Docs: how to run/test the UI

[esnible]

Attempting to follow the directions at https://github.com/jaegertracing/jaeger-ui#development by doing yarn start brings up a screen that says Unhandled Rejection (Error): HTTP Error: Error occured while trying to proxy to: localhost:3000/api/services.

I have another Jaeger running at 16686, but the instructions don't explain how to point the yarn start version at :3000.

The way I have been testing UI changes is:

• Make the changes in the jaegar/jaeger-ui submodule
• yarn build (from the jaeger-ui submodule directory)
• make run-all-in-one (from the jaeger directory)
• hard-reload the browser

I am happy to make a PR to change the doc to my method. If there is a better way to make the yarn start UI talk to :16686 that would be better than doing a build for each change.

[yurishkuro]

I am not sure what specific issue you're running into. My understanding is that yarn start runs a web server on port 3000 that serves UI assets (with hot reloading support), but the API requests are being proxied to the standard port :16686 where Jaeger is expected to be running.

I just tried it, run $ go run ./cmd/all-in-one in jaeger/ and then yarn start in jaeger-ui/

[esnible]

Ah, thanks for checking. I was able to duplicate your process. You are correct; there is no problem with the UI.

I run Jaeger using

ADMIN_HTTP_HOST_PORT=localhost:14269 HTTP_SERVER_HOST_PORT=localhost:5778 \
COLLECTOR_GRPC_SERVER_HOST_PORT=localhost:14250 COLLECTOR_HTTP_SERVER_HOST_PORT=localhost:14268 \
QUERY_HTTP_SERVER_HOST_PORT=localhost:16686 QUERY_GRPC_SERVER_HOST_PORT=localhost:16685 \
PROCESSOR_JAEGER_BINARY_SERVER_HOST_PORT=localhost:6832 \
make run-all-in-one

I do that because, on a Mac, Jaeger's defaults lead to many "Do you want the application 'all-in-one' to accept incoming network connections?" dialogs popping up. Having the server listen on localhost instead of 0.0.0.0 eliminates those dialogs -- but is not compatible with the proxying done by yarn start.

Using QUERY_HTTP_SERVER_HOST_PORT=0.0.0.0:16686 or merely using the default allows yarn start to work correctly.

I found this surprising. I tried to investigate, and found packages/jaeger-ui/src/setupProxy.js. I'm not a yarn guy. I couldn't figure out why listening on 127.0.0.1 is OK with curl localhost:16686 but not with yarn's proxying.

[esnible]

Closing because I have a report that this work correctly on Linux. It isn't clear what the Mac problem is, or if every Mac user experiences it. The work-around of not overriding the QUERY_HTTP_SERVER_HOST_PORT flag when testing is sufficient.