Mercure keeps binding to port 80 - mercure

Question

I'm using the Mercure hub 0.13, everything works fine on my development machine, but on my test server the hub keeps on trying to bind on port 80, resulting in a error, as nginx is already running on port 80.
run: loading initial config: loading new config: http app module: start: tcp: listening on :80: listen tcp :80: bind: address already in use
I'm starting the hub with the following command:
MERCURE_PUBLISHER_JWT_KEY=$(cat publisher.key.pub) \
MERCURE_PUBLISHER_JWT_ALG=RS256 \
MERCURE_SUBSCRIBER_JWT_KEY=$(cat publisher.key.pub) \
MERCURE_SUBSCRIBER_JWT_ALG=RS256 \
./mercure run -config Caddyfile.dev
Caddyfile.dev is as follows:
# Learn how to configure the Mercure.rocks Hub on https://mercure.rocks/docs/hub/config
{
{$GLOBAL_OPTIONS}
}
{$SERVER_NAME:localhost:3000}
log
route {
redir / /.well-known/mercure/ui/
encode zstd gzip
mercure {
# Transport to use (default to Bolt)
transport_url {$MERCURE_TRANSPORT_URL:bolt://mercure.db}
# Publisher JWT key
publisher_jwt {env.MERCURE_PUBLISHER_JWT_KEY} {env.MERCURE_PUBLISHER_JWT_ALG}
# Subscriber JWT key
subscriber_jwt {env.MERCURE_SUBSCRIBER_JWT_KEY} {env.MERCURE_SUBSCRIBER_JWT_ALG}
# Permissive configuration for the development environment
cors_origins *
publish_origins *
demo
anonymous
subscriptions
# Extra directives
{$MERCURE_EXTRA_DIRECTIVES}
}
respond /healthz 200
respond "Not Found" 404
}
When I provider the SERVER_NAME as an environment variable, without a domain, SERVER_NAME=:3000, the hub actually starts on port 3000, but runs in http mode, which only allows for anonymous subscriptions and is not what I need.
Server:
Operating System: CentOS Stream 8
Kernel: Linux 4.18.0-383.el8.x86_64
Architecture: x86-64
Full output when trying to start the Mercure hub:
2022/05/10 04:50:29.605 INFO using provided configuration {"config_file": "Caddyfile.dev", "config_adapter": ""}
2022/05/10 04:50:29.606 WARN input is not formatted with 'caddy fmt' {"adapter": "caddyfile", "file": "Caddyfile.dev", "line": 3}
2022/05/10 04:50:29.609 INFO admin admin endpoint started {"address": "tcp/localhost:2019", "enforce_origin": false, "origins": ["localhost:2019", "[::1]:2019", "127.0.0.1:2019"]}
2022/05/10 04:50:29.610 INFO http enabling automatic HTTP->HTTPS redirects {"server_name": "srv0"}
2022/05/10 04:50:29.610 INFO tls.cache.maintenance started background certificate maintenance {"cache": "0xc0003d6150"}
2022/05/10 04:50:29.627 INFO tls cleaning storage unit {"description": "FileStorage:/root/.local/share/caddy"}
2022/05/10 04:50:29.628 INFO tls finished cleaning storage units
2022/05/10 04:50:29.642 INFO pki.ca.local root certificate is already trusted by system {"path": "storage:pki/authorities/local/root.crt"}
2022/05/10 04:50:29.643 INFO tls.cache.maintenance stopped background certificate maintenance {"cache": "0xc0003d6150"}
run: loading initial config: loading new config: http app module: start: tcp: listening on :80: listen tcp :80: bind: address already in use

Answer 1

I'm a bit late, but I hope that will help someone.
As mentionned here, you can specify the http_port manually in your caddy configuration file.