Module: Blender::Manifest::Nodes

Included in:
Root
Defined in:
lib/blender/manifest/nodes.rb

Overview

This module encapsulates nodes handeling Nodes can be declared both on a class level and inside a recipe When defining a node an ‘id’ is associated with its hostname and the node can later be reffered by this id (for example to get its ip)

Constant Summary collapse

@@internal_hostnames =

this holds the map from host ids to hostnames

{}
@@external_hostnames = 
{}

Class Method Summary collapse

Instance Method Summary collapse

Class Method Details

.included(base) ⇒ Object 



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# File 'lib/blender/manifest/nodes.rb', line 8

def self.included(base)
  base.send :extend, self
end

Instance Method Details

#addr(id) ⇒ Object

find out node addr. try to use external, then internal, then the host id to determine ip

Parameters:

  • id (Symbol, String) —

    id of the host to resolve



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# File 'lib/blender/manifest/nodes.rb', line 92

def addr(id)
  [hostname(id, true).to_s, hostname(id).to_s, id.to_s].each do |name|
    ip = host_ip(name)
    return ip if ip
  end

  # if all else fails, we should still be able to address the current node
  current_node?(id) ? "127.0.0.1" : nil
end

#addr!(id) ⇒ Object

same as addr but throws exception if IP can’t be found



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# File 'lib/blender/manifest/nodes.rb', line 103

def addr!(id)
  addr(id) or raise "Can't find address for '#{id}'"
end

#current_node ⇒ Object

returns id of the node we are running at Note: will ONLY return non-nil value after (or during) node definition

unless node is forced by environment NODE variable or /etc/node file



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# File 'lib/blender/manifest/nodes.rb', line 28

def current_node
  node = ENV['NODE'] ||
    (File.exists?("/etc/node") && File.read("/etc/node").strip) ||
    @@internal_hostnames.index(hostname) ||
    @@external_hostnames.index(hostname(nil, true))
  node && node.to_sym
end

#current_node?(id) ⇒ Boolean

Returns true if we are running on the node with the given ‘id`.

Returns:

  • (Boolean) —

    true if we are running on the node with the given ‘id`



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# File 'lib/blender/manifest/nodes.rb', line 37

def current_node?(id)
  current_node == id.to_sym
end

#host_ip(name) ⇒ Object 



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# File 'lib/blender/manifest/nodes.rb', line 45

def host_ip(name)
  return nil unless name && !name.empty?
  @host_ips ||= {}
  @host_ips[name] ||= Resolv.getaddress(name) rescue nil
end

#hostname(id = nil, external = false) ⇒ Object

returns hostname by id or local host’s name if the id is nil



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# File 'lib/blender/manifest/nodes.rb', line 17

def hostname(id = nil, external = false)
  if id
    (external ? @@external_hostnames : @@internal_hostnames)[id]
  else
    external ? Facter.fqdn : Facter.hostname
  end
end

#node(id, internal_name = nil, external_name = internal_name) ⇒ Object

define node and conditionally execute code block only on the specific node Note: can be called multiple times without internal_name and external_name parameters

in which case will only do the conditional execution

Examples:

node :app, "host5", "host5.serverfarm2.localdomain" do
  ...
end

node :app do
  ...
end

Parameters:

  • id (Symbol, String) —

    of the host to define or test for

  • internal_name (String) (defaults to: nil) —

    short hostname for the host

  • external_name (String) (defaults to: internal_name) —

    full dns hostname for the host



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# File 'lib/blender/manifest/nodes.rb', line 76

def node(id, internal_name = nil, external_name = internal_name)
  return if false == internal_name # can be used to temporary 'disable' host's definition
  # like:
  # host :app2, false do .. end
  @@internal_hostnames[id] = (internal_name || id).to_s
  @@external_hostnames[id] = external_name.to_s if external_name

  if block_given? && current_node?(id)
    puts "NODE: #{id} / #{current_node}"
    @node = id
    yield
  end
end

#resolv ⇒ Object

resolves host name using ‘host’ executable Note: cached value from @host_ips will be used if exists

Returns:

  • host’s IP by its name or nil if not found



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# File 'lib/blender/manifest/nodes.rb', line 44

require 'resolv'

#set_host_ip(name, ip) ⇒ Object

sets cache value for host ip allows resolving hosts that can’t be resolved through the sytem

Parameters:

  • name (String) —

    host name

  • ip (String) —

    host ip

Returns:

  • ip



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# File 'lib/blender/manifest/nodes.rb', line 56

def set_host_ip(name, ip)
  @host_ips ||= {}
  @host_ips[name] = ip
end