C#•2y ago

❔ ASP.NET Core (in container) is trying to connect to another container via localhost

The connection string specifies mongo as the hostname, but the API still tries to connect to [::1] which is the loopback IPv6 address (localhost) I have a Docker Compose file with containers - backend: ASP.NET Core web API - mongo: MongoDB which looks like this:

version: '3.4'

services:
  backend:
    image: home-api
    ports:
      - "2154:2154"
    build:
      context: ./api
      dockerfile: ./api/Dockerfile

  mongo:
    image: mongo
    restart: always
    ports:
      - "2155:27017"
    volumes:
      - ./Data:/data/db
    environment:
      MONGO_INITDB_ROOT_USERNAME: home-api
      MONGO_INITDB_ROOT_PASSWORD: home-api

version: '3.4'

services:
  backend:
    image: home-api
    ports:
      - "2154:2154"
    build:
      context: ./api
      dockerfile: ./api/Dockerfile

  mongo:
    image: mongo
    restart: always
    ports:
      - "2155:27017"
    volumes:
      - ./Data:/data/db
    environment:
      MONGO_INITDB_ROOT_USERNAME: home-api
      MONGO_INITDB_ROOT_PASSWORD: home-api

With the API, I followed two tutorials: - https://learn.microsoft.com/en-us/aspnet/core/web-api/?WT.mc_id=dotnet-35129-website&view=aspnetcore-7.0 - https://learn.microsoft.com/en-us/aspnet/core/tutorials/first-mongo-app?view=aspnetcore-7.0&tabs=visual-studio-code I then containerized it and started mongod in a ./Data directory. When connecting to the database (on the mongo container) with this appsettings.json

{
  "HomeDatabase": {
    "ConnectionString": "mongodb://home-api:home-api@mongo:27017/Home.Users?authSource=admin",
    "DatabaseName": "Home",
    "UsersCollectionName": "Users"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*"
}

{
  "HomeDatabase": {
    "ConnectionString": "mongodb://home-api:home-api@mongo:27017/Home.Users?authSource=admin",
    "DatabaseName": "Home",
    "UsersCollectionName": "Users"
  },
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*"
}

I recieve an error from the backend container. (attached) New to MongoDB, Docker, and ASP.NET. Let me know if you want any additional information.

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error.txt

19 Replies

Saber•2y ago

don't use mongo, but the connection string looks weird to me. shouldn't it be like mongodb://mongo:27017

circles.png•2y ago

according to the official mongo docs the connection string has a username and password https://mongodb.github.io/mongo-java-driver/3.11/javadoc/com/mongodb/ConnectionString.html changing the connection string to mongodb://mongo:27017 still has the same error how do i know that when i docker compose up it updates the containers?

jcotton42•2y ago

pass --build it won't otherwise, iirc there's also --force-recreate

circles.png•2y ago

oh thanks i got it so that it only has an authorization error where does mongodb store the database? (in the container so i can put it in a volum)

jcotton42•2y ago

read the docs for the container most of them are on hub.docker.com

jcotton42•2y ago

a search for "mongo" brings up https://hub.docker.com/_/mongo

mongo - Official Image | Docker Hub

MongoDB document databases provide high availability and easy scalability.

circles.png•2y ago

now when trying to access mongo i have "authorization failed"

jcotton42•2y ago

anything in the logs for the mongo container? did you put the credentials back in the connection string?

circles.png•2y ago

yea they are correct how can i see if the database in the container has the user?

jcotton42•2y ago

idk mongo, so can't help you there

circles.png•2y ago

its ok couldnt find user

jcotton42•2y ago

have the MONGO_INITDB_ROOT_USERNAME and MONGO_INITDB_ROOT_PASSWORD environment keys always been in that compose file? if you added them after the first run, mongo might not read them, and thus not create the user you need

circles.png•2y ago

they have always been

{"t":{"$date":"2023-01-21T02:35:59.127+00:00"},"s":"I",  "c":"ACCESS",   "id":20249,   "ctx":"conn3","msg":"Authentication failed","attr":{"mechanism":"SCRAM-SHA-1","speculative":false,"principalName":"home-api","authenticationDatabase":"admin","remote":"192.168.16.3:58332","extraInfo":{},"error":"UserNotFound: Could not find user \"home-api\" for db \"admin\""}}

{"t":{"$date":"2023-01-21T02:35:59.127+00:00"},"s":"I",  "c":"ACCESS",   "id":20249,   "ctx":"conn3","msg":"Authentication failed","attr":{"mechanism":"SCRAM-SHA-1","speculative":false,"principalName":"home-api","authenticationDatabase":"admin","remote":"192.168.16.3:58332","extraInfo":{},"error":"UserNotFound: Could not find user \"home-api\" for db \"admin\""}}

thats the line

jcotton42•2y ago

you could try docker compose down -v, that will remove the built containers and their volumes, to start from a clean slate when you do up again, pay close attention to the mongo logs

circles.png•2y ago

got it

circles.png•2y ago

entire log if you wanted it

message.txt

jcotton42•2y ago

hmmmmmm lemme run the mongo container locally ok so if I do it locally via DataGrip I can connect oh wait @circles.png did you also clear out ./Data after you did docker compose down -v? b/c if not, it'll probably just be reusing the auth database

circles.png•2y ago

wow that worked but my (test) data is gone i will mark as solved after i get it working

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ ASP.NET Core (in container) is trying to connect to another container via localhost