matrix: can't nest variable substitution

matrix/README.md

@@ -17,6 +17,7 @@ echo SYNAPSE_SMTP_PORT=465 >> .env
 echo SYNAPSE_SMTP_HOST=mail.gandi.net >> .env
 echo SYNAPSE_SMTP_USER=dev@oxyta.net >> .env
 echo SYNAPSE_SMTP_PASSWORD=changeme >> .env
+echo SYNAPSE_SERVER_NAME=matrix.localhost >> .env
 ```
 
 ## Deploy

matrix/docker-compose.yml

@@ -11,7 +11,7 @@ services:
     env_file:
       - .env
     environment:
-      - SYNAPSE_SERVER_NAME=${SYNAPSE_SERVER_NAME:-${CHATONS_SERVICE:-matrix}.${CHATONS_DOMAIN:-localhost}}
+      - SYNAPSE_SERVER_NAME=${SYNAPSE_SERVER_NAME}
     labels:
       traefik.enable: "true"
       traefik.frontend.rule: "Host: ${CHATONS_SERVICE:-matrix}.${CHATONS_DOMAIN:-localhost}, www.${CHATONS_SERVICE:-matrix}.${CHATONS_DOMAIN:-localhost}"
@@ -38,7 +38,7 @@ services:
     build:
       context: .
       args:
-        SYNAPSE_SERVER_NAME: ${SYNAPSE_SERVER_NAME:-${CHATONS_SERVICE:-matrix}.${CHATONS_DOMAIN:-localhost}}
+        SYNAPSE_SERVER_NAME: ${SYNAPSE_SERVER_NAME}
         RIOT_VERSION: v0.17.8
     labels:
       traefik.enable: "true"

proxy

@@ -1 +1 @@
-Subproject commit 99edac5256137764a5b3a0530699eb436438a0d8
+Subproject commit 5d0146cf6960e5f3bd3590a67cf26d2efefc100a