Add _FILE environment variable loading

payload/Dockerfile

@@ -26,4 +26,6 @@ COPY --from=build /build/tsconfig.json ./tsconfig.json
 COPY --from=build /build/dist ./dist
 COPY --from=build /build/build ./build
 EXPOSE 3000
-CMD ["yarn", "serve"]
+COPY docker-entrypoint.sh /docker-entrypoint.sh
+ENTRYPOINT ["/docker-entrypoint.sh"]
+CMD ["yarn", "serve"]

payload/docker-entrypoint.sh

@@ -0,0 +1,32 @@
+#!/bin/bash
+
+set -eu
+
+file_env() {
+  local var="$1"
+  local fileVar="${var}_FILE"
+  local def="${2:-}"
+
+  if [ "${!var:-}" ] && [ "${!fileVar:-}" ]; then
+    echo >&2 "error: both $var and $fileVar are set (but are exclusive)"
+    exit 1
+  fi
+
+  local val="$def"
+  if [ "${!var:-}" ]; then
+    val="${!var}"
+  elif [ "${!fileVar:-}" ]; then
+    val="$(< "${!fileVar}")"
+  fi
+
+  export "$var"="$val"
+  unset "$fileVar"
+}
+
+file_env "TOKEN"
+file_env "MONGODB_PASSWORD"
+file_env "PAYLOAD_SECRET"
+
+export MONGODB_URI="mongodb://$MONGODB_USER:$MONGODB_PASSWORD@$MONGODB_HOST:$MONGODB_PORT"
+
+"$@"