# pyceo
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CEO (**C**SC **E**lectronic **O**ffice) is the tool used by CSC to manage
club accounts and memberships. See [architecture.md](architecture.md) for an
overview of its architecture.

## Development
First, make sure that you have installed the
[syscom dev environment](https://git.uwaterloo.ca/csc/syscom-dev-environment).
This will setup all of the services needed for ceo to work. You should clone
this repo in the phosphoric-acid container under ctdalek's home directory; you
will then be able to access it from any container thanks to NFS.

### Environment setup
Once you have the dev environment setup, there are a few more steps you'll
need to do for ceo.

#### Kerberos principals
First, you'll need `ceod/<hostname>` principals for each of phosphoric-acid,
coffee and mail. (coffee is taking over the role of caffeine for the DB
endpoints). For example, in the phosphoric-acid container:
```sh
kadmin -p sysadmin/admin
<password is krb5>
addprinc -randkey ceod/phosphoric-acid.csclub.internal
ktadd ceod/phosphoric-acid.csclub.internal
```
Do this for coffee and mail as well. You need to actually be in the
appropriate container when running these commands, since the credentials
are being added to the local keytab.
On phosphoric-acid, you will additionally need to create a principal
called `ceod/admin` (remember to addprinc **and** ktadd).

#### Database
create superuser `mysql` with password `mysql`
```
mysql -u root

CREATE USER 'mysql'@'localhost' IDENTIFIED BY 'mysql';
GRANT ALL PRIVILEGES ON *.* TO 'mysql'@'localhost' WITH GRANT OPTION;
```
modify superuser `postgres` for password authentication and restrict new users
```
su postgres
psql

ALTER USER postgres WITH PASSWORD 'postgres';
REVOKE ALL ON SCHEMA public FROM public;
GRANT ALL ON SCHEMA public TO postgres;
```
create a new `pg_hba.conf` to force password authentication and reject non local
```
cd /etc/postgresql/<version>/<branch>/
mv pg_hba.conf pg_hba.conf.old
```
```
# new pg_hba.conf
# TYPE  DATABASE        USER            ADDRESS                 METHOD
local   all             postgres                                md5
local   sameuser        all                                     md5
host    sameuser        all             0.0.0.0/0               md5
```
```
systemctl restart postgresql
```

#### Mailman
You should create the following mailing lists from the mail container:
```sh
/opt/mailman3/bin/mailman create syscom@csclub.internal
/opt/mailman3/bin/mailman create syscom-alerts@csclub.internal
/opt/mailman3/bin/mailman create exec@csclub.internal
/opt/mailman3/bin/mailman create ceo@csclub.internal
```
See https://git.uwaterloo.ca/csc/syscom-dev-environment/-/tree/master/mail
for instructions on how to access the Mailman UI from your browser.

If you want to actually see the archived messages, you'll
need to tweak the settings for each list from the UI so that non-member
messages get accepted (by default they get held).


#### Dependencies
Next, install and activate a virtualenv:
```sh
sudo apt install libkrb5-dev libsasl2-dev python3-dev
python3 -m venv venv
. venv/bin/activate
pip install -r requirements.txt
pip install -r dev-requirements.txt
```

#### C bindings
Due to the lack of a decent Python library for Kerberos we ended up
writing our own C bindings using [cffi](https://cffi.readthedocs.io).
Make sure you compile the bindings:
```sh
cd ceo_common/krb5
python krb5_build.py
```
This should create a file named '_krb5.cpython-37m-x86_64-linux-gnu.so'.
This will be imported by other modules in ceo.

## Running the application
ceod is a distributed application, with instances on different hosts offering
different services.
Therefore, you will need to run ceod on multiple hosts. Currently, those are
phosphoric-acid, mail and caffeine (in the dev environment, caffeine is
replaced by coffee).

To run ceod on a single host (as root, since the app needs to read the keytab):
```sh
export FLASK_APP=ceod.api
export FLASK_ENV=development
flask run -h 0.0.0.0 -p 9987
```

Sometimes changes you make in the source code don't show up while Flask
is running. Stop the flask app (Ctrl-C), run `clear_cache.sh`, then
restart the app.

## Interacting with the application
The client part of ceo hasn't been written yet, so we'll use curl to
interact with ceod for now.

ceod uses [SPNEGO](https://en.wikipedia.org/wiki/SPNEGO) for authentication,
and TLS for confidentiality and integrity. In development mode, TLS can be
disabled.

First, make sure that your version of curl has been compiled with SPNEGO
support:
```sh
curl -V
```
Your should see 'SPNEGO' in the 'Features' section.

The API also uses unconstrained Kerberos delegation when interacting with
the LDAP database. This means that the client obtains a forwarded TGT, then
sends that to ceod, which then uses it to interact with LDAP on the client's
behalf. There is a script called `gen_cred.py` which can generate this
ticket for you.


Here's an example of making a request to an endpoint which writes to LDAP:
```sh
# Get a Kerberos TGT first
kinit
# Obtain a forwarded TGT
./gen_cred.py phosphoric-acid
# Make the request
curl --negotiate -u : --service-name ceod \
    -H "X-KRB5-CRED: $(cat cred)" \
    -d '{"uid":"test_1","cn":"Test One","program":"Math","terms":["s2021"]}' \
    -X POST http://phosphoric-acid:9987/api/members
```