Class: DiscourseSD

Inherits:
Object
  • Object
show all
Defined in:
lib/discourse_sd.rb,
lib/discourse_sd/version.rb

Constant Summary collapse

VERSION = 
'0.0.7'

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(zone) ⇒ DiscourseSD

Create an instance of DiscourseSD to lookup services in the given zone.

Parameters:

  • zone (String) —

    The zone in which all services should be found.



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# File 'lib/discourse_sd.rb', line 25

def initialize(zone)
  @zone = zone
end

Instance Attribute Details

#zone ⇒ Object (readonly)

Returns the value of attribute zone.



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# File 'lib/discourse_sd.rb', line 7

def zone
  @zone
end

Class Method Details

.create_from_env ⇒ DiscourseSD

Create an instance of DiscourseSD to lookup services in the zone determined from the environment.

Returns:



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# File 'lib/discourse_sd.rb', line 13

def self.create_from_env
  if sd_dns = Resolv::DNS.new.getresources("powerdns._domain._tcp", Resolv::DNS::Resource::IN::SRV).first
    parts = sd_dns.target.to_s.split('.')
    new(parts[parts.rindex('sd')..-1].join('.'))
  else
    raise RuntimeError, "No PowerDNS servers were found!"
  end
end

Instance Method Details

#service_instances(prefix) ⇒ Hash

Looks up all the services relevant to a Discourse app, and returns a hash with their IPv6 addresses and ports using the same key names that are used in the Discourse config.

Parameters:

  • prefix (String) —

    The name of the Discourse app cluster.

Returns:

  • (Hash) —

    IP addresses and ports for services.



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# File 'lib/discourse_sd.rb', line 36

def service_instances(prefix)
  config = {}
  sd = DNSSD.new(@zone)

  redises = redis_service_instances(sd, prefix)
  pgbouncers = pgbouncer_service_instances(sd, prefix)

  Resolv::DNS.open do |dns|
    redis_master = redises.first
    redis_slave = redises.size > 1 ? redises.last : nil

    if redis_master
      config[:redis_host] = aaaa_record(dns, redis_master.hostname).to_s
      config[:redis_port] = redis_master.port
    end
    if redis_slave
      config[:redis_slave_host] = aaaa_record(dns, redis_slave.hostname).to_s
      config[:redis_slave_port] = redis_slave.port
    end

    db_master = pgbouncers.first
    db_replica = pgbouncers.size > 1 ? pgbouncers.last : nil

    if db_master
      config[:db_host] = aaaa_record(dns, db_master.hostname).to_s
      config[:db_port] = db_master.port
    end
    if db_replica
      config[:db_replica_host] = aaaa_record(dns, db_replica.hostname).to_s
      config[:db_replica_port] = db_replica.port
    end
  end

  config
end