Reconfigure buckets around after each provisioner

Unfortunately I couldn't think of another way of doing this apart from
monkey patching, there is no way to replace a previously defined action
neither we can hook into calls to provisioners themselves.

lib/vagrant-cachier/action/install.rb

@@ -1,54 +0,0 @@
-module VagrantPlugins
-  module Cachier
-    class Action
-      class Install
-        def initialize(app, env)
-          @app    = app
-          @logger = Log4r::Logger.new("vagrant::cachier::action::install")
-        end
-
-        def call(env)
-          return @app.call(env) unless env[:machine].config.cache.enabled?
-
-          @env = env
-
-          FileUtils.mkdir_p(cache_root.to_s) unless cache_root.exist?
-
-          nfs_flag = env[:machine].config.cache.enable_nfs
-          env[:machine].config.vm.synced_folder cache_root, '/tmp/vagrant-cache', id: "vagrant-cache", nfs: nfs_flag
-
-          @app.call env
-
-          env[:cache_dirs] = []
-
-          if env[:machine].config.cache.auto_detect
-            Bucket.auto_detect(env)
-          end
-
-          if env[:machine].config.cache.buckets.any?
-            env[:ui].info 'Configuring cache buckets...'
-            cache_config = env[:machine].config.cache
-            cache_config.buckets.each do |bucket_name, configs|
-              @logger.debug "Installing #{bucket_name} with configs #{configs.inspect}"
-              Bucket.install(bucket_name, env, configs)
-            end
-
-            data_file = env[:machine].data_dir.join('cache_dirs')
-            data_file.open('w') { |f| f.print env[:cache_dirs].join("\n") }
-          end
-        end
-
-        def cache_root
-          @cache_root ||= case @env[:machine].config.cache.scope
-            when :box
-              @env[:home_path].join('cache', @env[:machine].box.name)
-            when :machine
-              @env[:machine].data_dir.join('cache')
-            else
-              raise "Unknown cache scope: '#{@env[:machine].config.cache.scope}'"
-          end
-        end
-      end
-    end
-  end
-end

lib/vagrant-cachier/action/provision_ext.rb

@@ -0,0 +1,70 @@
+require_relative '../bucket'
+
+module VagrantPlugins
+  module Cachier
+    module Action
+      module ProvisionExt
+        def self.included(base)
+          base.class_eval do
+            def cachier_debug(msg)
+              @logger.debug "[CACHIER] #{msg}"
+            end
+
+            alias :old_call :call
+            def call(env)
+              return old_call(env) unless env[:machine].config.cache.enabled?
+
+              @env = env
+
+              FileUtils.mkdir_p(cache_root.to_s) unless cache_root.exist?
+
+              nfs_flag = env[:machine].config.cache.enable_nfs
+              env[:machine].config.vm.synced_folder cache_root, '/tmp/vagrant-cache', id: "vagrant-cache", nfs: nfs_flag
+
+              env[:cache_dirs] = []
+
+              old_call(env)
+
+              configure_cache_buckets
+            end
+
+            alias :old_run_provisioner :run_provisioner
+            def run_provisioner(*args)
+              configure_cache_buckets
+              old_run_provisioner(*args)
+            end
+
+            def configure_cache_buckets
+              if @env[:machine].config.cache.auto_detect
+                Bucket.auto_detect(@env)
+              end
+
+              return unless @env[:machine].config.cache.buckets.any?
+
+              @env[:ui].info 'Configuring cache buckets...'
+              cache_config = @env[:machine].config.cache
+              cache_config.buckets.each do |bucket_name, configs|
+                cachier_debug "Installing #{bucket_name} with configs #{configs.inspect}"
+                Bucket.install(bucket_name, @env, configs)
+              end
+
+              data_file = @env[:machine].data_dir.join('cache_dirs')
+              data_file.open('w') { |f| f.print @env[:cache_dirs].uniq.join("\n") }
+            end
+
+            def cache_root
+              @cache_root ||= case @env[:machine].config.cache.scope
+                when :box
+                  @env[:home_path].join('cache', @env[:machine].box.name)
+                when :machine
+                  @env[:machine].data_dir.join('cache')
+                else
+                  raise "Unknown cache scope: '#{@env[:machine].config.cache.scope}'"
+              end
+            end
+          end
+        end
+      end
+    end
+  end
+end

lib/vagrant-cachier/plugin.rb

@@ -1,3 +1,8 @@
+require_relative 'action/provision_ext'
+Vagrant::Action::Builtin::Provision.class_eval do
+  include VagrantPlugins::Cachier::Action::ProvisionExt
+end
+
 module VagrantPlugins
   module Cachier
     class Plugin < Vagrant.plugin('2')
@@ -38,13 +43,6 @@ module VagrantPlugins
         Cap::Arch::PacmanCacheDir
       end
 
-      install_action_hook = lambda do |hook|
-        require_relative 'action/install'
-        hook.after Vagrant::Action::Builtin::Provision, VagrantPlugins::Cachier::Action::Install
-      end
-      action_hook 'set-shared-cache-on-machine-up',     :machine_action_up, &install_action_hook
-      action_hook 'set-shared-cache-on-machine-reload', :machine_action_reload, &install_action_hook
-
       clean_action_hook = lambda do |hook|
         require_relative 'action/clean'
         hook.before Vagrant::Action::Builtin::GracefulHalt, VagrantPlugins::Cachier::Action::Clean