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
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
|
#
# Author:: Richard Manyanza (<liseki@nyikacraftsmen.com>)
# Copyright:: Copyright (c) 2014 Richard Manyanza.
# 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/priority_map'
class Chef
#
# Provider Resolution
# ===================
#
# Provider resolution is the process of taking a Resource object and an
# action, and determining the Provider class that should be instantiated to
# handle the action.
#
# If the resource has its `provider` set, that is used.
#
# Otherwise, we take the lists of Providers that have registered as
# providing the DSL through `provides :dsl_name, <filters>` or
# `Chef.set_resource_priority_array :dsl_name, <filters>`. We filter each
# list of Providers through:
#
# 1. The filters it was registered with (such as `os: 'linux'` or
# `platform_family: 'debian'`)
# 2. `provides?(node, resource)`
# 3. `supports?(resource, action)`
#
# Anything that passes the filter and returns `true` to provides and supports,
# is considered a match. The first matching Provider in the *most recently
# registered list* is selected and returned.
#
class ProviderResolver
attr_reader :node
attr_reader :resource
attr_reader :action
def initialize(node, resource, action)
@node = node
@resource = resource
@action = action
end
def resolve
maybe_explicit_provider(resource) ||
maybe_dynamic_provider_resolution(resource, action) ||
maybe_chef_platform_lookup(resource)
end
def provided_by?(provider_class)
potential_handlers.include?(provider_class)
end
private
# if resource.provider is set, just return one of those objects
def maybe_explicit_provider(resource)
return nil unless resource.provider
resource.provider
end
# try dynamically finding a provider based on querying the providers to see what they support
def maybe_dynamic_provider_resolution(resource, action)
Chef::Log.debug "Providers for generic #{resource.resource_name} resource enabled on node include: #{enabled_handlers}"
if supported_handlers.empty?
# if none of the providers specifically support the resource, we still need to pick one of the providers that are
# enabled on the node to handle the why-run use case. FIXME we should only do this in why-run mode then.
Chef::Log.debug "No providers responded true to `supports?` for action #{action} on resource #{resource}, falling back to enabled handlers so we can return something anyway."
handler = enabled_handlers.first
else
handler = supported_handlers.first
end
if handler
Chef::Log.debug "Provider for action #{action} on resource #{resource} is #{handler}"
else
Chef::Log.debug "Dynamic provider resolver FAILED to resolve a provider for action #{action} on resource #{resource}"
end
handler
end
# try the old static lookup of providers by platform
def maybe_chef_platform_lookup(resource)
Chef::Platform.find_provider_for_node(node, resource)
end
def priority_map
Chef::Platform::ProviderPriorityMap.instance
end
# @api private
def potential_handlers
priority_map.list_handlers(node, resource.resource_name).flatten(1).uniq
end
def enabled_handlers
@enabled_handlers ||= potential_handlers.select { |handler| handler.method(:provides?).owner == Chef::Provider || handler.provides?(node, resource) }
end
# TODO deprecate this and allow actions to be passed as a filter to
# `provides` so we don't have to have two separate things.
# @api private
def supported_handlers
@supported_handlers ||=
enabled_handlers.select { |handler| handler.supports?(resource, action) }
end
module Deprecated
# return a deterministically sorted list of Chef::Provider subclasses
def providers
@providers ||= Chef::Provider.descendants
end
def enabled_handlers
@enabled_handlers ||= begin
handlers = potential_handlers
# If there are no potential handlers for this node (nobody called provides)
# then we search through all classes and call provides in case someone
# defined a provides? method that returned true in spite of provides
# not being called
if handlers.empty?
warn = true
handlers = providers
end
handlers.select do |handler|
if handler.method(:provides?).owner == Chef::Provider
true
elsif handler.provides?(node, resource)
if warn
Chef::Log.deprecation("#{handler}.provides? returned true when asked if it provides DSL #{resource.resource_name}, but provides #{resource.resource_name.to_sym.inspect} was never called!")
Chef::Log.deprecation("In Chef 13, this will break: you must call provides to mark the names you provide, even if you also override provides? yourself.")
end
true
end
end
end
end
end
prepend Deprecated
end
end
|
