// [START setting_the_current_namespace]
from google.appengine.api import namespace_manager

# Called only if the current namespace is not set.
def namespace_manager_default_namespace_for_request():
    # The returned string will be used as the Google Apps domain.
    return namespace_manager.google_apps_namespace()
// [END setting_the_current_namespace]

// [START creating_namespaces_on_a_per_user_basis]
from google.appengine.api import users

def namespace_manager_default_namespace_for_request():
    # assumes the user is logged in.
    return users.get_current_user().user_id()
// [END creating_namespaces_on_a_per_user_basis]

// [START using_namespaces_with_the_Memcache_1]
from google.appengine.api import memcache
from google.appengine.api import namespace_manager

// Set memcache using the current namespace from the namespace manager.
namespace = namespace_manager.get_namespace();
namespace_manager.set("abc");
try:
    memcache.add("key", value)
finally:
    namespace_manager.set(namespace)
// [END using_namespaces_with_the_Memcache_1]

// [START using_namespaces_with_the_Memcache_2]
// Store an entry to the memcache explicitly
memcache.add("key", data, namespace='abc')
// [END using_namespaces_with_the_Memcache_2]

// [START using_namespaces_with_the_Task_Queue]
import webapp2
from google.appengine.api import namespace_manager
from google.appengine.api import taskqueue
from google.appengine.ext import ndb

class Counter(ndb.Model):
    """Model for containing a count."""
    count = ndb.IntegerProperty()


@ndb.transactional
def update_counter(name):
   """Increment the named counter by 1 in a transaction."""
   counter = Counter.get_by_id(name)
   if counter is None:
       counter = Counter(id=name);
       counter.count = 0
   counter.count += 1
   counter.put()


class TaskQueueHandler(webapp2.RequestHandler):
    # TaskQueueHandler is mapped to '/_ah/counter'
    """Task queue handler for update_counter."""
    def post(self):
        name = self.request.get('counter_name')
        update_counter(name)


class SomeRequestViaTaskQueue(webapp2.RequestHandler):
    """Perform asynchronous requests to update counter."""
    def get(self):
        # Asynchronously updates counter.
        taskqueue.add(url='/_ah/counter',
                      params={'counter_name':
                              'SomeRequestViaTaskQueue'})
        # try/finally pattern to temporarily set the namespace.
        # Save the current namespace.
        namespace = namespace_manager.get_namespace()
        try:
            # Asynchronously updates counter.
            namespace_manager.set_namespace('-global-')
            taskqueue.add(url='/_ah/counter',
                          params={'counter_name':
                                  'SomeRequestViaTaskQueue'})
        finally:
            # Restore the saved namespace.
            namespace_manager.set_namespace(namespace)
        self.response.write('<html><body><p>')
        self.response.write('Counters will be updated')
        self.response.write('</p></body></html>')
        
app = webapp2.WSGIApplication([('/_ah/counter', TaskQueueHandler),
                               ('/some_request', SomeRequestViaTaskQueue)],
                               debug=True)
// [END using_namespaces_with_the_Task_Queue]