Chris Roberts 5d70cc3bf2 Retain original trigger behavior
These updates allow the after trigger to behave the same as the
original with regards to the execution location of the trigger
within the execution stack.
2020-04-03 15:47:00 -07:00

296 lines
11 KiB
Ruby

module Vagrant
module Action
# 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)
#
class Builder
# This is the stack of middlewares added. This should NOT be used
# directly.
#
# @return [Array]
attr_reader :stack
# 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.
#
# @return [Builder]
def self.build(middleware, *args, &block)
new.use(middleware, *args, &block)
end
def initialize
@stack = []
end
# Implement a custom copy that copies the stack variable over so that
# we don't clobber that.
def initialize_copy(original)
super
@stack = original.stack.dup
end
# 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.
def flatten
lambda do |env|
self.call(env)
end
end
# 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.
#
# @param [Class] middleware The middleware class
def use(middleware, *args, &block)
if middleware.kind_of?(Builder)
# Merge in the other builder's stack into our own
self.stack.concat(middleware.stack)
else
self.stack << [middleware, args, block]
end
self
end
# Inserts a middleware at the given index or directly before the
# given middleware object.
def insert(index, middleware, *args, &block)
index = self.index(index) unless index.is_a?(Integer)
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, [middleware, args, block])
end
end
alias_method :insert_before, :insert
# Inserts a middleware after the given index or middleware object.
def insert_after(index, middleware, *args, &block)
index = self.index(index) unless index.is_a?(Integer)
raise "no such middleware to insert after: #{index.inspect}" unless index
insert(index + 1, middleware, *args, &block)
end
# Replaces the given middlware object or index with the new
# middleware.
def replace(index, middleware, *args, &block)
if index.is_a?(Integer)
delete(index)
insert(index, middleware, *args, &block)
else
insert_before(index, middleware, *args, &block)
delete(index)
end
end
# Deletes the given middleware object or index
def delete(index)
index = self.index(index) unless index.is_a?(Integer)
stack.delete_at(index)
end
# Runs the builder stack with the given environment.
def call(env)
to_app(env).call(env)
end
# Returns the numeric index for the given middleware object.
#
# @param [Object] object The item to find the index for
# @return [Integer]
def index(object)
stack.each_with_index do |item, i|
return i if item == object
return i if item[0] == object
return i if item[0].respond_to?(:name) && item[0].name == object
end
nil
end
# Converts the builder stack to a runnable action sequence.
#
# @param [Hash] env The action environment hash
# @return [Warden] A callable object
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
# Find any action hooks or triggers which have been defined
# for items within the stack. Update the stack with any
# hooks or triggers found.
#
# @param [Hash] env Call environment
# @return [Builder] self
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
# 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)
#
# @param [Hash] env Call environment
# @return [Builder]
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).empty?
hook.prepend(Vagrant::Action::Builtin::Trigger,
env[:raw_action_name], env[:triggers], :before, :action)
end
if !env[:triggers].find(env[:raw_action_name], :after, machine_name, :action).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)
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
end
end
end