CONsistent Delivery Of Repositories

Problem

• apt uses the http protocol to grab repository metadata across multiple requests.

• No information is available to ensure consistency across resources, leading to errors such as:

    Failed to fetch http://[...]  Hash Sum mismatch
  

Solution

• Whenever we don't have a session for a client yet, or when it grabs InRelease or Release.gpg, we create a new session identified by reading a symlink. Sessions are per client, distribution and suite.

• We ask nginx (which does the heavy lifting of serving the data) to serve the files from a path created using this symlink.

• This only affects dists; pool is meant to be served as-is.

Usage

• Deploy behind nginx, with a configuration like:

    server {
        server_name repository.foo.com;
        listen 80;
  
        location / {
            proxy_pass http://127.0.0.1:8080;
            proxy_set_header X-Real-IP $remote_addr;
        }
        location /direct/ {
            internal;
            alias /var/lib/debian-repository/;
        }
    }
  

• Put an application.conf in your classpath overwriting any configuration you do not like (see src/resources/reference.conf).

Known issues

• NAT sucks. In short, you need to make sure that nginx will provide a unique enough X-Real-IP header for each client.