Symfony 6 - Mercure - DDEV sandbox

Setup

• Have DDEV 1.22.0
• Run ddev start
• Run ddev composer install
• You now have a running Symfony 6.3 with a Mercure hub on HTTPS port 10002

Operation

• Visit https://sandbox-sf6.ddev.site/ in your modern browser
• Open your inspection window to check the console; this will show you any connection errors in more detail
• When connection to your local Mercure publisher hub works, then you should not see an error
• When no error, run ddev php bin/console app:mercure:run on your command line; this will start a command that will push an update every second
• Watch your browser where a block should appear that changes color every second (i.e. with every update)
• When there is an error, it may be a CORS error in your network tab, but this is generic because the response did not provide a correct header structure - visit https://sandbox-sf6.ddev.site:10002/.well-known/mercure?topic=whatever to see the real problem: a 502 Bad Request

DDEV config: the difference between error or not

The following DDEV global config works (i.e. with deprecated nginx-proxy router):

Global configuration: 
instrumentation-opt-in=true 
omit-containers=[] 
web-environment=[] 
performance-mode=none 
router-bind-all-interfaces=false 
internet-detection-timeout-ms=3000 
disable-http2=false 
use-letsencrypt=false 
letsencrypt-email= 
table-style=default 
simple-formatting=false 
auto-restart-containers=false 
use-hardened-images=false 
fail-on-hook-fail=false 
required-docker-compose-version=v2.20.0 
use-docker-compose-from-path=false 
project-tld= 
xdebug-ide-location= 
no-bind-mounts=false 
router=nginx-proxy 
wsl2-no-windows-hosts-mgt=false 
router-http-port=80 
router-https-port=443 

The following DDEV global config does not work - the only change here is using the now default traefik router:

Global configuration: 
instrumentation-opt-in=true 
omit-containers=[] 
web-environment=[] 
performance-mode=none 
router-bind-all-interfaces=false 
internet-detection-timeout-ms=3000 
disable-http2=false 
use-letsencrypt=false 
letsencrypt-email= 
table-style=default 
simple-formatting=false 
auto-restart-containers=false 
use-hardened-images=false 
fail-on-hook-fail=false 
required-docker-compose-version=v2.20.0 
use-docker-compose-from-path=false 
project-tld= 
xdebug-ide-location= 
no-bind-mounts=false 
router=traefik 
wsl2-no-windows-hosts-mgt=false 
router-http-port=80 
router-https-port=443 

Remember to ddev poweroff && ddev restart between config changes to minimize any corruption of config changes. And, of course, to have them in effect...