improvement: compatibility with Docker Compose subcommand

closes #641

CHANGELOG.md

@@ -20,6 +20,7 @@ Every user-facing change should have an entry in this changelog. Please respect
 
 - [Bugfix] Fix smtp server port in `cms.yml` which was causing email sending failures in the Studio. (by @regisb)
 - [Improvement] Use `git am` instead of `cherry-pick` to simplify patching process.
+- [Improvement] Tutor is now compatible with Docker Compose subcommand.
 
 ## v14.0.1 (2022-06-13)
 

docs/local.rst

@@ -5,6 +5,9 @@ Local deployment
 
 This method is for deploying Open edX locally on a single server, where docker images are orchestrated with `docker-compose <https://docs.docker.com/compose/overview/>`_.
 
+.. note::
+    Tutor is compatible with the ``docker compose`` subcommand. However, this support is still in beta and we're not sure it will behave the same as the previous ``docker-compose`` command. So ``docker-compose`` will be preferred, unless you set an environment variable ``TUTOR_USE_COMPOSE_SUBCOMMAND`` to enforce using ``docker compose``.
+
 .. _tutor_root:
 
 In the following, environment and data files will be generated in a user-specific project folder which will be referred to as the "**project root**". On Linux, the default project root is ``~/.local/share/tutor``. An alternative project root can be defined by passing the ``--root=...`` option to the ``tutor`` command, or defining the ``TUTOR_ROOT=...`` environment variable::

tutor/utils.py

@@ -1,4 +1,5 @@
 import base64
+from functools import lru_cache
 import json
 import os
 import random
@@ -162,12 +163,25 @@ def docker(*command: str) -> int:
     return execute("docker", *command)
 
 
+@lru_cache
+def _docker_compose_command() -> Tuple[str, ...]:
+    """
+    A helper function to determine which program to call when running docker compose
+    """
+    if os.environ.get("TUTOR_USE_COMPOSE_SUBCOMMAND") is not None:
+        return ("docker", "compose")
+    if shutil.which("docker-compose") is not None:
+        return ("docker-compose",)
+    if shutil.which("docker") is not None:
+        if subprocess.run(["docker", "compose"], capture_output=True).returncode == 0:
+            return ("docker", "compose")
+    raise exceptions.TutorError(
+        "docker-compose is not installed. Please follow instructions from https://docs.docker.com/compose/install/"
+    )
+
+
 def docker_compose(*command: str) -> int:
-    if shutil.which("docker-compose") is None:
-        raise exceptions.TutorError(
-            "docker-compose is not installed. Please follow instructions from https://docs.docker.com/compose/install/"
-        )
-    return execute("docker-compose", *command)
+    return execute(*_docker_compose_command(), *command)
 
 
 def kubectl(*command: str) -> int: