Derived Telemetry Prototype

[scottbell]

Is your feature request related to a problem? Please describe.
Create a new objected in Open MCT that supports a user entered expression (in math.js format) and outputs the result of that expression as telemetry.

[charlesh88]

In progress notes while working in the branch. This may totally just be stuff you haven't gotten to yet, but if not, you're welcome:

• An output of 0 is being rendered as "---".
  • Exp a with test value 0 would expect to output 0.
  • Exp a*b with test values of 0 and 1 respectively would expect to output 0.
  • Exp a+b with -10 and 10 would expect to output 0.
• When exiting edit mode with "Apply Test Values" enabled, the subsequent browse view works as if test values are being applied - but it should not. Test values should only be applied while in edit mode. Refreshing or navving away and back resets the view with test values apparently disabled. We should immediately update the output field on exiting edit mode to the default value "---" and then allow it to naturally be updated by any live telemetry values if we have them.

[charlesh88]

Changes so far:

• New component /ui/components/ObjectPathString.vue used instead of ObjectPath.
• New CSS defs in comps.scss.
• Layout, styling cleanups.
• Test values section of telemetry ref elements now hidden when not in edit mode.
• Tweaks to messaging.
• Removed error icon applied to main holder.
• Refined resize behavior of expression entry textarea.

[charlesh88]

Todos

@charlesh88

• Continue style refinements, particularly code validation / error message area.
• Refine main 'output' field at top of UI to better handle long values, like arrays.

[scottbell]

Great work @charlesh88! I think I addressed the issues you described, and am working toward some e2e tests now. One question though: do we want to make the expression itself more prominent? It's rather small now, and is probably the main thing I want to be looking at when I bring up the view?

[charlesh88]

Agree on the smallness of the expression; gave it a monospace font which looks bigger and is just better. Have pushed what I think are near complete changes for derived telemetry:

• Final sanding and polishing.
• New discrete item style c-output-featured added to controls.scss.
  • Applied to 'Current Output' section of both Derived Telemetry and Condition Sets.
• Added icons and styling to expression validation message. Message now shows in browse mode if invalid.
• Monospace font used in expression input and browse mode display.

TODOs:

• Check for low-risk regressions in Condition Sets browse and edit modes.
• New tests for ObjectPathString.vue component.

[scottbell]

To test:

1. Create a new Derived Telemetry object
2. Drop a couple of SWGs on it
3. Change the parameter names from a to x, and b to y
4. Add a simple math.js expression: x*y - ensure expression is valid
5. Change expression to a*b - ensure expression is marked invalid
6. Change back to a*b, and add some test values to the parameters (e.g., 2 and 5), then toggle "Apply Test Data". Ensure the output matches the multiplication.
7. Go to the inspector tab in edit mode, and change the output format to %0.2f and save. Ensure floating point is formatted to only two decimals places in the output.
8. Untoggle "Apply Test Data" and put time conductor in real time mode. Ensure "Current Output" has a changing number that looks reasonable.
9. Drop Derived telemetry into an overlay plot along with the SWGs. Ensure both historical and realtime data plots.

[unlikelyzero]

Needs developer review but the tests and a11y look great. I made some comments.

Also we need to create good release notes and be sure to call this experimental. I went ahead and moved this to the 4.1.0 release