// Copyright 2019 Google LLC.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

syntax = "proto3";

package google.cloud.tasks.v2;

import "google/api/annotations.proto";
import "google/api/resource.proto";
import "google/cloud/tasks/v2/target.proto";
import "google/protobuf/duration.proto";
import "google/protobuf/timestamp.proto";

option go_package = "google.golang.org/genproto/googleapis/cloud/tasks/v2;tasks";
option java_multiple_files = true;
option java_outer_classname = "QueueProto";
option java_package = "com.google.cloud.tasks.v2";


// A queue is a container of related tasks. Queues are configured to manage
// how those tasks are dispatched. Configurable properties include rate limits,
// retry options, queue types, and others.
message Queue {
  // State of the queue.
  enum State {
    // Unspecified state.
    STATE_UNSPECIFIED = 0;

    // The queue is running. Tasks can be dispatched.
    //
    // If the queue was created using Cloud Tasks and the queue has
    // had no activity (method calls or task dispatches) for 30 days,
    // the queue may take a few minutes to re-activate. Some method
    // calls may return [NOT_FOUND][google.rpc.Code.NOT_FOUND] and
    // tasks may not be dispatched for a few minutes until the queue
    // has been re-activated.
    RUNNING = 1;

    // Tasks are paused by the user. If the queue is paused then Cloud
    // Tasks will stop delivering tasks from it, but more tasks can
    // still be added to it by the user.
    PAUSED = 2;

    // The queue is disabled.
    //
    // A queue becomes `DISABLED` when
    // [queue.yaml](https://cloud.google.com/appengine/docs/python/config/queueref)
    // or
    // [queue.xml](https://cloud.google.com/appengine/docs/standard/java/config/queueref)
    // is uploaded which does not contain the queue. You cannot directly disable
    // a queue.
    //
    // When a queue is disabled, tasks can still be added to a queue
    // but the tasks are not dispatched.
    //
    // To permanently delete this queue and all of its tasks, call
    // [DeleteQueue][google.cloud.tasks.v2.CloudTasks.DeleteQueue].
    DISABLED = 3;
  }

  // Caller-specified and required in [CreateQueue][google.cloud.tasks.v2.CloudTasks.CreateQueue],
  // after which it becomes output only.
  //
  // The queue name.
  //
  // The queue name must have the following format:
  // `projects/PROJECT_ID/locations/LOCATION_ID/queues/QUEUE_ID`
  //
  // * `PROJECT_ID` can contain letters ([A-Za-z]), numbers ([0-9]),
  //    hyphens (-), colons (:), or periods (.).
  //    For more information, see
  //    [Identifying
  //    projects](https://cloud.google.com/resource-manager/docs/creating-managing-projects#identifying_projects)
  // * `LOCATION_ID` is the canonical ID for the queue's location.
  //    The list of available locations can be obtained by calling
  //    [ListLocations][google.cloud.location.Locations.ListLocations].
  //    For more information, see https://cloud.google.com/about/locations/.
  // * `QUEUE_ID` can contain letters ([A-Za-z]), numbers ([0-9]), or
  //   hyphens (-). The maximum length is 100 characters.
  string name = 1;

  // Overrides for
  // [task-level app_engine_routing][google.cloud.tasks.v2.AppEngineHttpRequest.app_engine_routing].
  // These settings apply only to
  // [App Engine tasks][google.cloud.tasks.v2.AppEngineHttpRequest] in this queue.
  //
  // If set, `app_engine_routing_override` is used for all
  // [App Engine tasks][google.cloud.tasks.v2.AppEngineHttpRequest] in the queue, no matter what the
  // setting is for the
  // [task-level app_engine_routing][google.cloud.tasks.v2.AppEngineHttpRequest.app_engine_routing].
  AppEngineRouting app_engine_routing_override = 2;

  // Rate limits for task dispatches.
  //
  // [rate_limits][google.cloud.tasks.v2.Queue.rate_limits] and [retry_config][google.cloud.tasks.v2.Queue.retry_config] are
  // related because they both control task attempts. However they control task
  // attempts in different ways:
  //
  // * [rate_limits][google.cloud.tasks.v2.Queue.rate_limits] controls the total rate of
  //   dispatches from a queue (i.e. all traffic dispatched from the
  //   queue, regardless of whether the dispatch is from a first
  //   attempt or a retry).
  // * [retry_config][google.cloud.tasks.v2.Queue.retry_config] controls what happens to
  //   particular a task after its first attempt fails. That is,
  //   [retry_config][google.cloud.tasks.v2.Queue.retry_config] controls task retries (the
  //   second attempt, third attempt, etc).
  //
  // The queue's actual dispatch rate is the result of:
  //
  // * Number of tasks in the queue
  // * User-specified throttling: [rate_limits][google.cloud.tasks.v2.Queue.rate_limits],
  //   [retry_config][google.cloud.tasks.v2.Queue.retry_config], and the
  //   [queue's state][google.cloud.tasks.v2.Queue.state].
  // * System throttling due to `429` (Too Many Requests) or `503` (Service
  //   Unavailable) responses from the worker, high error rates, or to smooth
  //   sudden large traffic spikes.
  RateLimits rate_limits = 3;

  // Settings that determine the retry behavior.
  //
  // * For tasks created using Cloud Tasks: the queue-level retry settings
  //   apply to all tasks in the queue that were created using Cloud Tasks.
  //   Retry settings cannot be set on individual tasks.
  // * For tasks created using the App Engine SDK: the queue-level retry
  //   settings apply to all tasks in the queue which do not have retry settings
  //   explicitly set on the task and were created by the App Engine SDK. See
  //   [App Engine
  //   documentation](https://cloud.google.com/appengine/docs/standard/python/taskqueue/push/retrying-tasks).
  RetryConfig retry_config = 4;

  // Output only. The state of the queue.
  //
  // `state` can only be changed by called
  // [PauseQueue][google.cloud.tasks.v2.CloudTasks.PauseQueue],
  // [ResumeQueue][google.cloud.tasks.v2.CloudTasks.ResumeQueue], or uploading
  // [queue.yaml/xml](https://cloud.google.com/appengine/docs/python/config/queueref).
  // [UpdateQueue][google.cloud.tasks.v2.CloudTasks.UpdateQueue] cannot be used to change `state`.
  State state = 5;

  // Output only. The last time this queue was purged.
  //
  // All tasks that were [created][google.cloud.tasks.v2.Task.create_time] before this time
  // were purged.
  //
  // A queue can be purged using [PurgeQueue][google.cloud.tasks.v2.CloudTasks.PurgeQueue], the
  // [App Engine Task Queue SDK, or the Cloud
  // Console](https://cloud.google.com/appengine/docs/standard/python/taskqueue/push/deleting-tasks-and-queues#purging_all_tasks_from_a_queue).
  //
  // Purge time will be truncated to the nearest microsecond. Purge
  // time will be unset if the queue has never been purged.
  google.protobuf.Timestamp purge_time = 6;
}

// Rate limits.
//
// This message determines the maximum rate that tasks can be dispatched by a
// queue, regardless of whether the dispatch is a first task attempt or a retry.
//
// Note: The debugging command, [RunTask][google.cloud.tasks.v2.CloudTasks.RunTask], will run a task
// even if the queue has reached its [RateLimits][google.cloud.tasks.v2.RateLimits].
message RateLimits {
  // The maximum rate at which tasks are dispatched from this queue.
  //
  // If unspecified when the queue is created, Cloud Tasks will pick the
  // default.
  //
  // * For [App Engine queues][google.cloud.tasks.v2.AppEngineHttpQueue], the maximum allowed value
  //   is 500.
  //
  //
  // This field has the same meaning as
  // [rate in
  // queue.yaml/xml](https://cloud.google.com/appengine/docs/standard/python/config/queueref#rate).
  double max_dispatches_per_second = 1;

  // Output only. The max burst size.
  //
  // Max burst size limits how fast tasks in queue are processed when
  // many tasks are in the queue and the rate is high. This field
  // allows the queue to have a high rate so processing starts shortly
  // after a task is enqueued, but still limits resource usage when
  // many tasks are enqueued in a short period of time.
  //
  // The [token bucket](https://wikipedia.org/wiki/Token_Bucket)
  // algorithm is used to control the rate of task dispatches. Each
  // queue has a token bucket that holds tokens, up to the maximum
  // specified by `max_burst_size`. Each time a task is dispatched, a
  // token is removed from the bucket. Tasks will be dispatched until
  // the queue's bucket runs out of tokens. The bucket will be
  // continuously refilled with new tokens based on
  // [max_dispatches_per_second][google.cloud.tasks.v2.RateLimits.max_dispatches_per_second].
  //
  // Cloud Tasks will pick the value of `max_burst_size` based on the
  // value of
  // [max_dispatches_per_second][google.cloud.tasks.v2.RateLimits.max_dispatches_per_second].
  //
  // For App Engine queues that were created or updated using
  // `queue.yaml/xml`, `max_burst_size` is equal to
  // [bucket_size](https://cloud.google.com/appengine/docs/standard/python/config/queueref#bucket_size).
  // Since `max_burst_size` is output only, if
  // [UpdateQueue][google.cloud.tasks.v2.CloudTasks.UpdateQueue] is called on a queue
  // created by `queue.yaml/xml`, `max_burst_size` will be reset based
  // on the value of
  // [max_dispatches_per_second][google.cloud.tasks.v2.RateLimits.max_dispatches_per_second],
  // regardless of whether
  // [max_dispatches_per_second][google.cloud.tasks.v2.RateLimits.max_dispatches_per_second]
  // is updated.
  //
  int32 max_burst_size = 2;

  // The maximum number of concurrent tasks that Cloud Tasks allows
  // to be dispatched for this queue. After this threshold has been
  // reached, Cloud Tasks stops dispatching tasks until the number of
  // concurrent requests decreases.
  //
  // If unspecified when the queue is created, Cloud Tasks will pick the
  // default.
  //
  //
  // The maximum allowed value is 5,000.
  //
  //
  // This field has the same meaning as
  // [max_concurrent_requests in
  // queue.yaml/xml](https://cloud.google.com/appengine/docs/standard/python/config/queueref#max_concurrent_requests).
  int32 max_concurrent_dispatches = 3;
}

// Retry config.
//
// These settings determine when a failed task attempt is retried.
message RetryConfig {
  // Number of attempts per task.
  //
  // Cloud Tasks will attempt the task `max_attempts` times (that is, if the
  // first attempt fails, then there will be `max_attempts - 1` retries). Must
  // be >= -1.
  //
  // If unspecified when the queue is created, Cloud Tasks will pick the
  // default.
  //
  // -1 indicates unlimited attempts.
  //
  // This field has the same meaning as
  // [task_retry_limit in
  // queue.yaml/xml](https://cloud.google.com/appengine/docs/standard/python/config/queueref#retry_parameters).
  int32 max_attempts = 1;

  // If positive, `max_retry_duration` specifies the time limit for
  // retrying a failed task, measured from when the task was first
  // attempted. Once `max_retry_duration` time has passed *and* the
  // task has been attempted [max_attempts][google.cloud.tasks.v2.RetryConfig.max_attempts]
  // times, no further attempts will be made and the task will be
  // deleted.
  //
  // If zero, then the task age is unlimited.
  //
  // If unspecified when the queue is created, Cloud Tasks will pick the
  // default.
  //
  //
  // `max_retry_duration` will be truncated to the nearest second.
  //
  // This field has the same meaning as
  // [task_age_limit in
  // queue.yaml/xml](https://cloud.google.com/appengine/docs/standard/python/config/queueref#retry_parameters).
  google.protobuf.Duration max_retry_duration = 2;

  // A task will be [scheduled][google.cloud.tasks.v2.Task.schedule_time] for retry between
  // [min_backoff][google.cloud.tasks.v2.RetryConfig.min_backoff] and
  // [max_backoff][google.cloud.tasks.v2.RetryConfig.max_backoff] duration after it fails,
  // if the queue's [RetryConfig][google.cloud.tasks.v2.RetryConfig] specifies that the task should be
  // retried.
  //
  // If unspecified when the queue is created, Cloud Tasks will pick the
  // default.
  //
  //
  // `min_backoff` will be truncated to the nearest second.
  //
  // This field has the same meaning as
  // [min_backoff_seconds in
  // queue.yaml/xml](https://cloud.google.com/appengine/docs/standard/python/config/queueref#retry_parameters).
  google.protobuf.Duration min_backoff = 3;

  // A task will be [scheduled][google.cloud.tasks.v2.Task.schedule_time] for retry between
  // [min_backoff][google.cloud.tasks.v2.RetryConfig.min_backoff] and
  // [max_backoff][google.cloud.tasks.v2.RetryConfig.max_backoff] duration after it fails,
  // if the queue's [RetryConfig][google.cloud.tasks.v2.RetryConfig] specifies that the task should be
  // retried.
  //
  // If unspecified when the queue is created, Cloud Tasks will pick the
  // default.
  //
  //
  // `max_backoff` will be truncated to the nearest second.
  //
  // This field has the same meaning as
  // [max_backoff_seconds in
  // queue.yaml/xml](https://cloud.google.com/appengine/docs/standard/python/config/queueref#retry_parameters).
  google.protobuf.Duration max_backoff = 4;

  // The time between retries will double `max_doublings` times.
  //
  // A task's retry interval starts at
  // [min_backoff][google.cloud.tasks.v2.RetryConfig.min_backoff], then doubles
  // `max_doublings` times, then increases linearly, and finally
  // retries retries at intervals of
  // [max_backoff][google.cloud.tasks.v2.RetryConfig.max_backoff] up to
  // [max_attempts][google.cloud.tasks.v2.RetryConfig.max_attempts] times.
  //
  // For example, if [min_backoff][google.cloud.tasks.v2.RetryConfig.min_backoff] is 10s,
  // [max_backoff][google.cloud.tasks.v2.RetryConfig.max_backoff] is 300s, and
  // `max_doublings` is 3, then the a task will first be retried in
  // 10s. The retry interval will double three times, and then
  // increase linearly by 2^3 * 10s.  Finally, the task will retry at
  // intervals of [max_backoff][google.cloud.tasks.v2.RetryConfig.max_backoff] until the
  // task has been attempted [max_attempts][google.cloud.tasks.v2.RetryConfig.max_attempts]
  // times. Thus, the requests will retry at 10s, 20s, 40s, 80s, 160s,
  // 240s, 300s, 300s, ....
  //
  // If unspecified when the queue is created, Cloud Tasks will pick the
  // default.
  //
  //
  // This field has the same meaning as
  // [max_doublings in
  // queue.yaml/xml](https://cloud.google.com/appengine/docs/standard/python/config/queueref#retry_parameters).
  int32 max_doublings = 5;
}
