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// Specification of the Pubsub API. |
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syntax = "proto2"; |
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import "examples/tips/empty.proto"; |
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import "examples/tips/label.proto"; |
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package tech.pubsub; |
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// ----------------------------------------------------------------------------- |
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// Overview of the Pubsub API |
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// ----------------------------------------------------------------------------- |
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// This file describes an API for a Pubsub system. This system provides a |
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// reliable many-to-many communication mechanism between independently written |
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// publishers and subscribers where the publisher publishes messages to "topics" |
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// and each subscriber creates a "subscription" and consumes messages from it. |
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// |
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// (a) The pubsub system maintains bindings between topics and subscriptions. |
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// (b) A publisher publishes messages into a topic. |
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// (c) The pubsub system delivers messages from topics into relevant |
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// subscriptions. |
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// (d) A subscriber receives pending messages from its subscription and |
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// acknowledges or nacks each one to the pubsub system. |
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// (e) The pubsub system removes acknowledged messages from that subscription. |
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// ----------------------------------------------------------------------------- |
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// Data Model |
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// ----------------------------------------------------------------------------- |
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// The data model consists of the following: |
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// |
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// * Topic: A topic is a resource to which messages are published by publishers. |
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// Topics are named, and the name of the topic is unique within the pubsub |
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// system. |
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// |
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// * Subscription: A subscription records the subscriber's interest in a topic. |
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// It can optionally include a query to select a subset of interesting |
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// messages. The pubsub system maintains a logical cursor tracking the |
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// matching messages which still need to be delivered and acked so that |
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// they can retried as needed. The set of messages that have not been |
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// acknowledged is called the subscription backlog. |
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// |
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// * Message: A message is a unit of data that flows in the system. It contains |
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// opaque data from the publisher along with its labels. |
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// |
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// * Message Labels (optional): A set of opaque key, value pairs assigned |
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// by the publisher which the subscriber can use for filtering out messages |
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// in the topic. For example, a label with key "foo.com/device_type" and |
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// value "mobile" may be added for messages that are only relevant for a |
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// mobile subscriber; a subscriber on a phone may decide to create a |
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// subscription only for messages that have this label. |
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// ----------------------------------------------------------------------------- |
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// Publisher Flow |
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// ----------------------------------------------------------------------------- |
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// A publisher publishes messages to the topic using the Publish request: |
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// |
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// PubsubMessage message; |
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// message.set_data("...."); |
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// Label label; |
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// label.set_key("foo.com/key1"); |
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// label.set_str_value("value1"); |
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// message.add_label(label); |
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// PublishRequest request; |
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// request.set_topic("topicName"); |
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// request.set_message(message); |
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// PublisherService.Publish(request); |
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// ----------------------------------------------------------------------------- |
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// Subscriber Flow |
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// ----------------------------------------------------------------------------- |
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// The subscriber part of the API is richer than the publisher part and has a |
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// number of concepts w.r.t. subscription creation and monitoring: |
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// |
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// (1) A subscriber creates a subscription using the CreateSubscription call. |
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// It may specify an optional "query" to indicate that it wants to receive |
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// only messages with a certain set of labels using the label query syntax. |
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// It may also specify an optional truncation policy to indicate when old |
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// messages from the subcription can be removed. |
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// |
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// (2) A subscriber receives messages in one of two ways: via push or pull. |
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// |
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// (a) To receive messages via push, the PushConfig field must be specified in |
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// the Subscription parameter when creating a subscription. The PushConfig |
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// specifies an endpoint at which the subscriber must expose the |
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// PushEndpointService. Messages are received via the HandlePubsubEvent |
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// method. The push subscriber responds to the HandlePubsubEvent method |
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// with a result code that indicates one of three things: Ack (the message |
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// has been successfully processed and the Pubsub system may delete it), |
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// Nack (the message has been rejected, the Pubsub system should resend it |
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// at a later time), or Push-Back (this is a Nack with the additional |
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// semantics that the subscriber is overloaded and the pubsub system should |
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// back off on the rate at which it is invoking HandlePubsubEvent). The |
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// endpoint may be a load balancer for better scalability. |
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// |
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// (b) To receive messages via pull a subscriber calls the Pull method on the |
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// SubscriberService to get messages from the subscription. For each |
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// individual message, the subscriber may use the ack_id received in the |
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// PullResponse to Ack the message, Nack the message, or modify the ack |
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// deadline with ModifyAckDeadline. See the |
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// Subscription.ack_deadline_seconds field documentation for details on the |
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// ack deadline behavior. |
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// |
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// Note: Messages may be consumed in parallel by multiple subscribers making |
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// Pull calls to the same subscription; this will result in the set of |
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// messages from the subscription being shared and each subscriber |
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// receiving a subset of the messages. |
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// |
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// (4) The subscriber can explicitly truncate the current subscription. |
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// |
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// (5) "Truncated" events are delivered when a subscription is |
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// truncated, whether due to the subscription's truncation policy |
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// or an explicit request from the subscriber. |
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// |
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// Subscription creation: |
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// |
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// Subscription subscription; |
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// subscription.set_topic("topicName"); |
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// subscription.set_name("subscriptionName"); |
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// subscription.push_config().set_push_endpoint("machinename:8888"); |
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// SubscriberService.CreateSubscription(subscription); |
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// |
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// Consuming messages via push: |
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// |
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// TODO(eschapira): Add HTTP push example. |
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// |
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// The port 'machinename:8888' must be bound to a stubby server that implements |
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// the PushEndpointService with the following method: |
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// |
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// int HandlePubsubEvent(PubsubEvent event) { |
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// if (event.subscription().equals("subscriptionName")) { |
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// if (event.has_message()) { |
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// Process(event.message().data()); |
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// } else if (event.truncated()) { |
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// ProcessTruncatedEvent(); |
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// } |
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// } |
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// return OK; // This return code implies an acknowledgment |
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// } |
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// |
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// Consuming messages via pull: |
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// |
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// The subscription must be created without setting the push_config field. |
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// |
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// PullRequest pull_request; |
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// pull_request.set_subscription("subscriptionName"); |
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// pull_request.set_return_immediately(false); |
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// while (true) { |
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// PullResponse pull_response; |
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// if (SubscriberService.Pull(pull_request, pull_response) == OK) { |
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// PubsubEvent event = pull_response.pubsub_event(); |
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// if (event.has_message()) { |
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// Process(event.message().data()); |
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// } else if (event.truncated()) { |
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// ProcessTruncatedEvent(); |
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// } |
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// AcknowledgeRequest ack_request; |
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// ackRequest.set_subscription("subscriptionName"); |
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// ackRequest.set_ack_id(pull_response.ack_id()); |
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// SubscriberService.Acknowledge(ack_request); |
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// } |
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// } |
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// ----------------------------------------------------------------------------- |
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// Reliability Semantics |
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// ----------------------------------------------------------------------------- |
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// When a subscriber successfully creates a subscription using |
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// Subscriber.CreateSubscription, it establishes a "subscription point" with |
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// respect to that subscription - the subscriber is guaranteed to receive any |
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// message published after this subscription point that matches the |
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// subscription's query. Note that messages published before the Subscription |
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// point may or may not be delivered. |
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// |
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// If the system truncates the subscription according to the specified |
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// truncation policy, the system delivers a subscription status event with the |
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// "truncated" field set to true. We refer to such events as "truncation |
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// events". A truncation event: |
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// |
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// * Informs the subscriber that part of the subscription messages have been |
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// discarded. The subscriber may want to recover from the message loss, e.g., |
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// by resyncing its state with its backend. |
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// * Establishes a new subscription point, i.e., the subscriber is guaranteed to |
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// receive all changes published after the trunction event is received (or |
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// until another truncation event is received). |
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// |
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// Note that messages are not delivered in any particular order by the pubsub |
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// system. Furthermore, the system guarantees at-least-once delivery |
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// of each message or truncation events until acked. |
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// ----------------------------------------------------------------------------- |
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// Deletion |
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// ----------------------------------------------------------------------------- |
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// Both topics and subscriptions may be deleted. Deletion of a topic implies |
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// deletion of all attached subscriptions. |
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// |
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// When a subscription is deleted directly by calling DeleteSubscription, all |
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// messages are immediately dropped. If it is a pull subscriber, future pull |
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// requests will return NOT_FOUND. |
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// |
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// When a topic is deleted all corresponding subscriptions are immediately |
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// deleted, and subscribers experience the same behavior as directly deleting |
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// the subscription. |
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// ----------------------------------------------------------------------------- |
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// The Publisher service and its protos. |
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// ----------------------------------------------------------------------------- |
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// The service that an application uses to manipulate topics, and to send |
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// messages to a topic. |
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service PublisherService { |
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// Creates the given topic with the given name. |
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rpc CreateTopic(Topic) returns (Topic) { |
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} |
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// Adds a message to the topic. Returns NOT_FOUND if the topic does not |
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// exist. |
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// (-- For different error code values returned via Stubby, see |
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// util/task/codes.proto. --) |
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rpc Publish(PublishRequest) returns (proto2.Empty) { |
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} |
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// Adds one or more messages to the topic. Returns NOT_FOUND if the topic does |
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// not exist. |
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rpc PublishBatch(PublishBatchRequest) returns (PublishBatchResponse) { |
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} |
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// Gets the configuration of a topic. Since the topic only has the name |
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// attribute, this method is only useful to check the existence of a topic. |
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// If other attributes are added in the future, they will be returned here. |
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rpc GetTopic(GetTopicRequest) returns (Topic) { |
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} |
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// Lists matching topics. |
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rpc ListTopics(ListTopicsRequest) returns (ListTopicsResponse) { |
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} |
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// Deletes the topic with the given name. All subscriptions to this topic |
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// are also deleted. Returns NOT_FOUND if the topic does not exist. |
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// After a topic is deleted, a new topic may be created with the same name. |
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rpc DeleteTopic(DeleteTopicRequest) returns (proto2.Empty) { |
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} |
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} |
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// A topic resource. |
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message Topic { |
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// Name of the topic. |
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optional string name = 1; |
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} |
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// A message data and its labels. |
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message PubsubMessage { |
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// The message payload. |
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optional bytes data = 1; |
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// Optional list of labels for this message. Keys in this collection must |
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// be unique. |
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//(-- TODO(eschapira): Define how key namespace may be scoped to the topic.--) |
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repeated tech.label.Label label = 2; |
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// ID of this message assigned by the server at publication time. Guaranteed |
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// to be unique within the topic. This value may be read by a subscriber |
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// that receives a PubsubMessage via a Pull call or a push delivery. It must |
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// not be populated by a publisher in a Publish call. |
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optional string message_id = 3; |
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} |
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// Request for the GetTopic method. |
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message GetTopicRequest { |
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// The name of the topic to get. |
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optional string topic = 1; |
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} |
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// Request for the Publish method. |
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message PublishRequest { |
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// The message in the request will be published on this topic. |
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optional string topic = 1; |
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// The message to publish. |
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optional PubsubMessage message = 2; |
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} |
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// Request for the PublishBatch method. |
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message PublishBatchRequest { |
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// The messages in the request will be published on this topic. |
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optional string topic = 1; |
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// The messages to publish. |
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repeated PubsubMessage messages = 2; |
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} |
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// Response for the PublishBatch method. |
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message PublishBatchResponse { |
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// The server-assigned ID of each published message, in the same order as |
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// the messages in the request. IDs are guaranteed to be unique within |
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// the topic. |
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repeated string message_ids = 1; |
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} |
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// Request for the ListTopics method. |
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message ListTopicsRequest { |
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// A valid label query expression. |
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// (-- Which labels are required or supported is implementation-specific. --) |
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optional string query = 1; |
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// Maximum number of topics to return. |
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// (-- If not specified or <= 0, the implementation will select a reasonable |
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// value. --) |
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optional int32 max_results = 2; |
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// The value obtained in the last <code>ListTopicsResponse</code> |
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// for continuation. |
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optional string page_token = 3; |
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} |
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// Response for the ListTopics method. |
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message ListTopicsResponse { |
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// The resulting topics. |
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repeated Topic topic = 1; |
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// If not empty, indicates that there are more topics that match the request, |
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// and this value should be passed to the next <code>ListTopicsRequest</code> |
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// to continue. |
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optional string next_page_token = 2; |
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} |
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// Request for the Delete method. |
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message DeleteTopicRequest { |
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// Name of the topic to delete. |
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optional string topic = 1; |
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} |
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// ----------------------------------------------------------------------------- |
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// The Subscriber service and its protos. |
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// ----------------------------------------------------------------------------- |
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// The service that an application uses to manipulate subscriptions and to |
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// consume messages from a subscription via the pull method. |
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service SubscriberService { |
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// Creates a subscription on a given topic for a given subscriber. |
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// If the subscription already exists, returns ALREADY_EXISTS. |
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// If the corresponding topic doesn't exist, returns NOT_FOUND. |
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// |
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// If the name is not provided in the request, the server will assign a random |
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// name for this subscription on the same project as the topic. |
|
|
|
|
rpc CreateSubscription(Subscription) returns (Subscription) { |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// Gets the configuration details of a subscription. |
|
|
|
|
rpc GetSubscription(GetSubscriptionRequest) returns (Subscription) { |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// Lists matching subscriptions. |
|
|
|
|
rpc ListSubscriptions(ListSubscriptionsRequest) |
|
|
|
|
returns (ListSubscriptionsResponse) { |
|
|
|
|
} |
|
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|
|
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|
|
|
// Deletes an existing subscription. All pending messages in the subscription |
|
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|
|
// are immediately dropped. Calls to Pull after deletion will return |
|
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|
|
// NOT_FOUND. |
|
|
|
|
rpc DeleteSubscription(DeleteSubscriptionRequest) returns (proto2.Empty) { |
|
|
|
|
} |
|
|
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|
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|
|
// Removes all the pending messages in the subscription and releases the |
|
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|
|
// storage associated with them. Results in a truncation event to be sent to |
|
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|
|
// the subscriber. Messages added after this call returns are stored in the |
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|
|
// subscription as before. |
|
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|
|
rpc TruncateSubscription(TruncateSubscriptionRequest) returns (proto2.Empty) { |
|
|
|
|
} |
|
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|
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|
|
// |
|
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|
|
// Push subscriber calls. |
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|
|
// |
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|
|
// Modifies the <code>PushConfig</code> for a specified subscription. |
|
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|
|
// This method can be used to suspend the flow of messages to an endpoint |
|
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|
|
// by clearing the <code>PushConfig</code> field in the request. Messages |
|
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|
|
// will be accumulated for delivery even if no push configuration is |
|
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|
|
// defined or while the configuration is modified. |
|
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|
|
rpc ModifyPushConfig(ModifyPushConfigRequest) returns (proto2.Empty) { |
|
|
|
|
} |
|
|
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|
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|
|
// |
|
|
|
|
// Pull Subscriber calls |
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|
|
// |
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|
|
// Pulls a single message from the server. |
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|
|
// If return_immediately is true, and no messages are available in the |
|
|
|
|
// subscription, this method returns FAILED_PRECONDITION. The system is free |
|
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|
|
// to return an UNAVAILABLE error if no messages are available in a |
|
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|
|
// reasonable amount of time (to reduce system load). |
|
|
|
|
rpc Pull(PullRequest) returns (PullResponse) { |
|
|
|
|
} |
|
|
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|
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|
|
|
|
// Pulls messages from the server. Returns an empty list if there are no |
|
|
|
|
// messages available in the backlog. The system is free to return UNAVAILABLE |
|
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|
|
// if there are too many pull requests outstanding for the given subscription. |
|
|
|
|
rpc PullBatch(PullBatchRequest) returns (PullBatchResponse) { |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// Modifies the Ack deadline for a message received from a pull request. |
|
|
|
|
rpc ModifyAckDeadline(ModifyAckDeadlineRequest) returns (proto2.Empty) { |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// Acknowledges a particular received message: the Pub/Sub system can remove |
|
|
|
|
// the given message from the subscription. Acknowledging a message whose |
|
|
|
|
// Ack deadline has expired may succeed, but the message could have been |
|
|
|
|
// already redelivered. Acknowledging a message more than once will not |
|
|
|
|
// result in an error. This is only used for messages received via pull. |
|
|
|
|
rpc Acknowledge(AcknowledgeRequest) returns (proto2.Empty) { |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// Refuses processing a particular received message. The system will |
|
|
|
|
// redeliver this message to some consumer of the subscription at some |
|
|
|
|
// future time. This is only used for messages received via pull. |
|
|
|
|
rpc Nack(NackRequest) returns (proto2.Empty) { |
|
|
|
|
} |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// A subscription resource. |
|
|
|
|
message Subscription { |
|
|
|
|
// Name of the subscription. |
|
|
|
|
optional string name = 1; |
|
|
|
|
|
|
|
|
|
// The name of the topic from which this subscription is receiving messages. |
|
|
|
|
optional string topic = 2; |
|
|
|
|
|
|
|
|
|
// If <code>query</code> is non-empty, only messages on the subscriber's |
|
|
|
|
// topic whose labels match the query will be returned. Otherwise all |
|
|
|
|
// messages on the topic will be returned. |
|
|
|
|
// (-- The query syntax is described in tech/label/proto/label_query.proto --) |
|
|
|
|
optional string query = 3; |
|
|
|
|
|
|
|
|
|
// The subscriber may specify requirements for truncating unacknowledged |
|
|
|
|
// subscription entries. The system will honor the |
|
|
|
|
// <code>CreateSubscription</code> request only if it can meet these |
|
|
|
|
// requirements. If this field is not specified, messages are never truncated |
|
|
|
|
// by the system. |
|
|
|
|
optional TruncationPolicy truncation_policy = 4; |
|
|
|
|
|
|
|
|
|
// Specifies which messages can be truncated by the system. |
|
|
|
|
message TruncationPolicy { |
|
|
|
|
oneof policy { |
|
|
|
|
// If <code>max_bytes</code> is specified, the system is allowed to drop |
|
|
|
|
// old messages to keep the combined size of stored messages under |
|
|
|
|
// <code>max_bytes</code>. This is a hint; the system may keep more than |
|
|
|
|
// this many bytes, but will make a best effort to keep the size from |
|
|
|
|
// growing much beyond this parameter. |
|
|
|
|
int64 max_bytes = 1; |
|
|
|
|
|
|
|
|
|
// If <code>max_age_seconds</code> is specified, the system is allowed to |
|
|
|
|
// drop messages that have been stored for at least this many seconds. |
|
|
|
|
// This is a hint; the system may keep these messages, but will make a |
|
|
|
|
// best effort to remove them when their maximum age is reached. |
|
|
|
|
int64 max_age_seconds = 2; |
|
|
|
|
} |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// If push delivery is used with this subscription, this field is |
|
|
|
|
// used to configure it. |
|
|
|
|
optional PushConfig push_config = 5; |
|
|
|
|
|
|
|
|
|
// For either push or pull delivery, the value is the maximum time after a |
|
|
|
|
// subscriber receives a message before the subscriber should acknowledge or |
|
|
|
|
// Nack the message. If the Ack deadline for a message passes without an |
|
|
|
|
// Ack or a Nack, the Pub/Sub system will eventually redeliver the message. |
|
|
|
|
// If a subscriber acknowledges after the deadline, the Pub/Sub system may |
|
|
|
|
// accept the Ack, but it is possible that the message has been already |
|
|
|
|
// delivered again. Multiple Acks to the message are allowed and will |
|
|
|
|
// succeed. |
|
|
|
|
// |
|
|
|
|
// For push delivery, this value is used to set the request timeout for |
|
|
|
|
// the call to the push endpoint. |
|
|
|
|
// |
|
|
|
|
// For pull delivery, this value is used as the initial value for the Ack |
|
|
|
|
// deadline. It may be overridden for a specific pull request (message) with |
|
|
|
|
// <code>ModifyAckDeadline</code>. |
|
|
|
|
// While a message is outstanding (i.e. it has been delivered to a pull |
|
|
|
|
// subscriber and the subscriber has not yet Acked or Nacked), the Pub/Sub |
|
|
|
|
// system will not deliver that message to another pull subscriber |
|
|
|
|
// (on a best-effort basis). |
|
|
|
|
optional int32 ack_deadline_seconds = 6; |
|
|
|
|
|
|
|
|
|
// If this parameter is set to n, the system is allowed to (but not required |
|
|
|
|
// to) delete the subscription when at least n seconds have elapsed since the |
|
|
|
|
// client presence was detected. (Presence is detected through any |
|
|
|
|
// interaction using the subscription ID, including Pull(), Get(), or |
|
|
|
|
// acknowledging a message.) |
|
|
|
|
// |
|
|
|
|
// If this parameter is not set, the subscription will stay live until |
|
|
|
|
// explicitly deleted. |
|
|
|
|
// |
|
|
|
|
// Clients can detect such garbage collection when a Get call or a Pull call |
|
|
|
|
// (for pull subscribers only) returns NOT_FOUND. |
|
|
|
|
optional int64 garbage_collect_seconds = 7; |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// Configuration for a push delivery endpoint. |
|
|
|
|
message PushConfig { |
|
|
|
|
// A URL locating the endpoint to which messages should be pushed. |
|
|
|
|
// For example, a Webhook endpoint might use "https://example.com/push". |
|
|
|
|
// (-- An Android application might use "gcm:<REGID>", where <REGID> is a |
|
|
|
|
// GCM registration id allocated for pushing messages to the application. --) |
|
|
|
|
optional string push_endpoint = 1; |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// An event indicating a received message or truncation event. |
|
|
|
|
message PubsubEvent { |
|
|
|
|
// The subscription that received the event. |
|
|
|
|
optional string subscription = 1; |
|
|
|
|
|
|
|
|
|
oneof type { |
|
|
|
|
// A received message. |
|
|
|
|
PubsubMessage message = 2; |
|
|
|
|
|
|
|
|
|
// Indicates that this subscription has been truncated. |
|
|
|
|
bool truncated = 3; |
|
|
|
|
|
|
|
|
|
// Indicates that this subscription has been deleted. (Note that pull |
|
|
|
|
// subscribers will always receive NOT_FOUND in response in their pull |
|
|
|
|
// request on the subscription, rather than seeing this boolean.) |
|
|
|
|
bool deleted = 4; |
|
|
|
|
} |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// Request for the GetSubscription method. |
|
|
|
|
message GetSubscriptionRequest { |
|
|
|
|
// The name of the subscription to get. |
|
|
|
|
optional string subscription = 1; |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// Request for the ListSubscriptions method. |
|
|
|
|
message ListSubscriptionsRequest { |
|
|
|
|
// A valid label query expression. |
|
|
|
|
// (-- Which labels are required or supported is implementation-specific. |
|
|
|
|
// TODO(eschapira): This method must support to query by topic. We must |
|
|
|
|
// define the key URI for the "topic" label. --) |
|
|
|
|
optional string query = 1; |
|
|
|
|
|
|
|
|
|
// Maximum number of subscriptions to return. |
|
|
|
|
// (-- If not specified or <= 0, the implementation will select a reasonable |
|
|
|
|
// value. --) |
|
|
|
|
optional int32 max_results = 3; |
|
|
|
|
|
|
|
|
|
// The value obtained in the last <code>ListSubscriptionsResponse</code> |
|
|
|
|
// for continuation. |
|
|
|
|
optional string page_token = 4; |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// Response for the ListSubscriptions method. |
|
|
|
|
message ListSubscriptionsResponse { |
|
|
|
|
// The subscriptions that match the request. |
|
|
|
|
repeated Subscription subscription = 1; |
|
|
|
|
|
|
|
|
|
// If not empty, indicates that there are more subscriptions that match the |
|
|
|
|
// request and this value should be passed to the next |
|
|
|
|
// <code>ListSubscriptionsRequest</code> to continue. |
|
|
|
|
optional string next_page_token = 2; |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// Request for the TruncateSubscription method. |
|
|
|
|
message TruncateSubscriptionRequest { |
|
|
|
|
// The subscription that is being truncated. |
|
|
|
|
optional string subscription = 1; |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// Request for the DeleteSubscription method. |
|
|
|
|
message DeleteSubscriptionRequest { |
|
|
|
|
// The subscription to delete. |
|
|
|
|
optional string subscription = 1; |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// Request for the ModifyPushConfig method. |
|
|
|
|
message ModifyPushConfigRequest { |
|
|
|
|
// The name of the subscription. |
|
|
|
|
optional string subscription = 1; |
|
|
|
|
|
|
|
|
|
// An empty <code>push_config</code> indicates that the Pub/Sub system should |
|
|
|
|
// pause pushing messages from the given subscription. |
|
|
|
|
optional PushConfig push_config = 2; |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// ----------------------------------------------------------------------------- |
|
|
|
|
// The protos used by a pull subscriber. |
|
|
|
|
// ----------------------------------------------------------------------------- |
|
|
|
|
|
|
|
|
|
// Request for the Pull method. |
|
|
|
|
message PullRequest { |
|
|
|
|
// The subscription from which a message should be pulled. |
|
|
|
|
optional string subscription = 1; |
|
|
|
|
|
|
|
|
|
// If this is specified as true the system will respond immediately even if |
|
|
|
|
// it is not able to return a message in the Pull response. Otherwise the |
|
|
|
|
// system is allowed to wait until at least one message is available rather |
|
|
|
|
// than returning FAILED_PRECONDITION. The client may cancel the request if |
|
|
|
|
// it does not wish to wait any longer for the response. |
|
|
|
|
optional bool return_immediately = 2; |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// Either a <code>PubsubMessage</code> or a truncation event. One of these two |
|
|
|
|
// must be populated. |
|
|
|
|
message PullResponse { |
|
|
|
|
// This ID must be used to acknowledge the received event or message. |
|
|
|
|
optional string ack_id = 1; |
|
|
|
|
|
|
|
|
|
// A pubsub message or truncation event. |
|
|
|
|
optional PubsubEvent pubsub_event = 2; |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// Request for the PullBatch method. |
|
|
|
|
message PullBatchRequest { |
|
|
|
|
// The subscription from which messages should be pulled. |
|
|
|
|
optional string subscription = 1; |
|
|
|
|
|
|
|
|
|
// If this is specified as true the system will respond immediately even if |
|
|
|
|
// it is not able to return a message in the Pull response. Otherwise the |
|
|
|
|
// system is allowed to wait until at least one message is available rather |
|
|
|
|
// than returning no messages. The client may cancel the request if it does |
|
|
|
|
// not wish to wait any longer for the response. |
|
|
|
|
optional bool return_immediately = 2; |
|
|
|
|
|
|
|
|
|
// The maximum number of PubsubEvents returned for this request. The Pub/Sub |
|
|
|
|
// system may return fewer than the number of events specified. |
|
|
|
|
optional int32 max_events = 3; |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// Response for the PullBatch method. |
|
|
|
|
message PullBatchResponse { |
|
|
|
|
|
|
|
|
|
// Received Pub/Sub messages or status events. The Pub/Sub system will return |
|
|
|
|
// zero messages if there are no more messages available in the backlog. The |
|
|
|
|
// Pub/Sub system may return fewer than the max_events requested even if |
|
|
|
|
// there are more messages available in the backlog. |
|
|
|
|
repeated PullResponse pull_responses = 2; |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// Request for the ModifyAckDeadline method. |
|
|
|
|
message ModifyAckDeadlineRequest { |
|
|
|
|
// The name of the subscription from which messages are being pulled. |
|
|
|
|
optional string subscription = 1; |
|
|
|
|
|
|
|
|
|
// The acknowledgment ID. |
|
|
|
|
optional string ack_id = 2; |
|
|
|
|
|
|
|
|
|
// The new Ack deadline. Must be >= 0. |
|
|
|
|
optional int32 ack_deadline_seconds = 3; |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// Request for the Acknowledge method. |
|
|
|
|
message AcknowledgeRequest { |
|
|
|
|
// The subscription whose message is being acknowledged. |
|
|
|
|
optional string subscription = 1; |
|
|
|
|
|
|
|
|
|
// The acknowledgment ID for the message being acknowledged. This was |
|
|
|
|
// returned by the Pub/Sub system in the Pull response. |
|
|
|
|
repeated string ack_id = 2; |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// Request for the Nack method. |
|
|
|
|
message NackRequest { |
|
|
|
|
// The subscription whose message is being Nacked. |
|
|
|
|
optional string subscription = 1; |
|
|
|
|
|
|
|
|
|
// The acknowledgment ID for the message being refused. This was returned by |
|
|
|
|
// the Pub/Sub system in the Pull response. |
|
|
|
|
repeated string ack_id = 2; |
|
|
|
|
} |
|
|
|
|
|
|
|
|
|
// ----------------------------------------------------------------------------- |
|
|
|
|
// The service and protos used by a push subscriber. |
|
|
|
|
// ----------------------------------------------------------------------------- |
|
|
|
|
|
|
|
|
|
// The service that a subscriber uses to handle messages sent via push |
|
|
|
|
// delivery. |
|
|
|
|
// This service is not currently exported for HTTP clients. |
|
|
|
|
// TODO(eschapira): Explain HTTP subscribers. |
|
|
|
|
service PushEndpointService { |
|
|
|
|
// Sends a <code>PubsubMessage</code> or a subscription status event to a |
|
|
|
|
// push endpoint. |
|
|
|
|
// The push endpoint responds with an empty message and a code from |
|
|
|
|
// util/task/codes.proto. The following codes have a particular meaning to the |
|
|
|
|
// Pub/Sub system: |
|
|
|
|
// OK - This is interpreted by Pub/Sub as Ack. |
|
|
|
|
// ABORTED - This is intepreted by Pub/Sub as a Nack, without implying |
|
|
|
|
// pushback for congestion control. The Pub/Sub system will |
|
|
|
|
// retry this message at a later time. |
|
|
|
|
// UNAVAILABLE - This is intepreted by Pub/Sub as a Nack, with the additional |
|
|
|
|
// semantics of push-back. The Pub/Sub system will use an AIMD |
|
|
|
|
// congestion control algorithm to backoff the rate of sending |
|
|
|
|
// messages from this subscription. |
|
|
|
|
// Any other code, or a failure to respond, will be interpreted in the same |
|
|
|
|
// way as ABORTED; i.e. the system will retry the message at a later time to |
|
|
|
|
// ensure reliable delivery. |
|
|
|
|
rpc HandlePubsubEvent(PubsubEvent) returns (proto2.Empty); |
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} |
Yang Gao
10 years ago