Class: Redis::Directory

Inherits:
Object
  • Object
show all
Defined in:
lib/redis_directory.rb

Defined Under Namespace

Classes: ReservationError, UndefinedServiceError

Constant Summary collapse

SERVICES_KEY = 
"services"
DATABASES_KEY = 
"databases"
MAXIMUM_DATABASE_COUNT =

Hard-coded, because I don’t know how to get this from the Redis connection at runtime.

65535

Instance Method Summary collapse

Constructor Details

#initialize(connection_options) ⇒ Directory

You must provide the connection_options to the directory server.



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# File 'lib/redis_directory.rb', line 28

def initialize(connection_options)
  @redis = Redis.connect(connection_options)
end

Instance Method Details

#get(service_name, connection_name) ⇒ Object

Raises:



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# File 'lib/redis_directory.rb', line 64

def get(service_name, connection_name)
  db = reserve(service_name, connection_name)
  raise ReservationError.new(self, service_name, connection_name) if db.nil?
  
  connection_list = services[service_name].map do |server|
    if server =~ /^redis\:\/\//
      "#{server}/#{db}"
    else
      "redis://#{server}/#{db}"
    end
  end
  connection = nil
  
  if connection_list.size == 1
    connection = Redis.connect(:url => connection_list.first)
  else
    connection = Redis::Distributed.new(connection_list)
  end
  
  connection.set("connection-name", connection_name)
  connection
end

#next_db(service_name) ⇒ Object

This locates the next available database for a given service, starting at an index of 1. The 0 database is reserved in case you have a default connection, or local redis server (in which case 0 should be the directory database to avoid conflicts).

Raises:



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# File 'lib/redis_directory.rb', line 45

def next_db(service_name)
  raise UndefinedServiceError.new(self, service_name) unless services.keys.include?(service_name)
  databases = redis.hvals("#{service_name}-service").map { |i| i.to_i }.sort
  (1..MAXIMUM_DATABASE_COUNT).select { |i| break i unless databases.include? i }
end

#redis ⇒ Object 



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# File 'lib/redis_directory.rb', line 87

def redis
  @redis
end

#reserve(service_name, connection_name) ⇒ Object 



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# File 'lib/redis_directory.rb', line 51

def reserve(service_name, connection_name)
  new_db = nil
  # redis.multi do
    if redis.hexists("#{service_name}-service", connection_name)
      new_db = redis.hget("#{service_name}-service", connection_name)
    else
      new_db = next_db(service_name)
      redis.hset("#{service_name}-service", connection_name, new_db)
    end
  # end
  new_db
end

#services ⇒ Object 



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# File 'lib/redis_directory.rb', line 32

def services
  if redis.exists(SERVICES_KEY)
    redis.hgetall(SERVICES_KEY).inject({}) do |h,(k,v)|
      h[k] = JSON.parse(v); h
    end
  else
    {}
  end
end