Add mechanism for running migrations of developer workspaces

.gitignore

@@ -38,3 +38,5 @@ ghostdriver.log
 node_modules
 .pip_download_cache/
 .prereqs_cache
+autodeploy.properties
+.ws_migrations_complete

rakefiles/prereqs.rake

@@ -11,21 +11,21 @@ desc "Install all prerequisites needed for the lms and cms"
 task :install_prereqs => [:install_node_prereqs, :install_ruby_prereqs, :install_python_prereqs]
 
 desc "Install all node prerequisites for the lms and cms"
-task :install_node_prereqs do
+task :install_node_prereqs => "ws:migrate" do
     when_changed('package.json') do
         sh('npm install')
     end unless ENV['NO_PREREQ_INSTALL']
 end
 
 desc "Install all ruby prerequisites for the lms and cms"
-task :install_ruby_prereqs do
+task :install_ruby_prereqs => "ws:migrate" do
     when_changed('Gemfile') do
         sh('bundle install')
     end unless ENV['NO_PREREQ_INSTALL']
 end
 
 desc "Install all python prerequisites for the lms and cms"
-task :install_python_prereqs do
+task :install_python_prereqs => "ws:migrate" do
     when_changed('requirements/**') do
         ENV['PIP_DOWNLOAD_CACHE'] ||= '.pip_download_cache'
         sh('pip install --exists-action w -r requirements/base.txt')

rakefiles/workspace.rake

+MIGRATION_MARKER_DIR = File.join(REPO_ROOT, '.ws_migrations_complete')
+SKIP_MIGRATIONS = ENV['SKIP_WS_MIGRATIONS'] || false
+
+directory MIGRATION_MARKER_DIR
+
+namespace :ws do
+    task :migrate => MIGRATION_MARKER_DIR do
+        Dir['ws_migrations/*'].select{|m| File.executable?(m)}.each do |migration|
+            completion_file = File.join(MIGRATION_MARKER_DIR, File.basename(migration))
+            if ! File.exist?(completion_file)
+                sh(migration)
+                File.write(completion_file, "")
+            end
+        end unless SKIP_MIGRATIONS
+    end
+end
\ No newline at end of file

ws_migrations/README.rst

+Developer Workspace Migrations
+==============================
+
+This directory contains executable files which run once prior to
+installation of pre-requisites to bring a developers workspace
+into line.
+
+Specifications
+--------------
+
+Each file in this directory should meet the following criteria
+
+* Executable (`chmod +x ws_migrations/foo.sh`)
+* Idempotent (ideally, each script is run only once, but no
+  guarantees are made by the caller, so the script must do
+  the right thing)
+* Either fast or verbose (if the script is going to take
+  a long time, it should notify the user of that)
+* A comment at the top of the file explaining the migration
+
+Execution
+---------
+
+The scripts are run by the rake task `ws:migrate`. That task
+only runs a given script if a corresponding marker file
+in .completed-ws-migrations doesn't already exist.
+
+If the SKIP_WS_MIGRATIONS environment variable is set, then
+no workspace migrations will be run.
\ No newline at end of file

ws_migrations/clean_xmodule_assets.sh

+#! /bin/sh
+
+# Remove all of the old xmodule coffee and sass directories
+# in preparation to switching to use the xmodule_assets script
+
+rm -rf cms/static/coffee/descriptor
+rm -rf cms/static/coffee/module
+rm -rf cms/static/sass/descriptor
+rm -rf cms/static/sass/module
+rm -rf lms/static/coffee/module
+rm -rf lms/static/sass/module