here is my docker compose. change env as needed. I used mongo express.

unifi:
image: lscr.io/linuxserver/unifi-network-application:latest
container_name: unifi
depends_on:
- mongo
#- mongo-express
environment:
- PUID=1000
- PGID=1000
- TZ=Etc/UTC
- MONGO_USER=${POSTGRES_USER}
- MONGO_PASS=${POSTGRES_PASSWORD}
- MONGO_HOST=mongo
- MONGO_PORT=27017
- MONGO_DBNAME=unifi
- MEM_LIMIT=1024 #optional
- MEM_STARTUP=1024 #optional
volumes:
- /docker/unifi/data:/config
ports:
- 8443:8443
- 3478:3478/udp
- 10001:10001/udp
- 8080:8080
- 1900:1900/udp #optional
- 8843:8843 #optional
- 8880:8880 #optional
- 6789:6789 #optional
- 5514:5514/udp #optional
restart: unless-stopped
##############################################################
mongo:
container_name: mongo
image: mongo
restart: unless-stopped
#environment:
#- MONGO_INITDB_ROOT_USERNAME:${POSTGRES_USER}
#- MONGO_INITDB_ROOT_PASSWORD:${POSTGRES_PASSWORD}
volumes:
- /docker/mongo/data:/data/db
- /docker/mongo/init-mongo.js:/docker-entrypoint-initdb.d/init-mongo.js:ro