The Perl Toolchain Summit needs more sponsors. If your company depends on Perl, please support this very important event.
 / 
Consul-0.008
River stage one • 3 direct dependents • 3 total dependents
2 ++
/ Consul

NAME

Consul - Client library for consul

SYNOPSIS

    use Consul;
    
    my $consul = Consul->new;
    say $consul->status->leader;
    
    # shortcut to single API
    my $status = Consul->status;
    say $status->leader;

DESCRIPTION

This is a client library for accessing and manipulating data in a Consul cluster. It targets the Consul v1 HTTP API.

This module is quite low-level. You're expected to have a good understanding of Consul and its API to understand the methods this module provides. See "SEE ALSO" for further reading.

WARNING

This is still under development. The documentation isn't all there yet (in particular about the return types) and a couple of APIs aren't implemented. It's still very useful and I don't expect huge changes, but please take care when upgrading. Open an issue if there's something you need that isn't here and I'll get right on it!

CONSTRUCTOR

new

    my $consul = Consul->new( %args );

This constructor returns a new Consul client object. Valid arguments include:

  • host

    Hostname or IP address of an Consul server (default: 127.0.0.1)

  • port

    Port where the Consul server is listening (default: 8500)

  • ssl

    Use SSL/TLS (ie HTTPS) when talking to the Consul server (default: off)

  • timeout

    Request timeout. If a request to Consul takes longer that this, the endpoint method will fail (default: 15).

  • req_cb

    A callback to an alternative method to make the actual HTTP request. The callback is of the form:

        sub {
        my ($self, $method, $url, $content, $cb) = @_;
        ... do HTTP call
        $cb->($rstatus, $rreason, $rcontent);
    }

    In other words, make a request to $url using HTTP method $method, with $content in the request body, adding in the headers from $headers. Call $cb with the returned status, reason, headers and body content.

    $headers is a Hash::MultiValue. The returned headers must also be one.

    Consul itself provides a default req_cb that uses HTTP::Tiny to make calls to the server. If you provide one, you should honour the value of the timeout argument.

    req_cb can be used in conjunction with the cb option to all API method endpoints to get asynchronous behaviour. It's recommended however that you don't use this directly, but rather use a module like AnyEvent::Consul to take care of that for you.

    If you just want to use this module to make simple calls to your Consul cluster, you can ignore this option entirely.

ENDPOINTS

Individual API endpoints are implemented in separate modules. The following methods will return a context objects for the named API. Alternatively, you can request an API context directly from the Consul package. In that case, Consul->new is called implicitly.

    # these are equivalent
    my $agent = Consul->new( %args )->agent;
    my $agent = Consul->agent( %args );

kv

Key/value store API. See Consul::API::KV.

agent

Agent API. See Consul::API::Agent.

catalog

Catalog (nodes and services) API. See Consul::API::Catalog.

health

Health check API. See Consul::API::Health.

session

Sessions API. See Consul::API::Session.

acl

Access control API. See Consul::API::ACL.

event

User event API. See Consul::API::Event.

status

System status API. See Consul::API::Status.

METHOD OPTIONS

All API methods implemented by the endpoints can take a number of arguments. Most of those are documented in the endpoint documentation. There are however some that are common to all methods:

  • cb

    A callback to call with the results of the method. Without this, the results are returned from the method, but only if req_cb is synchronous. If an asynchronous req_cb is used without a cb being passed to the method, the method return value is undefined.

    If you just want to use this module to make simple calls to your Consul cluster, you can ignore this option entirely.

BLOCKING QUERIES

Some Consul API endpoints support a feature called a "blocking query". These endpoints allow long-polling for changes, and support some extra information about the server state, including the Raft index, in the response headers.

The corresponding endpoint methods, when called in array context, will return a second value. This is an object with three methods, index, last_contact and known_leader, corresponding to the similarly-named header fields. You can use these to set up state watches, CAS writes, and so on.

See the Consul API docs for more information.

SEE ALSO

SUPPORT

Bugs / Feature Requests

Please report any bugs or feature requests through the issue tracker at https://github.com/robn/p5-consul/issues. You will be notified automatically of any progress on your issue.

Source Code

This is open source software. The code repository is available for public review and contribution under the terms of the license.

https://github.com/robn/p5-consul

  git clone https://github.com/robn/p5-consul.git

AUTHORS

  • Robert Norris <rob@eatenbyagrue.org>

COPYRIGHT AND LICENSE

This software is copyright (c) 2015 by Robert Norris.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.