Mounted MFEs with node_modules missing fail to start the server

[DawoudSheraz]

This issue is a similar issue to overhangio/tutor#997. The steps to reproduce are:

• Installed latest tutor master or nightly
• Clone any MFE repo (authn, learner-dashboard, etc.) and check out its appropriate branch (open-release/redwood.master if latest tutor master, master if tutor nightly)
• Add the cloned MFE as a bind mount
• Re-build mfe-dev images
• Run platform. Verify the mounted-MFE container runs into the error fedx-script not found
• Run npm install within cloned MFE repo on the host. Once installed, MFE dev container should be up and running.

Like the mentioned issue in tutor core, the bind-mounted MFE during image build does not get node_modules copied back to host. When running tutor, the host MFE directory without node_modules overrides the installed node_modules within image, thus resulting in fedx-script not found.

• Add a similar fix as core issue i.e. if node_modules are not found in MFE directory, run npm clean-install to install the required dependencies
  • If there is another fix, feel free to suggest it.

[hinakhadim]

I conclude to two solutions:

Solution 1:

While mounting, add this line in the volume: /openedx/app/node_modules. This line will make node_modules a volume (It won't call binding). Link to StackOverflow

authn: # Work on this MFE for development
      image: "docker.io/overhangio/openedx-authn-dev:18.0.0"
      ...
      volumes:
          - ../plugins/mfe/apps/mfe/webpack.dev-tutor.config.js:/openedx/app/webpack.dev-tutor.config.js:ro
          - /host-machine-path/.../frontend-app-authn:/openedx/app
          - /openedx/app/node_modules             # here, we're ignoring node_modules
      ...

Pros:

• When mounting /openedx/app, node_modules won't get overridden/mounted; in other words, we ignore the node_modules folder in the mounting process.
• The host machine doesn't need to install node_modules separately.
• The volume will persist; if you stop and restart the container, the volume won't get deleted.
• The volume gets deleted automatically when the container is deleted (tested).

Cons:

• To install a new package, users must install it in the container. Running npm i package-name won't work if it is done in the host-machine.
• If the mounted package.json has different dependencies than those at image build time, users need to run npm i in the container by themselves.

Solution 2:

As @DawoudSheraz mentioned this method above, we can install node_modules in the host machine project folder after the mounting process (this is binding; we are binding our host machine files to container files).

Pros:

• Users don't need to run npm i after the mounting process because the dependencies will be installed from the package.json of the user's forked project.

Cons:

• Separately install node_modules after the mount process through the job/task in host-machine.

Feel free to share if you have any other method to tackle this thing.

[DawoudSheraz]

@hinakhadim
For solution 1, when will the very first install after the mount happen? Will it be done manually inside container?

[hinakhadim]

@hinakhadim For solution 1, when will the first install after the mount happen? Will it be done manually inside container?

Solution 1 flow:

• Tutor is installed
• User clones the MFE and mounts it
• User runs tutor dev start
• Now, there are two cases:
  - If the packages mentioned in package.json of the cloned repo are similar to packages mentioned in package.json of openedx/frontend-app-* . Then, the container will start successfully.
  - If the packages are different, the container will start but will give the error "missing x module"

By using solution 1, we will not face fedx-scripts not found error. In volumes, the line /openedx/app/node_modules ignores node_modules mounting. It means the whole app will mount to /openedx/app and node_modules folder will not mount. As a result, installed node_modules (from the MFE image) will be used.

Solution 2 flow:

• Tutor is installed
• User clones the MFE and mounts it
• During the mounting process, the script will install node_modules by running npm install in cloned repo.
• User runs tutor dev start and the MFE container will be up.

@arbrandes @regisb any suggestions are highly appreciated.

[regisb]

I think the answer is to run npm clean-install as part of run tutor dev launch. One "mfe" init tasks could take care of running that command, as it is done in the LMS: https://github.com/overhangio/tutor/blob/master/tutor/templates/jobs/init/mounted-directories.sh