Logstash+Kibana config flexibility improvements

[PMazarovich]

Motivation and context

It is important to be able to connect to remote instances of Logstash or Kibana. With this changes you can simply configure any address (with or without credentials) via environment variables.
As example you can use this with AWS: for Logstash you can use Fargate, for the rest - Amazon Elasticsearch, which provide access to Kibana by URL.

How has this been tested?

It was tested manually.

Checklist

• [ x] I submit my changes into the develop branch

# Copyright (C) 2020 Intel Corporation
#
# SPDX-License-Identifier: MIT

[azhavoro]

@PMazarovich, thanks for the your contribution!

[azhavoro]

If the cvat_proxy service does not use the default CVAT_HOST or port, then Kibana will not be available at http://localhost:8080/analytics/app/kibana, so this setting must be changed consistently. From my point of view, this is not good.
Inside the cvat backend uses a reverse proxy for proxy requests in kibana, I would suggest making this django app customizable and pass CVAT_KIBANA_URL env variable into cvat instead of the current implementation. Do you see any problems with this approach?

[PMazarovich]

We do not use "default" cvat_proxy service (also cvat_logstash, cvat_elasticsearch and cvat_kibana), instead all these services from AWS or using Fargate, and accessed via Application Load Balancer. So it is necessary for us to have this cvat_kibana_url inside cvat_ui container, not in cvat one.
Or did I misunderstand something and there is some additional reverse proxy logic there?

[azhavoro]

@PMazarovich sorry for the late response
I mean your changes breaks the current approach to setting the cvat hostname with a single env variable (CVAT_HOST). For example, if I want to use anything other than localhost as the cvat hostname with the default ELK, with your changes, I have to set 2 environment variables accordingly: CVAT_HOST and CVAT_KIBANA_URL.
I just would suggest proxy all requests to kibana independently of kibana URL as it's implemented now.
Also one more issue: regardless on CVAT_KIBANA_URL setting UI displays the Analytics tab as origin URL

[PMazarovich]

In our case it is impossible to leave only CVAT_HOST variable because AWS kibana is accessible through this path: /_plugin/kibana/, not this one: /analytics/app/kibana. That is why I suggest to leave approach from the PR. Of course, you can change this in header.tsx, but, as for me, it is better to create another ENV rather than changing code. As for your notice about href, I'll perform another commit this week, that solves the problem.

[bsekachev]

Agree with Andrey, proposed changes look complicated. IMHO a client should work only with its server and if analytics located somewhere else, the server is expected to proxy request where need. Other approaches over complicate the architecture and configuration.

[PMazarovich]

Changes with corrections are performed taking into account the wishes of developers and minimized in general.

[coveralls]

Coverage remained the same at 70.28% when pulling c73400e on PMazarovich:Logstash_Kibana_config_fix into c62949b on openvinotoolkit:develop.

[azhavoro]

@PMazarovich LGTM, could you please add a note to changelog.md about this change? Thanks!

[PMazarovich]

Changelog updated.