These are chat archives for allegro/hermes

24th
Apr 2018
DeveloperFMS
@DeveloperFMS
Apr 24 10:44

Hello there,
I have a few questions regarding the configuration of Hermes. I hope you can help me with those. I will ask one question at a time.

The hermes-console-config.json file provided in the folder vagrant_provisioning\conf has under the "metrics" node the "prefix" value set to "hermes". Shouldn't it be set to "stats.tech.hermes" as this is the default prefix set for the frontend and the consumer ?

DeveloperFMS
@DeveloperFMS
Apr 24 13:05
Question2: It is not clear in the documentation what needs to be setup to be able to have the list of the last 100 discarded messages.
It is stated under "http://hermes-pubsub.readthedocs.io/en/latest/user/subscribing/" that "with message tracking enabled, it is also possible to list last 100 undelivered messages" but it is also stated under "http://hermes-pubsub.readthedocs.io/en/latest/configuration/message-tracking/" that for message-tracking a message-tracking store has to be implemented/installed (such as ElasticSearch).
Does this mean that a pre-requisite to enable message-tracking is to install the message-tracking store ? If we install the message-tracking store and enable the message-tracking under subscription will we be able to see the last 100 discarded messages ?
Question3: Does the same apply to the message flow information?
Question4: In all the "metrics" panels in the console, some properties are shown with ":" and others not. Examples are, in the Subscription metrics, "Delivery rate:" and in the Service response metrics, "2xx".
Do we understand correctly that the hyperlinks without the ":" are only link to the Graphite graphics and we should not expect a basic figure in the console and that the others are both link to the Graphite graph AND basic figure are expected in the console (as long as Management module is connected correctly to Graphite via the HTTP API)?
DeveloperFMS
@DeveloperFMS
Apr 24 13:10
Question5: Basic counters and other basic metrics: It is not clear which figures is linked to which metric store.
In the PDF "https://media.readthedocs.org/pdf/hermes-pubsub/latest/hermes-pubsub.pdf" p27 "Metrics" one could read:
  • metrics.zookeeper.reporter -> "should we report counter metrics to Zookeeper"
  • metrics.graphite.reporter -> "should we send all metrics to Graphite"
    What is the link to the metrics shown in the console?
    For example we could see that indicators "Delivered", "Discarded" in the Subscription metrics and "Published" in the topic metrics seem to be linked to "metrics.zookeeper.reporter" whereas the other indicators are linked to "metrics.graphite.reporter". Is this correct ?
Question6: What could be the first reasons that come to your mind having the metric “Delivered” and “Discarded” staying at 0 even if the messages are consumed by the endpoint ?
Question7: How could we setup Hermes to not retry to send a message to an endpoint when the response is a 5xx type error and set it directly to discarded ? (basically the same way Hermes react to the 404 error when Retry on 4xx status is set to false)
These are all my questions for now. Thank you in advance