Failure to mount local volume when the volume is a child directory of pwd-CodePudding

I'm trying to start a service with docker-compose up where the volume is referencing ${PWD}/data. The data/ directory does not exist before docker-compose up is run.

This causes an exception. I thought the docker-compose up call would create {PWD}/data rather than giving this exception.

test-docker-compose_tor_1 is up-to-date
Creating test-docker-compose_walletserver_1 ... error

ERROR: for test-docker-compose_walletserver_1  Cannot create container for service walletserver: failed to mount local volume: mount /tmp/test-docker-compose/data:/var/lib/docker/volumes/bitcoin-s/_data, flags: 0x1000: no such file or directory

ERROR: for walletserver  Cannot create container for service walletserver: failed to mount local volume: mount /tmp/test-docker-compose/data:/var/lib/docker/volumes/bitcoin-s/_data, flags: 0x1000: no such file or directory
ERROR: Encountered errors while bringing up the project.

This is how i have the docker-compose.yml defined. How do i get my docker-compose.yml to create ${PWD}/data if the directory does not exist?

version: "3.8"

services:
  walletserver:
    image: bitcoinscala/bitcoin-s-server:latest
    entrypoint: ["/opt/docker/bin/bitcoin-s-server", "--datadir", "/bitcoin-s", "--conf", "/opt/docker/docker-application.conf"]
    restart: on-failure
    volumes:
      - datadir:/bitcoin-s 
volumes: 
  datadir:
    name: "bitcoin-s"
    driver: local
    external: false
    driver_opts:
      o: bind
      type: none 
      device: ${PWD}/data # note if i change this to ${PWD}, this works

Here are my versions

 docker --version                                                                                                    
Docker version 20.10.17, build 100c701

docker-compose version 1.29.2, build 5becea4c

CodePudding user response：

If you specify the volume as a bind mount in the service configuration, like this, it will work:

version: "3.8"

services:
  walletserver:
    image: bitcoinscala/bitcoin-s-server:latest
    entrypoint: ["/opt/docker/bin/bitcoin-s-server", "--datadir", "/bitcoin-s", "--conf", "/opt/docker/docker-application.conf"]
    restart: on-failure
    volumes:
      - ./data:/bitcoin-s

It looks like using the extended volume syntax has different behavior (arguably, the extended volume syntax has the correct behavior: automatically creating the directory may seem convenient, but it hides typos and can lead to unexpected behavior when you misspell a file and transform your config file into a directory).

CodePudding user response：

There are two different alternatives for mounting your directories from host into the container. One is using -v (or --volume) and the other one is --mount. The difference between these two is exactly what you asked for. By using -v docker would create the given directory in the location if it does not already exist and the other one returns an error.

Now for using this in docker-compose you can easily use the type tag for selecting the -v instead of --mount.

You can also specify the user id of the container using user: "${UID}:${GID}" or user: root on your docker-compose.yml

You would probably need something like this:

version: "3.8"

services:
  walletserver:
    image: bitcoinscala/bitcoin-s-server:latest
    user: "${UID}:${GID}"
    entrypoint: ["/opt/docker/bin/bitcoin-s-server", "--datadir", "/bitcoin-s", "--conf", "/opt/docker/docker-application.conf"]
    restart: on-failure
    volumes:
      - type: bind
        source: "datadir"
        target: "/bitcoin-s"