'DEBUG_' . $env_key, you
will get some handy debugging output warned. It looks like this:
CONFIGSTATION FROM FILE:
name: herp
CONFIGSTATION FROM ENV:
id: 1
name: wins
If the file can't be loaded or parsed, for some reason, instead of
listing key-value pairs, the output for the file will be:
CONFIGSTATION FROM FILE: $exception
Note that failure to load or deserialize the file is not considered an
error. If you want to enforce that data is set do that by making your
object constructor more strict.
location
The location can be set directly, or indirectly by setting the env var
'FILE_' . $env_key. As noted above, it is neither required to be set or
parseable at all.
decode_via
my $station = Config::Station->new( ..., decode_via => sub { \&YAML::Load );
A code reference which can inflate a string into a hash reference.
Default uses JSON.
encode_via
my $station = Config::Station->new( ..., encode_via => sub { \&YAML::Dump );
A code reference which can deflate a hash reference into a string.
Default uses JSON.
