How can I add a volume for the App_Data folder using docker-compose.override.yml? - visual-studio

Question

I am experimenting with Visual Studio's docker support and want to add a volume mount for C:\inetpub\wwwroot\App_Data.
My Dockerfile looks like this:
FROM microsoft/aspnet:4.7.1-windowsservercore-1709
ARG source
WORKDIR /inetpub/wwwroot
COPY ${source:-obj/Docker/publish} .
My docker-compose.yml file looks like this:
version: '3.4'
services:
my.app:
image: ${DOCKER_REGISTRY}myapp
build:
context: .\My.App
dockerfile: Dockerfile
Now I've tried just about every variation of specifying volumes in my docker-compose.override.yml file, including:
version: '3.4'
services:
my.app:
volumes:
- "C:\\inetpub\\wwwroot\\App_Data"
ports:
- "80"
networks:
default:
external:
name: nat
services:
my.app:
volumes:
- "C:\\temp\\dockerappdata1":"C:\\inetpub\\wwwroot\\App_Data"
ports:
- "80"
networks:
default:
external:
name: nat
services:
my.app:
volumes:
- type: volume
source: "app_data"
target: "C:\\inetpub\\wwwroot\\App_Data"
ports:
- "80"
networks:
default:
external:
name: nat
volumes:
app_data:
But in all cases, I cannot run the project and it reports either some kind of configuration issue with compose or else an issue when starting the container, with the super-unhelpful message:
encountered an error during Start: failure in a Windows system call: The compute system exited unexpectedly.
What is the right syntax?

Answer 1

version: '3.4'
services:
my.app:
volumes:
- "C:\\inetpub\\wwwroot\\App_Data"
ports:
- "80"
networks:
default:
external:
name: nat
services:
my.app:
volumes:
- "C:\\temp\\dockerappdata1":"C:\\inetpub\\wwwroot\\App_Data"
ports:
- "80"
networks:
default:
external:
name: nat
services:
my.app:
volumes:
- type: volume
source: "app_data"
target: "C:\\inetpub\\wwwroot\\App_Data"
ports:
- "80"
networks:
default:
external:
name: nat
volumes:
app_data:
The problem I think here is, you are trying to mount a directory which is already there.

Answer 2

If I understand your question correctly, you'd like to volume mount "C:\inetpub\wwwroot\App_Data" into the container, correct?
If that's the case, here's what you should add in the yaml file:
services:
my.app:
volumes:
- C:\\inetpub\\wwwroot\\App_Data:C:\\temp\\dockerappdata1
# Syntax is HOST_PATH:CONTAINER_PATH:[ro/rw] (the access mode is optional)
ports:
- "80"
More info on the syntax: https://docs.docker.com/compose/compose-file/#short-syntax-3