[GitHub] [pulsar] cdbartholomew opened a new issue #5415: Dashboard doesn't work in pulsar-standalone docker image

[GitBox <gi...@apache.org>]

cdbartholomew opened a new issue #5415: Dashboard doesn't work in pulsar-standalone docker image
URL: https://github.com/apache/pulsar/issues/5415
 
 
   **Describe the bug**
   If you run the pulsar-standalone docker image, which bundles the dashboard with pulsar, the dashboard collecter fails to run, with this error:
   
   ```
   Traceback (most recent call last):
     File "./collector.py", line 58, in fetch_broker_stats
       _fetch_broker_stats(cluster, broker_url, timestamp)
     File "./collector.py", line 76, in _fetch_broker_stats
       topics_stats = get(broker_url, '/admin/v2/broker-stats/destinations')
     File "./collector.py", line 41, in get
       proxies=http_proxyes,
     File "/usr/local/lib/python2.7/dist-packages/requests/models.py", line 897, in json
       return complexjson.loads(self.text, **kwargs)
     File "/usr/lib/python2.7/json/__init__.py", line 339, in loads
       return _default_decoder.decode(s)
     File "/usr/lib/python2.7/json/decoder.py", line 364, in decode
       obj, end = self.raw_decode(s, idx=_w(s, 0).end())
     File "/usr/lib/python2.7/json/decoder.py", line 382, in raw_decode
       raise ValueError("No JSON object could be decoded")
   ValueError: No JSON object could be decoded
   ```
   
   The issue is that the endpoint `/admin/v2/broker-stats/destinations` doesn't exist. In the V2 API, the endpoint was renamed to `/admin/v2/broker-stats/topics`. The fix is a simple replacement of "destinations" with "topics" in `collector.py`.
   
   While investigating this, I noticed this change was made in PR #3657, which made its way into the Docker image in 2.4.0:
   ```
   workspace ~/pulsar/docker $ docker run -it apachepulsar/pulsar-standalone:2.3.1 grep destinations /pulsar/django/collector.py
       topics_stats = get(broker_url, '/admin/broker-stats/destinations')
   workspace ~/pulsar/docker $ docker run -it apachepulsar/pulsar-standalone:2.4.0 grep destinations /pulsar/django/collector.py
       topics_stats = get(broker_url, '/admin/v2/broker-stats/destinations')
   ```
   I was wondering why the Pulsar dashboard works for anyone after this change was made. I was baffled for a while, until I realized the repo has 2 copies of `collector.py`, which, believe me, is confusing. 
   
   The main dashboard image is built from the files in `dashboard/django`. The `collector.py` in that directory was not modified by PR #3657. So, the main dashboard Docker image is fine.
   
   However, for building the pulsar-standalone Docker image, the `docker/pulsar-standalone/django` directory is used. That file was modified (incorrectly) in #3657. There really should be a single source for the these Django files.
   
   I think it would be possible to modify the pulsar-standalone Dockerfile to use the main `dashboard/django` files when building the pulsar-standalone Docker image. Then the changes made in the two copies of `collector.py` can be merged into a single file.
   
   I will put together a PR with changes to this effect.
   
   **To Reproduce**
   
   You just need to run the pulsar-standalone Docker image. This is how I do it:
   
   ```
   docker run \
   	-p 6650:6650 -p 8081:8080 -p 80:80\
   	-d --rm \
   	--name pulsar-standalone  \
   	--mount source=pulsardata,target=/pulsar/data \
           --mount source=pulsarconf,target=/pulsar/conf \
   	apachepulsar/pulsar-standalone:2.4.1 
   ```
   
   **Expected behavior**
   The dashboard should work in this Docker image, since that seems to be the point of it. It is essentially pulsar-all image plus the dashboard.
   
   

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