Example Docker compose returns error - "a bytes-like object is required, not 'str'"

🚧 Installation
1

Running the example docker compose script provided by Nextcloud returns the following error:

Creating nextcloud_db_1 ... done
Creating nextcloud_app_1 ... done
Creating nextcloud_web_1 ...

ERROR: for nextcloud_web_1  a bytes-like object is required, not 'str'

ERROR: for web  a bytes-like object is required, not 'str'
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/docker/api/client.py", line 261, in _raise_for_status
    response.raise_for_status()
  File "/usr/lib/python3/dist-packages/requests/models.py", line 940, in raise_for_status
    raise HTTPError(http_error_msg, response=self)
requests.exceptions.HTTPError: 400 Client Error: Bad Request for url: http+docker://localhost/v1.22/containers/9067680bc0aec19af7192b56675c713f9a2b5f97b72120fc6d7fbc93e213613f/start

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/compose/service.py", line 625, in start_container
    container.start()
  File "/usr/lib/python3/dist-packages/compose/container.py", line 241, in start
    return self.client.start(self.id, **options)
  File "/usr/lib/python3/dist-packages/docker/utils/decorators.py", line 19, in wrapped
    return f(self, resource_id, *args, **kwargs)
  File "/usr/lib/python3/dist-packages/docker/api/container.py", line 1095, in start
    self._raise_for_status(res)
  File "/usr/lib/python3/dist-packages/docker/api/client.py", line 263, in _raise_for_status
    raise create_api_error_from_http_exception(e)
  File "/usr/lib/python3/dist-packages/docker/errors.py", line 31, in create_api_error_from_http_exception
    raise cls(e, response=response, explanation=explanation)
docker.errors.APIError: 400 Client Error: Bad Request ("b'OCI runtime create failed: container_linux.go:380: starting container process caused: process_linux.go:545: container init caused: rootfs_linux.go:76: mounting "/run/desktop/mnt/host/wsl/docker-desktop-bind-mounts/Ubuntu-20.04/c847f57279f05e17c5118010ad8b04a6cfc03ef4e0f603e89056a71c4f06c594" to rootfs at "/etc/nginx/nginx.conf" caused: mount through procfd: not a directory: unknown: Are you trying to mount a directory onto a file (or vice-versa)? Check if the specified host path exists and is the expected type'")

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/bin/docker-compose", line 11, in <module>
    load_entry_point('docker-compose==1.25.0', 'console_scripts', 'docker-compose')()
  File "/usr/lib/python3/dist-packages/compose/cli/main.py", line 72, in main
    command()
  File "/usr/lib/python3/dist-packages/compose/cli/main.py", line 128, in perform_command
    handler(command, command_options)
  File "/usr/lib/python3/dist-packages/compose/cli/main.py", line 1107, in up
    to_attach = up(False)
  File "/usr/lib/python3/dist-packages/compose/cli/main.py", line 1088, in up
    return self.project.up(
  File "/usr/lib/python3/dist-packages/compose/project.py", line 565, in up
    results, errors = parallel.parallel_execute(
  File "/usr/lib/python3/dist-packages/compose/parallel.py", line 112, in parallel_execute
    raise error_to_reraise
  File "/usr/lib/python3/dist-packages/compose/parallel.py", line 210, in producer
    result = func(obj)
  File "/usr/lib/python3/dist-packages/compose/project.py", line 548, in do
    return service.execute_convergence_plan(
  File "/usr/lib/python3/dist-packages/compose/service.py", line 545, in execute_convergence_plan
    return self._execute_convergence_create(
  File "/usr/lib/python3/dist-packages/compose/service.py", line 460, in _execute_convergence_create
    containers, errors = parallel_execute(
  File "/usr/lib/python3/dist-packages/compose/parallel.py", line 112, in parallel_execute
    raise error_to_reraise
  File "/usr/lib/python3/dist-packages/compose/parallel.py", line 210, in producer
    result = func(obj)
  File "/usr/lib/python3/dist-packages/compose/service.py", line 465, in <lambda>
    lambda service_name: create_and_start(self, service_name.number),
  File "/usr/lib/python3/dist-packages/compose/service.py", line 457, in create_and_start
    self.start_container(container)
  File "/usr/lib/python3/dist-packages/compose/service.py", line 627, in start_container
    if "driver failed programming external connectivity" in ex.explanation:
TypeError: a bytes-like object is required, not 'str'

For reference, here’s the docker-compose.yaml I’m running:

version: '2'

volumes:
  nextcloud:
  db:

services:
  db:
    image: mariadb
    restart: always
    command: --transaction-isolation=READ-COMMITTED --binlog-format=ROW
    volumes:
      - db:/var/lib/mysql
    environment:
      - MYSQL_ROOT_PASSWORD=*
      - MYSQL_PASSWORD=*
      - MYSQL_DATABASE=nextcloud
      - MYSQL_USER=nextcloud

  app:
    image: nextcloud:fpm
    restart: always
    links:
      - db
    volumes:
      - nextcloud:/var/www/html
    environment:
      - MYSQL_PASSWORD=*
      - MYSQL_DATABASE=nextcloud
      - MYSQL_USER=nextcloud
      - MYSQL_HOST=db

  web:
    image: nginx
    restart: always
    ports:
      - 8080:80
    links:
      - app
    volumes:
      - ./nginx.conf:/etc/nginx/nginx.conf:ro
    volumes_from:
      - app

Environment: Docker in Ubuntu running within a WSL layer (which should be invisible to Docker).

Edit: Just to note, I have the sample nginx.conf file provided sitting in the same directory beside docker-compose.yml

2

In case anybody else has the same issue: You need to provide an absolute path for nginx.conf.

3

The reason for this error is that in Python 3, strings are Unicode, but when transmitting on the network, the data needs to be bytes instead. We can convert bytes to string using bytes class decode() instance method, So you need to decode the bytes object to produce a string. In Python 3 , the default encoding is “utf-8” , so you can use directly:

b"python byte to string".decode("utf-8")

Python makes a clear distinction between bytes and strings . Bytes objects contain raw data — a sequence of octets — whereas strings are Unicode sequences . Conversion between these two types is explicit: you encode a string to get bytes, specifying an encoding (which defaults to UTF-8); and you decode bytes to get a string. Clients of these functions should be aware that such conversions may fail, and should consider how failures are handled.