type: google.api.Service
config_version: 1
name: longrunning.googleapis.com
title: Long Running Operations API

apis:
- name: google.longrunning.Operations

types:
- name: google.longrunning.OperationInfo

documentation:
  overview: |-
    # Long Running Operation API

    This package contains the definition of Long Running Operation (LRO)
    interface. It is a standard interface that API services can implement for
    managing asynchronous operations.

    ## What are Long Running Operations?

    A Long Running Operation (LRO) is a way of representing an action that may
    take a significant amount of time to complete. For example, an API call
    that starts exporting a large amount of data could take quite a while to
    complete and is therefore best represented as an LRO. A common rule of
    thumb is to think of LROs as "API promises" that represent the result of
    some on-going action.

    ## Using LROs

    If an API method could potentially take long time to finish, the method
    should return a long running operation instead of a direct response. This
    means that even if there are situations where the response could be
    immediate, the API should still return an LRO -- it just may be already
    marked as completed.
    For example, if a data export operation is called on an empty resource,
    the operation itself may be possible to execute immediately, and would
    result in an already completed LRO.

    Additionally, the operation should be managed using the LRO interface,
    which allows clients to poll the operation for status updates or cancel it
    entirely.

    Finally, an LRO represents an action and as a result, the operation is not
    created directly. Instead, the operation comes into existence as a
    side-effect of the action it represents. For example, an RPC called
    `ExportData` would
    create and return an LRO. This means that there should never be an RPC
    called `CreateOperation`.

    This also means that any permissions on the operation would be based on
    action it represents. Any immediate side effects of starting the operation
    must be visible in the service as soon as the LRO is returned. For
    example, if an LRO is returned when creating a resource, that resource
    should be visible in the API immediately, but be in a non-final state
    until the LRO is completed.

    ## LROs versus Jobs

    A job is a common design pattern often used in data processing that tends
    to be used to represent some contained piece of work that would be stored,
    re-run, and modified over time. Jobs also typically interact with multiple
    resources and are created, deleted, and updated directly as independent
    resources.

    Jobs can also offer support for more complex actions such as pausing and
    resuming an individual job, where each action could return an LRO as a
    response.

    In general, if an action may take a while but it represents a single piece
    of work, it's best to represent the response as an LRO. If the action is
    something more complex (for example, it involves lots of resources and
    can't be created as a byproduct of a single action), it may make more
    sense to represent it as a job.