1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
|
#
# Author:: Lamont Granquist (<lamont@chef.io>)
# Copyright:: Copyright (c) 2015 Chef Software, Inc.
# License:: Apache License, Version 2.0
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
require 'chef/exceptions'
require 'chef/platform/resource_priority_map'
require 'chef/mixin/convert_to_class_name'
class Chef
class ResourceResolver
include Chef::Mixin::ConvertToClassName
attr_reader :node
attr_reader :resource
attr_reader :action
def initialize(node, resource)
@node = node
@resource = resource.to_sym
end
# return a deterministically sorted list of Chef::Resource subclasses
def resources
@resources ||= Chef::Resource.descendants
end
def resolve
maybe_dynamic_resource_resolution ||
maybe_chef_platform_lookup
end
# this cut looks at if the resource can handle the resource type on the node
def enabled_handlers
@enabled_handlers ||=
resources.select do |klass|
klass.provides?(node, resource)
end.sort {|a,b| a.to_s <=> b.to_s }
end
#
# Resolve a resource by name.
#
# @param resource_name [Symbol] The resource DSL name (e.g. `:file`)
# @param node [Chef::Node] The node on which the resource will run.
#
def self.resolve(resource_name, node: Chef.node)
new(node, resource_name).resolve
end
private
# try dynamically finding a resource based on querying the resources to see what they support
def maybe_dynamic_resource_resolution # log this so we know what resources will work for the generic resource on the node (early cut)
Chef::Log.debug "resources for generic #{resource} resource enabled on node include: #{enabled_handlers}"
# if none of the resources specifically support the resource, we still need to pick one of the resources that are
# enabled on the node to handle the why-run use case.
handlers = enabled_handlers
if handlers.size >= 2
# this magic stack ranks the resources by where they appear in the resource_priority_map
priority_list = [ get_priority_array(node, resource) ].flatten.compact
handlers = handlers.sort_by { |x| i = priority_list.index x; i.nil? ? Float::INFINITY : i }
if priority_list.index(handlers.first).nil?
# if we had more than one and we picked one with a precidence of infinity that means that the resource_priority_map
# entry for this resource is missing -- we should probably raise here and force resolution of the ambiguity.
Chef::Log.warn "Ambiguous resource precedence: #{handlers}, please use Chef.set_resource_priority_array to provide determinism"
end
handlers = handlers[0..0]
end
Chef::Log.debug "resources that survived replacement include: #{handlers}"
raise Chef::Exceptions::AmbiguousResourceResolution.new(resource, handlers) if handlers.count >= 2
Chef::Log.debug "dynamic resource resolver FAILED to resolve a resource" if handlers.empty?
return nil if handlers.empty?
handlers[0]
end
# try the old static lookup of resources by mangling name to resource klass
def maybe_chef_platform_lookup
Chef::Resource.resource_matching_short_name(resource)
end
# dep injection hooks
def get_priority_array(node, resource_name)
resource_priority_map.get_priority_array(node, resource_name)
end
def resource_priority_map
Chef::Platform::ResourcePriorityMap.instance
end
end
end
|
