Error: getaddrinfo ENOTFOUND trying to connect to mongo from container - docker

Question

I created an API using node.js
I converted it to an image by running the command docker build -t droneapi:1.0
using this Dockerfile.
FROM node:19-alpine
ENV MONGO_DB_USERNAME = admin \
MONGO_DB_PWD=password
RUN mkdir -p /home/droneAPI
COPY . /Users/styles/Programming/DroneAPI2
CMD ["node", "/Users/styles/Programming/DroneAPI2/Drones/server.js"]
I ran docker run droneapi:1.0 to create a container to talk to my mongodb container but I received the error: getaddrinfo ENOTFOUND mongodb
I’m using mongoose to try and communicate with the db
onst connectDB = async () => {
try{
const conn = await mongoose.connect("mongodb://admin:password#mongodb:27017", {dbName: 'drobedb'})
console.log(`MongoDB Connected: ${conn.connection.host}`.cyan.underline)
}catch (error){
console.log(`Error: ${error.message}`.red.underline.bold)
process.exit(1)
}
}
I have tried to replace the 'mongodb' in the connection string with localhost and I receive Error: connect ECONNREFUSED 127.0.0.1:27017
Here is my mongo.yaml file
version: '3'
services:
mongodb:
image: mongo
ports:
- 27017:27017
environment:
- MONGO_INITDB_ROOT_USERNAME=admin
- MONGO_INITDB_ROOT_PASSWORD=password
mongo-express:
image: mongo-express
ports:
- 8081:8081
environment:
- ME_CONFIG_MONGODB_ADMINUSERNAME=admin
- ME_CONFIG_MONGODB_ADMINPASSWORD=password
- ME_CONFIG_MONGODB_SERVER=mongodb
I'm new to docker so please any assistance will be appreciated

Answer 1

When we start a container stack through a compose-file, a network for this compose stack is created for us, and all containers are attached to this network. When we start a container through docker run ..., it is attached to the default network. Containers in different networks cannot communicate with each other. My recommendation would be to add the dronapi-container to the compose file:
version: '3'
services:
...
drone-api:
bulid:
context: .
dockerfile: path/to/Dockerfile
...
depends_on:
- mongodb # to start this container after mongodb has been started
If we want to start the stack, we can run docker compose up -d. Notice that if the image was built before, it will not be automatically rebuilt. To rebuild the image, we can run docker compose up --build -d.
As an aside: I would recommend following the 12 factors for cloud-native applications (12factors.net). In particular, I would recommend to externalize the database configuration (12factors.net).