Adding the ability to set Subscription path

[philibuster]

A user should be able to set the path of the subscription, so it isn't always set to the topics project.

This allow users to subscribe to topics in other projects (if they have edit rights to said project).

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[dhermes]

@philibuster Can you give some sample code using this or some description of why you'd want to be able to change the project on the fly.

This change is a little too ad-hoc for the object model, but that doesn't mean we can't take the spirit of the change and turn it into something useful.

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A subscription has 4 properties

name
topic
ack_deadline
push_endpoint

and you could accomplish essentially what you want with

topic1 = Topic(name, project=project1)
topic2 = Topic(name, project=project2)

subscription1 = Subscription(sub_name, topic1, ack_deadline=AD, push_endpoint=PE)
subscription2 = Subscription(sub_name, topic2, ack_deadline=AD, push_endpoint=PE)

but it could be more convenient to have something which preserved all properties except for the topic via:

subscription2 = Subscription.copy_from(subscription1, topic=topic2)

Even more, you want the same topic name, but just a different project, so this still isn't quite the same.

[philibuster]

Thank you for the response. Sorry I made a mistake in my code, what I originally wrote would have no value.

Example:
There are two projects:

1. project1 with one topic "topic1"
2. project2 with no topics (it doesnt matter)

As project2 I want to make a subscription to the other projects topic.
If I made a subscription it will try use the first project. projects/project1/subscriptions/sub with project/project1/topics/topic1
But I want projects/project2/subscriptions/sub with project/project1/topics/topic1

What I am proposing is using any project in the subscription path. It still will only work if they are allowed access to create the subscription anyway.

[dhermes]

I see. So my proposal would need to be tweaked to something like

>>> topic = Topic(name, project=project1)
>>> subscription = Subscription(sub_name, topic, ack_deadline=AD, push_endpoint=PE)
>>> # New code
>>> subscription2 = Subscription.copy_from(subscription1, project=project2)
>>> subscription.topic.name == subscription2.topic.name
True
>>> subscription.topic is subscription2.topic
False
>>> subscription.topic.project == subscription2.topic.project
False

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PS @philibuster Sorry for getting behind on this.

[philibuster]

@dhermes No problem :)

Not exactly, the topic should not be changed, just the subscription path

>>> subscription.topic == subscription2.topic
True
>>> subscription.path == subscription2.path
False

[dhermes]

@philibuster That breaks the model, which is why I was offering the alternative.

As of right now (June 18), the hierarchy is

client -> topic -> subscription

and a client has a fixed project, which both the topic and subscription can reference and use.

[dhermes]

@philibuster WDYT of the proposed given my comment?

I want to keep this moving (either to close it out or to get to something we can agree on implementing).

[dhermes]

@philibuster I'd love to take this up, let's re-open if you get some bandwidth to keep the discussion moving forward.

[philibuster]

@dhermes Sorry about the delay.

Yeah all for a copy_from method, maybe similar to modify_push_configuration. I think it'd be a useful method (at least to me and those that work with me), as it'd allow subscribing to other projects topics.