Reliable way to tell whether server is running

[king-of-poppk]

Currently, the startup message "Running plumber API at ..." is printed before this line is reached:

plumber/R/plumber.R

Line 279 in dcf7692

httpuv::runServer(host, port, self)

which makes it difficult to time when the server is actually started (think tests).

One way to fix this is to print that message (and possibly also "Running swagger Docs at ..."), or something else, between httpuv::startServer and httpuv::service here, by using those directly instead of relying on the httpuv::runServer abstraction.

[ElianHugh]

FWIW, a workaround is to have a dummy endpoint and ping it using httr2/whatever and return FALSE on error

I use this pattern in my autoreloader to check if the api is up

https://github.com/ElianHugh/hotwater/blob/main/R/middleware.R#L85-L105

[schloerke]

I believe the messages could be printed in a later::later(function() { message("SERVER STARTED") }, delay = 0). This would delay the message until the R process releases control back to {later} processing loop.