NAME

Rewire - Dependency Injection

ABSTRACT

Dependency Injection Container for Perl 5

SYNOPSIS

  use Rewire;

  my $services = {
    filetemp => {
      package => 'File/Temp'
    },
    tempfile => {
      package => 'Mojo/File',
      argument => { '$service' => 'filetemp' }
    }
  };

  my $rewire = Rewire->new(services => $services);

  $rewire->resolve('tempfile');

DESCRIPTION

This package provides methods for using dependency injection, and building objects and values.

INTEGRATES

This package integrates behaviors from:

Data::Object::Role::Buildable

Data::Object::Role::Proxyable

LIBRARIES

This package uses type constraints from:

Types::Standard

SCENARIOS

This package supports the following scenarios:

$callback

  use Rewire;

  my $services = {
    io => {
      package => 'IO/Handle'
    },
    log => {
      package => 'Mojo/Log',
      argument => {
        format => { '$callback' => 'io' }
      }
    },
  };

  my $rewire = Rewire->new(
    services => $services
  );

This package supports resolving services as callbacks to be passed around and/or resolved by other services. The $callback directive is used to specify the name of a service to be resolved and passed as an argument.

$envvar

  use Rewire;

  my $services = {
    file => {
      package => 'Mojo/File',
      argument => { '$envvar' => 'home' }
    }
  };

  my $rewire = Rewire->new(
    services => $services
  );

This package supports inlining environment variables as arguments to services. The $envvar directive is used to specify the name of an environment variable, and can also be used in metadata for reusability.

$function

  use Rewire;

  my $services = {
    temp => {
      package => 'File/Temp'
    },
    file => {
      package => 'Mojo/File',
      argument => { '$function' => 'temp#tempfile' }
    }
  };

  my $rewire = Rewire->new(
    services => $services
  );

This package supports inlining the result of a service resolution and function call as arguments to services. The # delimited $function directive is used to specify the name of an existing service on the right-hand side, and an arbitrary function to be call on the result on the left-hand side.

$metadata

  use Rewire;

  my $metadata = {
    home => '/home/ubuntu'
  };

  my $services = {
    file => {
      package => 'Mojo/File',
      argument => { '$metadata' => 'home' }
    }
  };

  my $rewire = Rewire->new(
    metadata => $metadata,
    services => $services
  );

This package supports inlining configuration data as arguments to services. The $metadata directive is used to specify the name of a stashed configuration value or data structure.

$method

  use Rewire;

  my $services = {
    temp => {
      package => 'File/Temp'
    },
    file => {
      package => 'Mojo/File',
      argument => { '$method' => 'temp#filename' }
    }
  };

  my $rewire = Rewire->new(
    services => $services
  );

This package supports inlining the result of a service resolution and method call as arguments to services. The # delimited $method directive is used to specify the name of an existing service on the right-hand side, and an arbitrary method to be call on the result on the left-hand side.

$routine

  use Rewire;

  my $services = {
    temp => {
      package => 'File/Temp'
    },
    file => {
      package => 'Mojo/File',
      argument => { '$routine' => 'temp#tempfile' }
    }
  };

  my $rewire = Rewire->new(
    services => $services
  );

This package supports inlining the result of a service resolution and routine call as arguments to services. The # delimited $routine directive is used to specify the name of an existing service on the right-hand side, and an arbitrary routine to be call on the result on the left-hand side.

$service

  use Rewire;

  my $services = {
    io => {
      package => 'IO/Handle'
    },
    log => {
      package => 'Mojo/Log',
      argument => {
        handle => { '$service' => 'io' }
      }
    },
  };

  my $rewire = Rewire->new(
    services => $services
  );

This package supports inlining resolved services as arguments to other services. The $service directive is used to specify the name of a service to be resolved and passed as an argument.

arguments

  use Rewire;

  my $metadata = {
    applog => '/var/log/rewire.log'
  };

  my $services = {
    mojo_log => {
      package => 'Mojo/Log',
      argument => {
        path => { '$metadata' => 'applog' },
        level => 'warn'
      },
      argument_as => 'list'
    }
  };

  my $rewire = Rewire->new(
    services => $services,
    metadata => $metadata
  );

This package supports providing static and/or dynamic arguments during object construction from metadata or other services.

builder

  use Rewire;

  my $services = {
    mojo_date => {
      package => 'Mojo/Date',
      builder => [
        {
          method => 'new',
          return => 'self'
        },
        {
          method => 'to_datetime',
          return => 'result'
        }
      ]
    }
  };

  my $rewire = Rewire->new(
    services => $services,
  );

This package supports specifying multiple build steps as function, method, and routine calls and chaining them together.

config

  use Rewire;

  my $metadata = {
    home => '/home/ubuntu'
  };

  my $services = {
    tempfile => {
      package => 'Mojo/File',
      argument => { '$metadata' => 'home' }
    }
  };

  my $rewire = Rewire->new(
    services => $services,
    metadata => $metadata
  );

This package supports configuring services and metadata in the service of building objects and values.

constructor

  use Rewire;

  my $services = {
    mojo_date => {
      package => 'Mojo/Date',
      constructor => 'new'
    }
  };

  my $rewire = Rewire->new(
    services => $services
  );

This package supports specifying constructors other than the traditional new routine. A constructor is always called with the package name as the invocant.

extends

  use Rewire;

  my $services = {
    io => {
      package => 'IO/Handle'
    },
    log => {
      package => 'Mojo/Log',
      argument => {
        handle => { '$service' => 'io' }
      }
    },
    development_log => {
      package => 'Mojo/Log',
      extends => 'log',
      builder => [
        {
          method => 'new',
          return => 'self'
        },
        {
          method => 'path',
          argument => '/tmp/development.log',
          return => 'none'
        },
        {
          method => 'level',
          argument => 'debug',
          return => 'none'
        }
      ]
    },
    production_log => {
      package => 'Mojo/Log',
      extends => 'log',
      builder => [
        {
          method => 'new',
          return => 'self'
        },
        {
          method => 'path',
          argument => '/tmp/production.log',
          return => 'none'
        },
        {
          method => 'level',
          argument => 'warn',
          return => 'none'
        }
      ]
    },
    staging_log => {
      package => 'Mojo/Log',
      extends => 'development_log',
    },
    testing_log => {
      package => 'Mojo/Log',
      extends => 'log',
    },
  };

  my $rewire = Rewire->new(
    services => $services
  );

This package supports extending services in the definition of other services, recursively compiling service configurations and eventually executing the requested compiled service.

function

  use Rewire;

  my $services = {
    foo_sum => {
      package => 'Mojo/Util',
      function => 'md5_sum',
      argument => 'foo',
    }
  };

  my $rewire = Rewire->new(
    services => $services,
  );

This package supports specifying construction as a function call, which when called does not provide an invocant.

lifecycle

  use Rewire;

  my $metadata = {
    home => '/home/ubuntu'
  };

  my $services = {
    tempfile => {
      package => 'Mojo/File',
      argument => { '$metadata' => 'home' },
      lifecycle => 'singleton'
    }
  };

  my $rewire = Rewire->new(
    services => $services,
    metadata => $metadata
  );

This package supports different lifecycle options which determine when services are built and whether they're persisted.

metadata

  use Rewire;

  my $metadata = {
    homedir => '/home',
    tempdir => '/tmp'
  };

  my $services = {
    home => {
      package => 'Mojo/Path',
      argument => { '$metadata' => 'homedir' },
    },
    temp => {
      package => 'Mojo/Path',
      argument => { '$metadata' => 'tempdir' },
    }
  };

  my $rewire = Rewire->new(
    services => $services,
    metadata => $metadata
  );

This package supports specifying data and structures which can be used in the construction of multiple services.

method

  use Rewire;

  my $services = {
    mojo_url => {
      package => 'Mojo/URL',
      argument => 'https://perl.org',
      method => 'new'
    }
  };

  my $rewire = Rewire->new(
    services => $services,
  );

This package supports specifying construction as a method call, which when called provides the package or object instance as the invocant.

proxyable

  use Rewire;

  my $services = {
    home => {
      package => 'Mojo/Path',
      argument => '/home',
    },
    temp => {
      package => 'Mojo/Path',
      argument => '/tmp',
    }
  };

  my $rewire = Rewire->new(
    services => $services
  );

  # resolve services via method calls
  [
    $rewire->home, # i.e. $rewire->process('home')
    $rewire->temp  # i.e. $rewire->process('temp')
  ]

This package supports the resolution of services using a single method call. This is enabled by intercepting method calls and proxying them to the "process" method.

routine

  use Rewire;

  my $services = {
    mojo_url => {
      package => 'Mojo/URL',
      argument => 'https://perl.org',
      routine => 'new'
    }
  };

  my $rewire = Rewire->new(
    services => $services,
  );

This package supports specifying construction as a function call, which when called provides the package as the invocant.

service

  my $metadata = {
    home => '/home/ubuntu'
  };

  my $services = {
    tempfile => {
      package => 'Mojo/File',
      argument => { '$metadata' => 'home' },
      lifecycle => 'eager'
    }
  };

  my $rewire = Rewire->new(
    services => $services,
    metadata => $metadata
  );

This package supports defining services to be constructed on-demand or automatically on instantiation.

ATTRIBUTES

This package has the following attributes:

context

  context(CodeRef)

This attribute is read-only, accepts (CodeRef) values, and is optional.

engine

  engine(InstanceOf["Data::Object::Space"])

This attribute is read-only, accepts (InstanceOf["Data::Object::Space"]) values, and is optional.

metadata

  metadata(HashRef)

This attribute is read-only, accepts (HashRef) values, and is optional.

services

  services(HashRef)

This attribute is read-only, accepts (HashRef) values, and is optional.

METHODS

This package implements the following methods:

config

  config() : HashRef

The config method returns the configuration based on the services and metadata attributes.

config example #1
  # given: synopsis

  $rewire->config;

process

  process(Str $name, Any $argument, Maybe[Str] $argument_as) : Any

The process method processes and returns an object or value based on the service named but where the arguments are provided ad-hoc. Note: This method is meant to be used to construct services ad-hoc and as such bypasses caching and lifecycle effects.

process example #1
  # given: synopsis

  $rewire->process('tempfile', 'rewire.tmp');
process example #2
  use Rewire;

  my $metadata = {
    logfile => '/var/log/rewire.log',
  };

  my $services = {
    mojo_log => {
      package => 'Mojo/Log',
      argument => { '$metadata' => 'logfile' },
    }
  };

  my $rewire = Rewire->new(
    services => $services,
    metadata => $metadata
  );

  $rewire->process('mojo_log', {
    level => 'fatal',
    path => { '$metadata' => 'logfile' }
  });
process example #3
  use Rewire;

  my $metadata = {
    logfile => '/var/log/rewire.log',
  };

  my $services = {
    mojo_log => {
      package => 'Mojo/Log',
      builder => [
        {
          method => 'new',
          return => 'self'
        }
      ]
    }
  };

  my $rewire = Rewire->new(
    services => $services,
    metadata => $metadata
  );

  $rewire->process('mojo_log', {
    level => 'fatal',
    path => { '$metadata' => 'logfile' }
  });

resolve

  resolve(Str $name) : Any

The resolve method resolves and returns an object or value based on the service named. Note: This method is recommended to be used to construct services as defined by the configuration and as such doesn't not allow passing additional arguments.

resolve example #1
  # given: synopsis

  $rewire->resolve('tempfile');
resolve example #2
  use Rewire;

  my $services = {
    mojo_log => {
      package => 'Mojo/Log',
      argument => {
        level => 'fatal',
        path => '/var/log/rewire.log'
      },
    }
  };

  my $rewire = Rewire->new(
    services => $services,
  );

  $rewire->resolve('mojo_log');
resolve example #3
  package Dynamic;

  sub import;

  sub AUTOLOAD {
    bless {};
  }

  sub DESTROY {
    ; # noop
  }

  package main;

  use Rewire;

  my $services = {
    dynamic => {
      package => 'Dynamic',
      builder => [
        {
          method => 'new',
          return => 'self'
        },
        {
          method => 'missing_method',
          return => 'result'
        }
      ],
    }
  };

  my $rewire = Rewire->new(
    services => $services,
  );

  $rewire->resolve('dynamic');

validate

  validate() : Object

The validate method validates the configuration and throws an exception if invalid, otherwise returns itself.

validate example #1
  # given: synopsis

  $rewire->validate;

AUTHOR

Al Newkirk, awncorp@cpan.org

LICENSE

Copyright (C) 2011-2019, Al Newkirk, et al.

This is free software; you can redistribute it and/or modify it under the terms of the The Apache License, Version 2.0, as elucidated in the "license file".

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