Memcached with SASL Authentication

This is a custom Docker image for Memcached (based on this docker compose setup in the Zulip docs), preconfigured to support SASL authentication using plain-text authentication. It automatically sets up the SASL configuration and password database at runtime.

I created it because I was trying to self-host Zulip via Dokku, and couldn't find a decent way to configure Memcached as in the above setup, using the Official memcached plugin for dokku.

Features

Memcached version 1.6.29-alpine
SASL authentication enabled
Custom environment variables for SASL configuration
Automatically generates the SASL configuration file and user password database

Usage

Build the Image

Clone the repository to your local machine:

git clone https://github.com/engineervix/docker-memcached-sasl.git
cd memcached-sasl

Build the Docker image:

docker build -t your-dockerhub-username/memcached-sasl .

Push the image to Docker Hub (or another container registry):
```
docker push your-dockerhub-username/memcached-sasl
```

Environment Variables

The following environment variables can be configured when running the container:

SASL_CONF_PATH: Path to the SASL configuration file (default: /home/memcache/memcached.conf).
MEMCACHED_SASL_PWDB: Path to the SASL password database (default: /home/memcache/memcached-sasl-db).
MEMCACHED_PASSWORD: Password used for the zulip user (default: "REPLACE_WITH_SECURE_MEMCACHED_PASSWORD").

How It Works

The entrypoint script creates the SASL configuration file at the location specified by SASL_CONF_PATH. This file enables the plain-text mechanism for SASL authentication.
The script generates a password database file (MEMCACHED_SASL_PWDB), containing credentials for the user zulip. The username is set as zulip@localhost with the password defined by MEMCACHED_PASSWORD.
The memcached -S command starts Memcached with SASL authentication enabled, enforcing user authentication for all clients.

Running the Image

You can run the image directly using Docker:

docker run -d \
  -e MEMCACHED_PASSWORD=your_secure_password \
  your-dockerhub-username/memcached-sasl

Or, use this image in a Dokku setup:

sudo dokku memcached:create memcached-zulip \
  --image "your-dockerhub-username/memcached-sasl" \
  --image-version "latest" \
  --custom-env "MEMCACHED_PASSWORD=your_secure_password"

Customization

If you want to customize the SASL mechanism or add more users, you can modify the Dockerfile or adjust the entrypoint script.
For a more secure setup, ensure that the MEMCACHED_PASSWORD environment variable is set to a strong, random value.

engineervix / docker-memcached-sasl