Envision multi-instance display

[Adaickalavan]

BUG REPORT

Unable to view multi-instance display when "All Simulations" is selected in Envision while running multiple SMARTS instances.

SMARTS version
0.4.15

Previous associated issues
None

Steps to reproduce the bug

1. Start envision in a terminal

   $ scl envision start -s ./scenarios -p 8081
   

2. Start SMARTS simulation in another terminal

   $ python3.7 ./examples/multi_agent.py ./scenarios/intersections/6lane/
   

Resulting and expected behaviour
Expected: Able too see multi-instance display in Envision when "All Simulations" options is selected.

Error logs and screenshots
None

System information- Operating system & Environment [Please note if using Docker]: Ubuntu 16.04

• Number of system cores available: 16
• Python version [Please note if using Jupyter]: Python3.7
• Python packages [e.g. from pip freeze]
• SUMO version: 1.8.0
• Date when bug occurred: 19 April 2021

Impact [If known]
Unable to view multi-instance display in Envision.

[RutvikGupta]

Something related to this was addressed in PR #363. But that was fixed before this issue was noticed.

[RutvikGupta]

After tracking down, the git commit history, it seems like the multi-instance display stopped working after SMARTS version 0.4.14 release. c847304

[RutvikGupta]

After some more investigation, its safe to say that the issue is arising from changes done to the .js files in this release. Changes to the client.py or other .py in envision don't seem to be the issue.

[RutvikGupta]

PR #585 and #580 made changes to the JavaScript files after SMARTS version 0.4.13 release and before SMARTS version 0.4.14 release which caused the multi-instance display to stop working. The multi-instance display is not working for both of these PRs but was before them.

[RutvikGupta]

Actually PR #580 is the cause of this issue since PR #585 was rebased on that and checking PR #585 separately shows that it didn't break the multi-instance.

[RutvikGupta]

Also for PR #545, the following code snippet in app.js tries to reconnect to a single simulation every time you switch to "All Simulations" not allowing you to stay at the multi-instance page.

Removing it fixes that issue for that PR.

[RutvikGupta]

Ok, so I found the bug. Will open a PR soon.