Azure Docker compose fails with the environment section

Question

I have a docker-compose.yml script working well in Azure. But when I add en environment section with two variables then it fails with this error:

2018-08-24 10:29:30.214 ERROR - Exception in multi-container config parsing: System.InvalidCastException: Specified cast is not valid.  
 at LWAS.Kube.ComposeFileParser.ParseContainer (System.Collections.Generic.KeyValuePair`2[TKey,TValue] service) [0x00152] in <029f376c1c6a4bb79892c2f60333c2d8>:0
 at LWAS.Kube.ComposeFileParser.ParseFile (System.String composeYaml) [0x000d2] in <029f376c1c6a4bb79892c2f60333c2d8>:0
 at LWAS.Kube.PodSpec.LoadSpecFromComposeYamlFile (System.String composeFile) [0x00000] in <029f376c1c6a4bb79892c2f60333c2d8>:0
 at LWAS.SiteStartInfoRepository.SetupPodSpecForMultiContainerApp (Microsoft.Web.Hosting.StartSiteContext ctx, LWAS.LinuxSiteStartInfo startInfo) [0x0000f] in <029f376c1c6a4bb79892c2f60333c2d8>:0
2018-08-24 10:29:30.215 ERROR - Start multi-container app failed

Shortened content of the docker-compose.yml file is:

version: '3.3'

services:
  application:
    image: myregistry.azurecr.io/application:latest
    volumes:
      - application_data:/usr/local/application/data

  proxy:
    image: myregistry.azurecr.io/proxy:latest
    depends_on:
      - application
    environment:
      - NGINX_HOST=myapplication.azurewebsites.net
      - NGINX_PORT=80
    ports:
      - "80:80"

volumes:
  application_data:

I tried:

1. to have only one variable
2. to use quotes around values i.e. NGINX_PORT="80"
3. to have whole variable definition in quotes i.e. "NGINX_PORT=80"
4. to rename variables using camel case i.e. nginxPort=80
5. to move environment section up and down

Nothing helped - still the same error message.

But it should be possible to use environment variables in Azure with Docker compose as it is shown here: https://learn.microsoft.com/en-us/dotnet/standard/microservices-architecture/multi-container-microservice-net-applications/multi-container-applications-docker-compose

Note: it works locally using docker-compose command without any problem. So it must be some Azure specific problem.

What am I doing wrong?

Thank you

Answer 1

Try:
- Removing the dashes in front of the environment values
- Changing '=' to ': ' for all environment values

version: '3.3'

services:
  application:
    image: myregistry.azurecr.io/application:latest
    volumes:
      - application_data:/usr/local/application/data

  proxy:
    image: myregistry.azurecr.io/proxy:latest
    depends_on:
      - application
    environment:
      NGINX_HOST: myapplication.azurewebsites.net
      NGINX_PORT: 80
    ports:
      - "80:80"

volumes:
  application_data:

Example yml from Microsoft:

version: '3.3'

services:
   db:
     image: mysql:5.7
     volumes:
       - db_data:/var/lib/mysql
     restart: always
     environment:
       MYSQL_ROOT_PASSWORD: somewordpress
       MYSQL_DATABASE: wordpress
       MYSQL_USER: wordpress
       MYSQL_PASSWORD: wordpress

   wordpress:
     depends_on:
       - db
     image: wordpress:latest
     ports:
       - "8000:80"
     restart: always
     environment:
       WORDPRESS_DB_HOST: db:3306
       WORDPRESS_DB_USER: wordpress
       WORDPRESS_DB_PASSWORD: wordpress
volumes:
    db_data:

Source: https://learn.microsoft.com/en-us/azure/app-service/containers/tutorial-multi-container-app