We ran into this issues a few times and hope to find a workaround.
screenshot of Cloud PubSub web console
As in the picture, the PubSub topic has a push subscription on it. When 'VIEW MESSAGES' was clicked, the side panel seemed to allow the user to choose a subscription. But when the user clicked on it, it was not showing the subscription. As a result, the user was not able to 'view messages'.
Is the type of subscription related to this issue or is this functionality not available? If it is related, is there a way to see messages for a topic with only a push subscription?
A push subscription don't stack the message. Each time there is a message, the push subscription sent it to the HTTP endpoint. Because of this, the subscription is always "empty".(This is not exactly true, the not acked message are in memory and are retried until the reception of HTTP code 2XX of the TTL expiration (7 days by default). But there is nothing really stored, at rest)
At the opposite, the pull subscription stack the message until the polling by a client. By the way, you can see the messages stacked.
When I debug a push subscription, especially for seeing what is the structure, the type of message and to validate this, I create a pull subscription in addition and I look into it the messages published in the topic.
Related
In my understanding PubSub filters are supposed to reduce number of messages sent to a specific subscription. We currently observe behaviour that we didn't expect.
Assuming there is a PubSub Topic "XYZ" and a subscription to that topic "XYZ-Sub" with a filter attributes.someHeader = "x"
There are 2 messages published to that topic:
First one attributes.someHeader = "a". Second one with attributes.someHeader = "x"
I expect the only message 2 will be delivered to the subscription as message 1 does not match the filter.
If it is not the case and still both messages get delivered (what we currently observe):
GCP console shows a rising number of unacked messages on a sub when no client is connected. Pulling this messages in the gcp console removes them without showing any received messages, which makes me assume that the filters are applied when pulling messages.
Are filters evaluated on PubSub client and not topic level?
What is the point in using filters with pub/sub?
Will the delivery of the unwanted message (the bytes of the message) be billed?
Filtering in Cloud Pub/Sub only delivers messages that match the filter to subscribers. The filters are applied in the Pub/Sub service itself, not in the client. They allow you to limit the set of messages delivered to subscribers when the subscriber only wants to process a subset of the messages.
In your example, only the message with attributes.someHeader = "x" should be delivered. However, note that as the documentation, the backlog metrics might include messages that don't match the filter. Such messages will not be delivered to subscribers, but may still show up in the backlog metrics for a time.
You do get charged the Pub/Sub message delivery price for messages that were not delivered. However, you do not pay any network fees for them, nor do you end up paying for any compute to process messages you do not receive.
Problem: My use case is I want to publish thousends of messages to Google Cloud Pub/Sub with a 5min retention period but only retrieve specific messages by their ID - So a cloud function will retrieve one message by ID using the Nodejs SDK and all the untreated messages will be deleted by the retention policy. All the current examples mention are to handle random messages from the subscriber.
Is it possible to just pull 1 message by id or any other metadata and close the connection.
There is no way to retrieve individual messages by ID, no. It doesn't really fit into the expected use cases for Cloud Pub/Sub where the publishers and subscribers are meant to be decoupled, meaning the subscriber inherently doesn't know the message IDs prior to receiving the messages.
You may instead want to transmit the messages via whatever mechanism you are using to making the subscribers aware of the message IDs. Or, if you know at publish time which messages will ultimately need to be retrieved, you could add an attribute to the message to indicate this and use filtering.
currently i have a cloud-build application which is being kicked off by a pub-sub trigger , subscribing to eg. topic1
I would like to know if i can kick off another cloud-build application from subscribing to the same topic. Is there a way to configure the message (or the trigger) so that if message1 is published to topic1, then cloudbuild1 is kicked off, and if message2 is published to topic1, then cloudbuild2 is kicked off?
Kind regards
marco
When you create a subscription on a topic, all the published messages in the topic are replicated in each subscription.
Therefore, if you have TOPIC and Sub1 and Sub2, if you publish 1 message in TOPIC, you will have this message in Sub1 and Sub2.
However, you can set up a filter on messages when you create a subscription. You can set this filter only at the creation and you can't update it later. You need to delete and recreate the subscription if you want to update the filter.
In addition, you can filter only on message attributes, not on the message body content.
Therefore, with filter, think wisely your filter from the beginning and when you publish a message in TOPIC, add attributes that allow your to route the messages to the correct subscription.
I am new to pub/sub on GCP and have some difficulties on understanding some concepts. So if I want to get email every time I have new message in my mailbox, can I use Pub/Sub for that? How the push notification work in that case? I understand the subscriber concepts but I have some difficulties in the publisher concepts. Can anyone help?
Although I am not familiar with the Gmail API (I am specialized mainly in GCP), a quick read over the documentation can provide some really useful insights about this topic. Also, as per your question, I think your doubts are more related to Pub/Sub itself, rather than Gmail API, so let me try to clarify some things for you.
I can see in the Gmail API documentation, that you can configure Gmail to send push notifications using Cloud Pub/Sub topics, in such a way that Gmail sends publish requests to a Pub/Sub topic whenever a mailbox update matches the configuration you established. Although I cannot get into much details about this part of the scenario, from the documentation I understand that the way to configure the Gmail push notifications is to make a watch() request with the configuration you want and pointing a Pub/Sub topic that you should have previously created. Once this is set (and also permissions are correctly configured), Gmail would keep publishing mailbox message updates for a period of 7 days (after a week, you have to re-call watch()).
In order to receive notifications, you can now forget completely about the Gmail API, and you can focus on Pub/Sub. You should create a Pub/Sub subscription (using either Pull or Push configuration, depending on your requirements), so that your client (wherever and whatever it is) receives the Pub/Sub messages that work as a notification. You may have to acknowledge the messages so that they are not retried, too.
As a side note, given that you mentioned that the Pub/Sub subscriber concepts are more or less clear to you, and you would like to know more about publishing, let me share with you some links that may come in handy for a better understanding of the environment:
Pub/Sub main concepts.
Typical Pub/Sub flow.
General guide for Pub/Sub publishers.
In the scenario you are presenting (Gmail notifications using Pub/Sub), you would have to create a topic (with the name you want, let's name it gmail_topic), and the Gmail API would be your publisher. What the watch() method would be doing, behind the scenes, is calling the publish() method to send messages (containing information about mailbox updates) to your topic gmail_topic. Messages are passed to Pub/Sub subscriptions (which you can create and bind to the gmail_topic), and they retained in each of the subscriptions for 7 days (the maximum retention period) until you consume and acknowledge them.
We need to create a monitor that will show any income calls in our extranet in live time.
We were able to show active calls by using /account/~/extension/~/active-calls, however, to achieve what we need we would need to make a request each second which I guess will be blocked by rate limits.
Is there a better solution for it?
Thanks
Subscription (Push Notification) API resource empowers developers to enable the client application(s) to create a single subscription (to one or more extension's) and continually receive push notifications in real time for each subscribed extension.When using this approach for your application(s) to receive events on your RingCentral account, no polling is involved.
You can create a subscription using either of the below-mentioned transportType for receiving push notifications:
PubNub
WebHook
Notifications which the client wants to receive can be specified by the event filters which are set in the subscription request. The event filter is exposed as a URL, pointing to the required RingCentral API resource. Currently the following event types are available for notifications: extensions, messages and presence. They are described in detail below:
Notifications Event Types
You can take a look at the Subscription API below:
Subscription API
If you are interested in Subscribing to Push notifications via WebHook then we have an Easy-to-follow Quickstart guide here:
RingCentral Webhooks Quickstart Guide