google.appengine.api.capabilities package

Summary

Allows applications to identify API outages and scheduled downtime.

This API is not recommended. The API checks the availability of App Engine bundled services, but these services are all highly available with no scheduled downtime.

Every is_enabled request to this API always returns true except for "Datastore write", which returns false if Datastore is in read-only mode for your app.

Example:

def StoreUploadedProfileImage(self):
  uploaded_image = self.request.get('img')
  # If the images API is unavailable, we'll just skip the resize.
  if CapabilitySet('images').is_enabled():
    uploaded_image = images.resize(uploaded_image, 64, 64)
  store(uploaded_image)

def RenderHTMLForm(self):
  datastore_readonly = CapabilitySet('datastore_v3', capabilities=['write'])
  if datastore_readonly.is_enabled():
    # ...render form normally...
  else:
    # self.response.out('<p>Not accepting submissions right now: %s</p>' %
                        datastore_readonly.admin_message())
    # ...render form with form elements disabled...

Individual API wrapper modules should expose CapabilitySet objects for users rather than relying on users to create them. They can also create convenience methods that delegate to the relevant CapabilitySet; for example, db.IsReadOnly().

Contents

class google.appengine.api.capabilities.CapabilitySet(package, capabilities=None, methods=None, stub_map=google.appengine.api.apiproxy_stub_map)source

Bases: object

Encapsulates one or more capabilities.

Capabilities can either be named explicitly, or inferred from the list of methods provided. If no capabilities or methods are provided, this will check whether the entire package is enabled.

admin_message()source

Retrieves any administrator notice messages for these capabilities.

Returns

A string containing one or more administrator messages, or an empty string.

Raises

UnknownCapabilityError – If a specified capability was not recognized.

is_enabled()source

Tests whether the capabilities are currently enabled.

Returns

True if API calls that require these capabillities will succeed.

Raises

UnknownCapabilityError – If a specified capability was not recognized.

will_remain_enabled_for(time=60)source

Returns whether a capability will remain enabled.

DEPRECATED: this method was never fully implemented and is considered deprecated. Use is_enabled() instead.

Parameters

time – Number of seconds in the future to look when checking for scheduled downtime.

Returns

True if there is no scheduled downtime for the specified capability within the amount of time specified.

Raises

UnknownCapabilityError – If a specified capability was not recognized.

exception google.appengine.api.capabilities.UnknownCapabilityErrorsource

Bases: exceptions.Exception

An unknown capability was requested.