LANcache

Automatically cache game files and updates at LAN parties using Nginx as a reverse proxy.

Forked from Lochnair/lancache

Requirements

• Ubuntu 16.04
• A DNS server to redirect clients to the cache
• sniproxy to serve HTTPS requests

Installation

Enter an interative superuser shell:

sudo -i

Create the Nginx config directory:

mkdir /etc/nginx && cd /etc/nginx

Clone the zeropingheroes/lancache repository into it:

git clone https://github.com/zeropingheroes/lancache.git .

Make all the scripts in the install directory executable:

chmod -R +x /etc/nginx/install/

Compile Nginx from source:

/etc/nginx/install/compile-nginx.sh

Prepare directories:

/etc/nginx/install/prepare-directories.sh

Install Nginx as a service to start at boot:

/etc/nginx/install/install-nginx-service.sh

Start Nginx:

systemctl start nginx

Configuration & Usage

Maximum Cache Size

To limit how much space the cache data folder can use, edit:

includes/proxy-cache-paths.conf

Adjust max_size=1000g to fit your needs.

Enabling/Disabling Caches

Enabling

ln -s /etc/nginx/caches-available/cache-name.conf /etc/nginx/caches-enabled/cache-name.conf

Disabling

rm /etc/nginx/caches-enabled/cache-name.conf

Clearing Cache

To completely clear everything in the cache, run

/etc/nginx/scripts/clear-cache.sh

Statistics

To find out what's stored in the cache, how much data has been served and which clients have been using the cache, set up Filebeat and ELK to parse logs and show visual statistics.

On Your Lancache Server

1. Install Filebeat

2. Install Lancache Filebeat configuration file:

/etc/nginx/install/install-filebeat-config.sh

On Your Statistics Server

1. Install ELK

2. Set up zeropingheroes/lancache-elk

Known Issues

Cache Corruption

In the very unlikely event that the cache stores and serves up a corrupted file, only some download clients handle this helpfully for us:

• Blizzard - OK - Re-requests the file with headers Pragma: no-cache and Cache-control: no-cache which causes Nginx to bypass the cache and request a fresh copy of the file from upstream
• Steam - Not OK - Steam will re-request a corrupt file from the cache over and over, but will never send Pragma: no-cache and Cache-control: no-cache headers. This causes the game download to never complete
• Origin - Not OK - All requests are sent with Pragma: no-cache and Cache-control: no-cache and we ignore these or nothing would be cached. If a file is corrupt in the cache there is no mechanism for the Origin client to request Nginx fetches a fresh copy of the file from upstream
• Windows Update - Untested
• Riot - Untested

Incorrect Cache Hit/Miss Stats for Blizzard and Origin

Because we use slice for these upstreams, Nginx reports a cache hit for almost all requests from clients, as the single client request has spawned one or more subrequests which fill the cache. If you have a workaround for this behaviour, please submit a pull request.

Contributing

Please submit pull requests to useful changes and enhancements.

I'd reccomend you read Nginx's Caching blog post to understand caching before diving straight in.

Below are a few ways you can help:

Caching Another Content Provider

Create Files

Each cache has two files:

• caches-available/cache-name.conf - Defines basic logging info
• upstreams/cache-name.conf - Defines what should be cached

Duplicate an existing cache's files as a template.

Edit Configuration

Server Names

Set the primary server name to lancache-(cachename)

server_name lancache-battletoads;

For all other server names, you must discover each FQDN a content provider uses to serve content and add it to the list of server names.

server_name content1.battletoads.net;

Proxy & Cache / Proxy Only

Each location {} context can either include includes/proxy-cache-upstream.conf to proxy and cache the upstream, or include includes/proxy-upstream.conf to only proxy, and not cache any content.

Directives in these files can be overriden in the parent configuration after the include statement.

location / {
    # Load settings to only proxy this upstream location (no caching)
    include includes/proxy-upstream.conf;
}

location / {
    # Load settings to proxy and cache this upstream location
    include includes/proxy-cache-upstream.conf;

    # Cache data in the cache named "installers" 
    proxy_cache installers;