By default, the task is sent to the service which is the default service when the task is attempted.
For some queues or tasks which were created using the App Engine Task Queue API, host is not parsable into service, version, and instance. For example, some tasks which were created using the App Engine SDK use a custom domain name; custom domains are not parsed by Cloud Tasks. If host is not parsable, then service, version, and instance are the empty string.
version
string
App version.
By default, the task is sent to the version which is the default version when the task is attempted.
For some queues or tasks which were created using the App Engine Task Queue API, host is not parsable into service, version, and instance. For example, some tasks which were created using the App Engine SDK use a custom domain name; custom domains are not parsed by Cloud Tasks. If host is not parsable, then service, version, and instance are the empty string.
instance
string
App instance.
By default, the task is sent to an instance which is available when the task is attempted.
The host is constructed from the domain name of the app associated with the queue's project ID (for example .appspot.com), and the service, version, and instance. Tasks which were created using the App Engine SDK might have a custom domain name.