Docker-Compose Unable to connect to any of the specified MySQL hosts - mysql

Question

i have an existing Project ( API - portal - Mysql )
i have used Docker-compose without dockerfile
i publish the API - Portal and put them all in folder and then Docker-compose up
i can reach the api by getting the local values in it
but if i tried to reach mysql trough the API using postman its not working even when i open the frontend website
ConnectionString:
"ConnectionString": "server=xmysql;port=4406;Database=sbs_hani;User ID=hani;Password=123456; persistsecurityinfo=True;Charset=utf8; TreatTinyAsBoolean=false;"
This is my docker-compose file :
version: '3'
services:
xmysql:
container_name: xmysql
hostname: xmysql
image: mysql:latest
restart: always
environment:
MYSQL_ROOT_PASSWORD: "123456"
MYSQL_DATABASE: "sbs_hani"
MYSQL_USER: "hani"
MYSQL_PASSWORD: "123456"
ports:
- "3306:4406"
networks:
- xnetwork
volumes:
- data-volume:/var/lib/mysql
- ./hanimysql/sbs_hani.sql:/docker-entrypoint-initdb.d/sbs_hani.sql
xapi:
container_name: xapi
hostname: xapi
image: microsoft/dotnet:latest
# restart: always
tty: true
command: ["dotnet", "/var/lib/volhaniapi/hani.APIs.dll"]
ports:
- "8081:80"
- "8444:443"
networks:
- xnetwork
links:
- xmysql:xmysql
depends_on:
- xmysql
volumes:
- ./haniapi/:/var/lib/volhaniapi/
xportal:
container_name: xportal
hostname: xportal
image: microsoft/dotnet:latest
# restart: always
tty: true
command: ["dotnet", "/var/lib/volhaniportal/hani.Portal.dll"]
ports:
- "8083:80"
- "8446:443"
networks:
- xnetwork
links:
- xmysql:xmysql
depends_on:
- xmysql
volumes:
- ./haniportal/:/var/lib/volhaniportal/
xfront:
container_name: xfront
hostname: xfront
image: nginx:stable-alpine
# restart: always
ports:
- "8082:80"
- "4445:443"
networks:
- xnetwork
links:
- xapi:xapi
depends_on:
- xapi
volumes:
- ./hanifront/:/usr/share/nginx/html
volumes:
data-volume: {}
# xvolmysql:
# driver: "local"
# xvolmongo:
# driver: "local"
# xvolrabbitmq:
# driver: "local"
# xvolstarapi:
# driver: "local"
networks:
xnetwork:
driver: bridge

Answer 1

When you make a connection from one Docker container to another, you always connect to the port the service inside the container is actually listening on. Any ports: mappings are ignored (and in fact you don't need ports: if you don't want the service to be accessible from outside Docker container space).
In your example, you need to change the port number in the connection string to the default MySQL port 3306.
(Consider removing all of the container_name:, hostname:, networks:, and links: blocks in the file. You should have an equivalent container stack with the same functionality; the two most observable differences are that if you directly use docker commands then the container names will be prefixed with the directory names, and the Docker-internal network will be named default. You can still use the service block names like xmysql as host names.)