Erlangelist

This repository contains the complete source code of The Erlangelist site:

• Web site
• Articles
• Docker images
• Server setup

Contributing

If you want to contribute a minor correction to some article (e.g. language and grammar fixes) just make a pull request to the master. If you'd like to make a bigger change, please open a GitHub issue first.

Running the site locally

Prerequisites:

• Erlang 18
• Elixir 1.2
• PostgreSQL (preferably 9.4)

1. Start the database server on the port 5432.
2. Create the database user erlangelist with blank password.
3. Create the database erlangelist and grant all privileges to the erlangelist user.
4. Go to the site folder and fetch mix dependencies
5. From the site folder start the site with iex -S mix phoenix.server

If all went well, the server will listen on the port 20000.

Running tests

If you want to run tests, you need to create the erlangelist_test database, granting all privileges to the erlangelist user. Make sure to migrate the database (MIX_ENV=test mix ecto.migrate) and then you can start the test.

Deploying to the production server

Note: Don't deploy to a machine where you run some other system, or which is of some other importance to you. Setup script installs some packages and changes the system configuration (e.g. creates a user, modifies iptables rules, ...).

Server prerequisites

The target host must run Debian 8 and needs to have sudo installed. It also needs the Internet access, because various packages, docker images, and other dependencies are fetched during the initial setup and subsequent deploys.

There is a support available for starting a local Vagrant box that can act as a "staging" server. You need to first run cd provisioning/vagrant && VM_IP=192.168.54.54 vagrant up to start the server with a given IP address (feel free to use another IP address).

Client prerequisites

On your machine you need bash, ansible, and a git client. You also need to configure automatic passwordless ssh login to the server machine (under a login that has sudo privilege).

If you started a local Vagrant box, as explained above, you can run cd provisioning/vagrant && vagrant ssh-config --host ip_of_the_vm to get the ssh configuration for your server.

Filling in the blanks

You need to create the file site/config/prod_settings.exs which will contain your secrets (database password and secret_key_base). The file should look like:

[
  db_password: "super_secret_password",
  secret_key_base: "..."
]

You can run mix phoenix.gen.secret in the site folder to generate the secret key base.

In addition, you need to create provisioning/git_keys folder that must contain public keys of all allowed deployers.

Initial setup

This step installs required packages and sets up the system. You can run provisioning/setup-server.sh server_ip network_interface, where network interface is the name of the interface which accepts the requests from the outer world (for example eth0).

For example, to set up a local VM with an IP address 192.168.54.54, you can run provisioning/setup-server.sh 192.168.54.54 eth1.

Setting up the git remote

The deploy is performed by pushing to the git repository on the remote server. During the setup, the git user is created on the server. You can login as a git with any of the keys supplied in provisioning/git_keys folder, as explained above.

On your own machine, you need to add something like the following to your ~/.ssh/config:

Host 192.168.54.54
  User git
  PreferredAuthentications publickey
  IdentityFile private_key_path

In your local git repository, you need to add another remote which will be the deploy target. For example:

git remote add local_deploy [email protected]:erlangelist

Deploying

If all things are properly configured, you can simply deploy the site via

git push local_deploy master

The first push will run for some time, because it builds all the docker images from scratch. Once everything is done, the site should be listening at the port 80.