Page stuck on environment checking indefinitely when call to get secure mode fails

[ajcasagrande]

Not a big deal, but an observation I made.

🐞 Bug Report

Affected Services [REQUIRED]

edgex-ui

Is this a regression?

Not sure

Description and Minimal Reproduction [REQUIRED]

Run ng serve, but do not run the go binary. Load localhost:4000 (or whatever you serverd it on) and the page will fail to proxy getSecureMode. You will end up with a stuck page spinning the "environment checking" indefinitely.

The UI should probably handle the error case from that call and redirect to an error page.

🔥 Exception or Error

🌍 Your Environment

Deployment Environment:

EdgeX Version [REQUIRED]:

Anything else relevant?

[badboy-huaqiao]

@ajcasagrande yeah, good catch, but that's will never happen in product environment, the development env is different from the deployment environment(or let's call it product environment), the GUI backend server must be running if you want to develop it.

• in development environment, both ng serve and GUI backend server are required
• in product/deployment environment, only GUI backend server is required, developers must build the angular firstly, then move the dist directory to golang static directory

see #467, I'm planning to provide some development guide

but it's also good idea if we provide a error page and redirect to it in development environment, maybe it will be used in deployment environment