mongoose failing to connect in docker-compose - node.js

Question

I've got a simple docker-compose.yml that looks like this:
services:
mongodb-service:
image: mongo:latest
command: "mongod --bind_ip_all"
mongodb-seeder:
image: mongo:latest
depends_on:
- mongodb-service
command: "mongoimport --uri mongodb://mongodb-service:27017/auth --drop --file /tmp/users.json"
myapp:
image: myapp:latest
environment:
DATABASEURL: mongodb://mongodb-service:27017/auth
depends_on:
- mongodb-service
myapp is a nodejs app that uses mongoose to connect to a mongodb database like so:
const databaseURL = process.env.DATABASEURL;
async function connectToMongo() {
try {
return await mongoose.connect(databaseURL, {
useUnifiedTopology: true,
useNewUrlParser: true,
useCreateIndex: true,
});
}
catch (error) {
logger.error('MongoDB connect failure.', error);
}
}
mongodb-seeder works perfectly fine. I can kick it off, it connects to mongodb-service and runs the import without any problems. However, myapp starts up, tries to connect to mongodb-service for 30 seconds, then dies:
ERROR 2020-09-16T12:13:21.427 [MAIN] MongoDB connection error! [Arguments] {
'0': MongooseError [MongooseTimeoutError]: Server selection timed out after 30000 ms
...stacktrace snipped...
at Function.Module._load (internal/modules/cjs/loader.js:724:14) {
message: 'Server selection timed out after 30000 ms',
name: 'MongooseTimeoutError',
reason: Error: connect ECONNREFUSED 127.0.0.1:27017
at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1128:14) {
name: 'MongoNetworkError',
[Symbol(mongoErrorContextSymbol)]: {}
},
[Symbol(mongoErrorContextSymbol)]: {}
}
}
Note: The IP address in this log says it tried to connect to 127.0.0.1, not mongodb://mongodb-service:27017/auth. No matter what value I put in for DATABASEURL, it keeps printing 127.0.0.1. Any ideas why I can't get mongoose to recognize the hostname I'm giving it? And why would mongoose not be able to connect to a service that's clearly network-visible, since another container (mongodb-seeder) can see it without any problems?
Edit: I'm using mongoose 5.8.7

Answer 1

I was able to solve this on my own, turns out it was a pretty stupid miss on my part.
The DockerFile for my app defined an entrypoint that executed a script that exported the DATABASEURL prior to running. Removing that export allowed my environment: settings to flow down to the nodejs app.