Enhancement request for a 'function' flow activity

[opendevpmm]

I'm submitting a ... (check one with "x")

[] bug report => search github for a similar issue or PR before submitting
[X] feature request
[] support request
[] general question

Current behavior (how does the issue manifest): A user can only use existing functionality from triggers and activities, which limits the possibilities of what can be programmed.

Expected behavior: Competitor tools like Node-red have a 'function' node, where any Javascript code can be written, which makes the tool very flexible and powerful. It would be useful to have such an activity in Flogo, that can take Go code. If it's possible to have C or Javascript, that would be even more powerful, but at a minimum, Go support would be quite useful. And for the IoT device usecase, C may be useful.

Minimal steps to reproduce the problem (not required if feature enhancement): Functionality does not exist, no need to reproduce.

What is the motivation / use case for changing the behavior? Competitors have this functionality, and having it makes the tool very flexible and powerful.

Please tell us about your environment (Operating system, docker version, browser & web ui version, etc): MacOS X version 10.13.5 Docker version 18.03.1-ce, build 9ee9f40 Browser: Firefox Quantum 61.0

Flogo version (CLI & contrib/lib. If unknown, leave empty or state unknown): 0.X.X Flogo version 0.5.3

Additional information you deem important (e.g. issue happens only occasionally): n/a

[mellistibco]

@vijaynalawade has created an activity that can be used to execute JS: https://github.com/vijaynalawade/flogo/tree/master/activity/js