Add support for Moodle/LTI and email/password-based authentication #362

erikmd · 2020-09-16T00:25:05Z

Description

This development is a joint work with @Aleridia and @agrn that completed their internship in Toulouse this summer.

This PR adds the following features to learn-ocaml:

the ability to send e-mails for account confirmation & password change/reset (assuming the new option use_passwd is enabled)
the ability to authenticate from a Moodle server (hosted apart, e.g. in one's university) using the so-called LTI protocol, allowing one to sign-up and sign-in very easily (assuming both options use_moodle and use_passwd have been enabled)
the ability to "upgrade" a legacy token-based account to a password-based and/or LTI-based account, while keeping the same underlying /sync architecture based on tokens, which are still "unique IDs" identifying the accounts, albeit login for new accounts and upgraded accounts is specifically performed with an e-mail address (or by a LTI request).

Important notes

This PR depends on Refactor token index #354, so these two PRs Refactor token index #354 and Add support for Moodle/LTI and email/password-based authentication #362 should be merged in a row.
As usual, the *.opam* files (and dune-project) should be bumped (e.g. to 0.13) before the upcoming release, but I did not include this commit in this PR because it would make the PR unmergeable otherwise (due to a conflict with this already-integrated commit).
The server API has been modified/extended since 0.12 as needed by these features, but the /sync folders created with 0.12 are fully compatible, given all the new metadata is stored in /sync/data/, and great care has been put into making the migration smooth from 0.12 to (upcoming) 0.13, whatever is the chosen config:
- use_passwd=false, use_moodle=false (backward-compatible choice)
- use_passwd=true, use_moodle=false (email/pass auth)
- use_passwd=true, use_moodle=true (email/pass auth + Moodle/LTI support)

How to test it?

Deploying a complete dev environment to test this PR is very easy using docker-compose.
First, create a file demo-repository/server_config.json containing:

{
    "use_passwd": true,
    "use_moodle": true
}

then you should just need to run:

cd .../learn-ocaml
git pr 362  # using this git alias
docker-compose up --build
xdg-open http://localhost:8080  # learn-ocaml application
xdg-open http://localhost:1080  # web-based, ephemeral mail user agent
xdg-open http://localhost:9090  # dockerized Moodle server (login=user, passwd=bitnami)

Anyway, note that if you don't want to rely on these features:

The usual ocaml-based deployment is still possible: make && make opaminstall && learn-ocaml --repo=demo-repository
likewise for the standard, single-container Docker deployment;
and static deployment (e.g. using GitHub Pages, without a backend) is still possible since Fix static deployment #356
(documentation for Fix static deployment #356 should be added though)

Status of the PR and checklist

All points that had been raised in the video meeting / review with @yurug, and subsequently in later tests have been addressed and the current version of the code has been successfully deployed (I hope it'll be further tested thanks to ~180 students in the upcoming days :)

Note that the docker-compose.yml file gathered in this PR only brings a "dev / test" environment.

Regarding the "prod" environment, a configuration template (without Moodle, but with a dockerized mail transfer agent) is available in the following repo: https://github.com/pfitaxel/docker-learn-ocaml

A couple of tasks remain though:

Rename/Make environment variables FROM_DOMAIN SMTPSERVER, EMAIL documented in Cmdliner
Add more documentation in the docs folder [mandatory]
Bump cohttp versions to relax a bit the "upward" (<) constraints [optional, advised by opam maintainers]
Investigate the perms warning that appeared here;
Check/fix/update compatibility with the emacs front-end: https://github.com/pfitaxel/learn-ocaml.el

Ideally, I guess that the first task should be performed as part of this PR (I'll have a look ASAP) and the three others could be done likewise, or possibly after the PR merge? just before the 0.13 release anyway… that might occur in October, maybe?
Cc @yurug FYI