Distributed E-Mail-Service Implemented With CRDTs

Localhost : General

Generally each host has an id, a port and a hostname. Further there is a settings file located in settings/host_ID for each host. By default python manage.py runserver will start the server with the settings/host_0 file. The initial setup includes three hosts.

• The hostlist is given in line 19-23:

ALL_HOSTS = [
	{'id' : 0, 'port' : 8000, 'hostname' : "http://127.0.0.1"},
	{'id' : 1, 'port' : 8001, 'hostname' : "http://127.0.0.1"},
	{'id' : 2, 'port' : 8002, 'hostname' : "http://127.0.0.1"},
]

• And the running host is specified in line 25:

RUNNING_HOST = ALL_HOSTS[ID]

• The connection to the postgres database can be configured in line 6-15:

DATABASES = {
    'default': {
        'ENGINE': 'django.db.backends.postgresql_psycopg2',
        'NAME': 'db_host_ID',
        'USER': 'postgres',
        'PASSWORD': 'postgres',
        'HOST': 'localhost',
        'PORT': '5432',
    }
}

Localhost : Getting started

On Ubuntu simply follow this instruction to deploy an instance of the E-Mail-Service.

Install postgres, by:

sudo apt-get install postgresql postgresql-contrib

In a terminal, type:

sudo -u postgres psql postgres

Set "postgres" as a password for the "postgres" database role using the command:

\postgres postgres

Type Control+D or \q to exit the posgreSQL prompt.

To create the database, type:

sudo -u postgres createdb db_host_ID

Install system packages:

sudo apt-get install python-pip python-psycopg2

Get the django framework with pip:

sudo pip install django

Finally, clone the repository:

git clone https://github.com/aaltenbernd/crdt.git

Make migrations, by:

python crdt/manage.py makemigrations

And migrate these to the database:

python crdt/manage.py migrate --settings=settings.host_ID

Start the instance, by:

python crdt/manage.py run_host --settings=settings.host_ID

If you want to clear the database, type:

python crdt/manage.py init --settings=settings.host_ID

Develop on different hosts

On Ubuntu simply follow the instruction ahead on each host.

Afterwards configure the hostlist in the settings/host_ID file and manipulate the IPs:

ALL_HOSTS = [
	{'id' : 0, 'port' : 8000, 'hostname' : "http://IP_HOST_0"},
	{'id' : 1, 'port' : 8001, 'hostname' : "http://IP_HOST_1"},
	{'id' : 2, 'port' : 8002, 'hostname' : "http://IP_HOST_2"},
]

And start the host, by:

python crdt/manage.py run_host --settings=settings.host_ID --production

Test

Start a simple test, by:

python crdt/crdt/test/test_random.py

If the E-Mail-Service is developed on different hosts, also configure the hostlist in line 14-18 and start the test, by:

ENV=production python crdt/crdt/test/test_random.py