Class: Vagrant::Action::Builder

Inherits:
Object
  • Object
show all
Defined in:
lib/vagrant/action/builder.rb

Overview

Action builder which provides a nice DSL for building up a middleware sequence for Vagrant actions. This code is based heavily off of Rack::Builder and ActionDispatch::MiddlewareStack in Rack and Rails, respectively.

Usage

Building an action sequence is very easy:

app = Vagrant::Action::Builder.new.tap do |b|
  b.use MiddlewareA
  b.use MiddlewareB
end

Vagrant::Action.run(app)

Defined Under Namespace

Classes: MiddlewareArguments, StackItem

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Builder

Returns a new instance of Builder.



40
41
42
 
# File 'lib/vagrant/action/builder.rb', line 40

def initialize
  @stack = []
end

Instance Attribute Details

#stack ⇒ Array (readonly)

This is the stack of middlewares added. This should NOT be used directly.

Returns:

  • (Array) 


29
30
31
 
# File 'lib/vagrant/action/builder.rb', line 29

def stack
  @stack
end

Class Method Details

.build(middleware, *args, **keywords, &block) ⇒ Builder

This is a shortcut for a middleware sequence with only one item in it. For a description of the arguments and the documentation, please see #use instead.

Returns:



36
37
38
 
# File 'lib/vagrant/action/builder.rb', line 36

def self.build(middleware, *args, **keywords, &block)
  new.use(middleware, *args, **keywords, &block)
end

Instance Method Details

#apply_action_name(env) ⇒ Builder

If action hooks have not already been set, this method will perform three tasks:

  1. Load any hook triggers defined for the action_name
  2. Load any action_hooks defined from plugins
  3. Load any action triggers based on machine action called (not action classes)

Parameters:

  • env (Hash) —

    Call environment

Returns:



260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
 
# File 'lib/vagrant/action/builder.rb', line 260

def apply_action_name(env)
  return self if !env[:action_name]
  hook = Hook.new
  machine_name = env[:machine].name if env[:machine]

  # Start with loading any hook triggers if applicable
  if Vagrant::Util::Experimental.feature_enabled?("typed_triggers") && env[:triggers]
    if !env[:triggers].find(env[:action_name], :before, machine_name, :hook).empty?
      hook.prepend(Vagrant::Action::Builtin::Trigger,
        env[:action_name], env[:triggers], :before, :hook)
    end
    if !env[:triggers].find(env[:action_name], :after, machine_name, :hook).empty?
      hook.append(Vagrant::Action::Builtin::Trigger,
        env[:action_name], env[:triggers], :after, :hook)
    end
  end

  # Next we load up all the action hooks that plugins may
  # have defined
  action_hooks = Vagrant.plugin("2").manager.action_hooks(env[:action_name])
  action_hooks.each do |hook_proc|
    hook_proc.call(hook)
  end

  # Finally load any action triggers defined. The action triggers
  # are the originally implemented trigger style. They run before
  # and after specific provider actions (like :up, :halt, etc) and
  # are different from true action triggers
  if env[:triggers]
    if !env[:triggers].find(env[:raw_action_name], :before, machine_name, :action, all: true).empty?
      hook.prepend(Vagrant::Action::Builtin::Trigger,
        env[:raw_action_name], env[:triggers], :before, :action, all: true)
    end
    if !env[:triggers].find(env[:raw_action_name], :after, machine_name, :action, all: true).empty?
      # NOTE: These after triggers need to be delayed before running to
      #       allow the rest of the call stack to complete before being
      #       run. The delayed action is prepended to the stack (not appended)
      #       to ensure it is called first, which results in it properly
      #       waiting for everything to finish before itself completing.
      builder = self.class.build(Vagrant::Action::Builtin::Trigger,
        env[:raw_action_name], env[:triggers], :after, :action, all: true)
      hook.prepend(Vagrant::Action::Builtin::Delayed, builder)
    end
  end

  # If the hooks are empty, then there was nothing to apply and
  # we can just send ourself back
  return self if hook.empty?

  # These are the options to pass into hook application.
  options = {}

  # If we already ran through once and did append/prepends,
  # then don't do it again.
  if env[:action_hooks_already_ran]
    options[:no_prepend_or_append] = true
  end

  # Specify that we already ran, so in the future we don't repeat
  # the prepend/append hooks.
  env[:action_hooks_already_ran] = true

  # Apply all the hooks to the new builder instance
  hook.apply(self, options)

  self
end

#apply_dynamic_updates(env) ⇒ Builder

Find any action hooks or triggers which have been defined for items within the stack. Update the stack with any hooks or triggers found.

Parameters:

  • env (Hash) —

    Call environment

Returns:



198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
 
# File 'lib/vagrant/action/builder.rb', line 198

def apply_dynamic_updates(env)
  if Vagrant::Util::Experimental.feature_enabled?("typed_triggers")
    triggers = env[:triggers]
  end

  # Use a Hook as a convenient interface for injecting
  # any applicable trigger actions within the stack
  machine_name = env[:machine].name if env[:machine]

  # Iterate over all items in the stack and apply new items
  # into the hook as they are found. Must be sure to dup the
  # stack here since we are modifying the stack in the loop.
  stack.dup.each do |item|
    hook = Hook.new

    action = item.first
    next if action.is_a?(Proc)

    # Start with adding any action triggers that may be defined
    if triggers && !triggers.find(action, :before, machine_name, :action).empty?
      hook.prepend(Vagrant::Action::Builtin::Trigger,
        action.name, triggers, :before, :action)
    end

    if triggers && !triggers.find(action, :after, machine_name, :action).empty?
      hook.append(Vagrant::Action::Builtin::Trigger,
        action.name, triggers, :after, :action)
    end

    # Next look for any hook triggers that may be defined against
    # the dynamically generated action class hooks
    if triggers && !triggers.find(action, :before, machine_name, :hook).empty?
      hook.prepend(Vagrant::Action::Builtin::Trigger,
        action.name, triggers, :before, :hook)
    end

    if triggers && !triggers.find(action, :after, machine_name, :hook).empty?
      hook.append(Vagrant::Action::Builtin::Trigger,
        action.name, triggers, :after, :hook)
    end

    # Finally load any registered hooks for dynamically generated
    # action class based hooks
    Vagrant.plugin("2").manager.find_action_hooks(action).each do |hook_proc|
      hook_proc.call(hook)
    end

    hook.apply(self, root: item)
  end

  # Apply the hook to ourself to update the stack
  self
end

#call(env) ⇒ Object

Runs the builder stack with the given environment.



148
149
150
 
# File 'lib/vagrant/action/builder.rb', line 148

def call(env)
  to_app(env).call(env)
end

#delete(index) ⇒ Object

Deletes the given middleware object or index



142
143
144
145
 
# File 'lib/vagrant/action/builder.rb', line 142

def delete(index)
  index = self.index(index) unless index.is_a?(Integer)
  stack.delete_at(index)
end

#flatten ⇒ Object

Returns a mergeable version of the builder. If use is called with the return value of this method, then the stack will merge, instead of being treated as a separate single middleware.



55
56
57
58
59
 
# File 'lib/vagrant/action/builder.rb', line 55

def flatten
  lambda do |env|
    self.call(env)
  end
end

#index(object) ⇒ Integer

Returns the numeric index for the given middleware object.

Parameters:

  • object (Object) —

    The item to find the index for

Returns:

  • (Integer) 


156
157
158
159
160
161
162
163
164
165
 
# File 'lib/vagrant/action/builder.rb', line 156

def index(object)
  stack.each_with_index do |item, i|
    return i if item == object
    return i if item.middleware == object
    return i if item.middleware.respond_to?(:name) &&
      item.middleware.name == object
  end

  nil
end

#initialize_copy(original) ⇒ Object

Implement a custom copy that copies the stack variable over so that we don't clobber that.



46
47
48
49
50
 
# File 'lib/vagrant/action/builder.rb', line 46

def initialize_copy(original)
  super

  @stack = original.stack.dup
end

#insert(idx_or_item, middleware, *args, **keywords, &block) ⇒ Object Also known as: insert_before

Inserts a middleware at the given index or directly before the given middleware object.



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
 
# File 'lib/vagrant/action/builder.rb', line 88

def insert(idx_or_item, middleware, *args, **keywords, &block)
  item = StackItem.new(
    middleware: middleware,
    arguments: MiddlewareArguments.new(
      parameters: args,
      keywords: keywords,
      block: block
    )
  )

  if idx_or_item.is_a?(Integer)
    index = idx_or_item
  else
    index = self.index(idx_or_item)
  end

  raise "no such middleware to insert before: #{index.inspect}" unless index

  if middleware.kind_of?(Builder)
    middleware.stack.reverse.each do |stack_item|
      stack.insert(index, stack_item)
    end
  else
    stack.insert(index, item)
  end
end

#insert_after(idx_or_item, middleware, *args, **keywords, &block) ⇒ Object

Inserts a middleware after the given index or middleware object.



118
119
120
121
122
123
124
125
126
127
 
# File 'lib/vagrant/action/builder.rb', line 118

def insert_after(idx_or_item, middleware, *args, **keywords, &block)
  if idx_or_item.is_a?(Integer)
    index = idx_or_item
  else
    index = self.index(idx_or_item)
  end

  raise "no such middleware to insert after: #{index.inspect}" unless index
  insert(index + 1, middleware, *args, &block)
end

#replace(index, middleware, *args, **keywords, &block) ⇒ Object

Replaces the given middlware object or index with the new middleware.



131
132
133
134
135
136
137
138
139
 
# File 'lib/vagrant/action/builder.rb', line 131

def replace(index, middleware, *args, **keywords, &block)
  if index.is_a?(Integer)
    delete(index)
    insert(index, middleware, *args, **keywords, &block)
  else
    insert_before(index, middleware, *args, **keywords, &block)
    delete(index)
  end
end

#to_app(env) ⇒ Warden

Converts the builder stack to a runnable action sequence.

Parameters:

  • env (Hash) —

    The action environment hash

Returns:

  • (Warden) —

    A callable object



171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
 
# File 'lib/vagrant/action/builder.rb', line 171

def to_app(env)
  # Start with a duplicate of ourself which can
  # be modified
  builder = self.dup

  # Apply all dynamic modifications of the stack. This
  # will generate dynamic hooks for all actions within
  # the stack, load any triggers for action classes, and
  # apply them to the builder's stack
  builder.apply_dynamic_updates(env)

  # Now that the stack is fully expanded, apply any
  # action hooks that may be defined so they are on
  # the outermost locations of the stack
  builder.apply_action_name(env)

  # Wrap the middleware stack with the Warden to provide a consistent
  # and predictable behavior upon exceptions.
  Warden.new(builder.stack.dup, env)
end

#use(middleware, *args, **keywords, &block) ⇒ Object

Adds a middleware class to the middleware stack. Any additional args and a block, if given, are saved and passed to the initializer of the middleware.

Parameters:

  • middleware (Class) —

    The middleware class



66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
 
# File 'lib/vagrant/action/builder.rb', line 66

def use(middleware, *args, **keywords, &block)
  item = StackItem.new(
    middleware: middleware,
    arguments: MiddlewareArguments.new(
      parameters: args,
      keywords: keywords,
      block: block
    )
  )

  if middleware.kind_of?(Builder)
    # Merge in the other builder's stack into our own
    self.stack.concat(middleware.stack)
  else
    self.stack << item
  end

  self
end