list_subscriptions does not work properly

[bitcpf]

list_subscriptions() works but list_subscriptions(topic_name = 'topic_name') does not work properly

>>> from gcloud import pubsub
>>> client = pubsub.Client(project = 'my_project')
>>> client.list_subscriptions(topic_name = 'my_topic')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/gcloud/pubsub/client.py", line 131, in list_subscriptions
    for resource in resp['subscriptions']]
  File "/usr/local/lib/python2.7/dist-packages/gcloud/pubsub/subscription.py", line 68, in from_api_repr
    topic_path = resource['topic']
TypeError: string indices must be integers

[tseaver]

ATM, topic_name is the third positional argument: you need to call it as a named parameter:

client.list_subscriptions(topic_name='topic_name')

@jgeewax, @dhermes I'm reading this issue as a request to make topic_name the first positional argument. Opinions?

[dhermes]

👍

[bitcpf]

@tseaver
Sorry, what I really want to say is I wrote the command as:

subscription, next_page_tokens = client.list_subscriptions(topic_name = 'topic_name')

It does not work. And the issue is this line:

        subscriptions = [Subscription.from_api_repr(resource, self,
                                                    topics=topics)
                         for resource in resp.get('subscriptions', ())]

The code pass an empty value of resource (maybe) to subscriptions.

The output is like:

>>> from gcloud import pubsub
>>> client = pubsub.Client(project = 'my_project'')
>>> client.list_subscriptions(topic_name = 'my_topic')
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python2.7/dist-packages/gcloud/pubsub/client.py", line 131, in list_subscriptions
    for resource in resp['subscriptions']]
  File "/usr/local/lib/python2.7/dist-packages/gcloud/pubsub/subscription.py", line 68, in from_api_repr
    topic_path = resource['topic']
TypeError: string indices must be integers

[dhermes]

@tseaver Have you reproduced?

[dhermes]

@tseaver I reproduced:

>>> import gcloud.pubsub
>>> from gcloud import _helpers
>>> from gcloud.environment_vars import TESTS_PROJECT
>>> _helpers.PROJECT = TESTS_PROJECT
>>> C = gcloud.pubsub.Client()
>>> C.project
'FOOOBAR'
>>> C.list_subscriptions()
([], None)
>>> C.list_topics()
([], None)
>>> T = C.topic('hi-mom')
>>> T.create()
>>> S = T.subscription('this-is-mine')
>>> S.create()
>>> C.list_topics()
([<gcloud.pubsub.topic.Topic object at 0x7f7c21812310>], None)
>>> C.list_subscriptions()
([<gcloud.pubsub.subscription.Subscription object at 0x7f7c21812390>], None)
>>> C.list_subscriptions(topic_name=T.name)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "gcloud/pubsub/client.py", line 131, in list_subscriptions
    for resource in resp.get('subscriptions', ())]
  File "gcloud/pubsub/subscription.py", line 71, in from_api_repr
    topic_path = resource['topic']
TypeError: string indices must be integers

[dhermes]

In [16]: %debug
> .../gcloud-python/gcloud/pubsub/subscription.py(71)from_api_repr()
     69         if topics is None:
     70             topics = {}
---> 71         topic_path = resource['topic']
     72         topic = topics.get(topic_path)
     73         if topic is None:

ipdb> resource
u'projects/omega-moonlight-697/subscriptions/this-is-mine'
ipdb> u
> .../gcloud-python/gcloud/pubsub/client.py(131)list_subscriptions()
    129         subscriptions = [Subscription.from_api_repr(resource, self,
    130                                                     topics=topics)
--> 131                          for resource in resp.get('subscriptions', ())]
    132         return subscriptions, resp.get('nextPageToken')
    133 

ipdb> resp
{u'subscriptions': [u'projects/omega-moonlight-697/subscriptions/this-is-mine']}

[dhermes]

This is in contrast to what the output looks like without the topic name:

{
  "subscriptions": [
    {
      "topic": "projects/omega-moonlight-697/topics/hi-mom", 
      "ackDeadlineSeconds": 10, 
      "pushConfig": {}, 
      "name": "projects/omega-moonlight-697/subscriptions/this-is-mine"
    }
  ]
}

[tseaver]

OK, I see the issue: projects.subscriptions/list'](https://cloud.google.com/pubsub/reference/rest/v1/projects.subscriptions/list) is documented to return the full Subscriptions resource, whereas [projects.topics.subscriptions/list` is documented to return only a list of subscription URLs.

The API design choice here is utterly bogus, but we have to work around it.

[tseaver]

Given the disparity, I would prefer to handle topic-based subscriptions by adding a list_subscriptions method to the Topic class.

[tseaver]

@bitcpf Thanks for the report!

[dhermes]

👍 with separate methods @tseaver

[tseaver]

@dhermes see #1580 for the implementation.