Unable to connect the mongodb container to node container in docker-CodePudding

The

CodePudding user response：

Try to connect not using localhost but a container name. So for example, if you want to connect to MongoDB from another container (in the same docker network) you can use mongodb:27017. It should work.

CodePudding user response：

When you run docker-compose up, the following happens:

A network called MernCrudApp(takes the default name of the directory) is created.

A container is created using the frontend's configuration. It joins the network MernCrudApp under the name frontend.

A container is created using the backend's configuration. It joins the network MernCrudApp under the name backend.

A container is created using mongodb’s configuration. It joins the network MernCrudApp under the name mongodb.

now if you use mongodb://localhost:27017/db_test to connect to the db, the node app will look for MongoDB in the backend container which you will get a connection error since it does not exist.

To remedy this, change the MongoDB connection string to mongodb://mongodb:27017/db_test so that it

Aditional comments
I would recommend the following to help solve some problems you might face in the future using the current configuration.

Add the connection string as an environment variable. This will make it easier for you to change the DB instances without rebuilding the container.

Since the backend application depends on the database add depend_on on the docker-compose files so that the MongoDB container starts before the backend container