fix: improve support of non-buildkit Docker build

See comment here:
https://github.com/overhangio/tutor/pull/868#issuecomment-1640429396

See also the conversation that spawned this PR:
https://discuss.openedx.org/t/issue-in-tutor-palm-release-with-tuotr-dev-launch-while-installing/10629

changelog.d/20230731_110301_regis_fix_non_buildkit_build.md

@@ -0,0 +1,4 @@
+- [Improvement] Improve support of legacy non-BuildKit mode: (by @regisb)
+  - [Bugfix] Fix building of openedx Docker image.
+  - [Improvement] Remove `--cache-from` build option.
+  - [Improvement] Add a warning concerning the lack of support of the `--build-context` option.

tests/commands/test_images.py

@@ -147,7 +147,6 @@ class ImagesTests(PluginsTestCase, TestCommandMixin):
                 "--target",
                 "target",
                 "docker_args",
-                "--cache-from=type=registry,ref=service1:1.0.0-cache",
             ],
             list(image_build.call_args[0][1:]),
         )

tutor/commands/images.py

@@ -223,16 +223,27 @@ def build(
             image_build_args = [*command_args, *custom_args]
 
             # Registry cache
-            if not no_registry_cache:
-                image_build_args.append(f"--cache-from=type=registry,ref={tag}-cache")
-            if cache_to_registry:
-                image_build_args.append(
-                    f"--cache-to=type=registry,mode=max,ref={tag}-cache"
-                )
+            if utils.is_buildkit_enabled():
+                if not no_registry_cache:
+                    image_build_args.append(
+                        f"--cache-from=type=registry,ref={tag}-cache"
+                    )
+                if cache_to_registry:
+                    image_build_args.append(
+                        f"--cache-to=type=registry,mode=max,ref={tag}-cache"
+                    )
 
             # Build contexts
             for host_path, stage_name in build_contexts.get(name, []):
-                image_build_args.append(f"--build-context={stage_name}={host_path}")
+                if utils.is_buildkit_enabled():
+                    fmt.echo_info(
+                        f"Adding {host_path} to the build context '{stage_name}' of image '{image}'"
+                    )
+                    image_build_args.append(f"--build-context={stage_name}={host_path}")
+                else:
+                    fmt.echo_alert(
+                        f"Unable to add {host_path} to the build context '{stage_name}' of image '{host_path}' because BuildKit is disabled."
+                    )
 
             # Build
             images.build(
@@ -257,9 +268,6 @@ def get_image_build_contexts(config: Config) -> dict[str, list[tuple[str, str]]]
         for image_name, stage_name in hooks.Filters.IMAGES_BUILD_MOUNTS.iterate(
             user_mount
         ):
-            fmt.echo_info(
-                f"Adding {user_mount} to the build context '{stage_name}' of image '{image_name}'"
-            )
             if image_name not in build_contexts:
                 build_contexts[image_name] = []
             build_contexts[image_name].append((user_mount, stage_name))

tutor/templates/build/openedx/Dockerfile

@@ -89,6 +89,9 @@ RUN {% if is_buildkit_enabled() %}--mount=type=cache,target=/openedx/.cache/pip,
     setuptools==67.6.1 pip==23.0.1. wheel==0.40.0
 
 # Install base requirements
+{% if not is_buildkit_enabled() %}
+COPY --from=edx-platform /requirements/edx/base.txt /openedx/edx-platform/requirements/edx/base.txt
+{% endif %}
 RUN {% if is_buildkit_enabled() %}--mount=type=bind,from=edx-platform,source=/requirements/edx/base.txt,target=/openedx/edx-platform/requirements/edx/base.txt \
     --mount=type=cache,target=/openedx/.cache/pip,sharing=shared {% endif %}pip install -r /openedx/edx-platform/requirements/edx/base.txt
 
@@ -123,6 +126,10 @@ RUN nodeenv /openedx/nodeenv --node=16.14.0 --prebuilt
 # Install nodejs requirements
 ARG NPM_REGISTRY={{ NPM_REGISTRY }}
 WORKDIR /openedx/edx-platform
+{% if not is_buildkit_enabled() %}
+COPY --from=edx-platform /package.json /openedx/edx-platform/package.json
+COPY --from=edx-platform /package-lock.json /openedx/edx-platform/package-lock.json
+{% endif %}
 RUN {% if is_buildkit_enabled() %}--mount=type=bind,from=edx-platform,source=/package.json,target=/openedx/edx-platform/package.json \
     --mount=type=bind,from=edx-platform,source=/package-lock.json,target=/openedx/edx-platform/package-lock.json \
     --mount=type=cache,target=/root/.npm,sharing=shared {% endif %}npm clean-install --no-audit --registry=$NPM_REGISTRY