Cogini Blog
Articles by elixir
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Deploying an Elixir app to Digital Ocean with mix_deploy
The impact of network latency, errors, and concurrency on benchmarks
The goal of benchmarking is to understand the performance of our system and how to improve it. When we are making benchmarks, we need to make sure that they match real world usage. In my post on Benchmarking Phoenix on Digital Ocean, changing the concurrent connections and network latency had … Read more…
Managing app secrets with Ansible
In web applications we usually have a few things that are sensitive, e.g. the login to the production database or API keys used to access a third party API. We need to be particularly careful about how we manage these secrets, as they may allow attackers to access data … Read more…
Deploying your Phoenix app to Digital Ocean for beginners
This is a gentle introduction to getting your Phoenix app up and running on a $5/month server at Digital Ocean. It starts from zero, assuming minimal experience with servers. Read more…
Benchmarking Phoenix on Digital Ocean
Just for fun, I decided to benchmark the performance of the elixir deploy template running on a $5/month Digital Ocean Droplet. Read more…
Avoiding GenServer bottlenecks
GenServers are the standard way to create services in Elixir. At it's heart, a GenServer is a separate process (thread) that receives messages, does some work, manages state, and sends responses back. If that's what you want, great. It's important to recognize, though, that a GenServer only handles one request … Read more…
Database migrations in the cloud
Database migrations are used to automatically keep the database in sync with the code that uses it. Elixir apps should be deployed as releases, supervised by systemd. Here is an example of how to run migrations when deploying Elixir releases. It's tempting to automatically run database migrations when the app … Read more…
Deploying Elixir apps without sudo
We normally deploy Elixir apps as releases, supervised by systemd. After we have deployed the new release, we restart the app to make it live: sudo /bin/systemctl restart foo The user account needs sufficient permissions to restart the app, though. Instead of giving the deploy account full sudo permissions … Read more…
Getting the client public IP address in Phoenix
When your app is running behind a proxy like Nginx or a CDN, then the requests will all look like they are coming from the proxy. Use the X-Forwarded-For header to set the remote_ip correctly. Read more…
Serving your Phoenix app with Nginx
It's common to run web apps behind a proxy such as Nginx or HAProxy. Nginx listens on port 80, then forwards traffic to the app on another port, e.g. 4000. Following is an example nginx.conf config: user nginx; worker_processes auto; error_log /var/log/nginx/error.log warn; pid … Read more…
Serving Phoenix static assets from a CDN
Phoenix is fast, but you can improve performance by serving requests for static files like images, CSS and JS from Nginx or a content delivery network (CDN). This allows your app to focus on dynamic content. Serving static assets from Nginx If you are running your app behind Nginx, configure … Read more…