clyde

clyde is meant to be used in addition to cpcache. Its purpose is to keep the cache warm, i.e., to download packages from the cache such that subsequent HTTP GET requests of the same package can be fulfilled without having to download the file from a remote mirror.

Installation

Server Configuration

Before continuing, please make sure that cpcache is running. Check the output of systemctl status cpcache to verify that cpcache is listening on its standard port 7070 for incoming requests.

First, we need to create a key which will be used to authorize HTTP POST requests sent by clyde-client to cpcache. This key is shared between all clients and servers, so it has to be generated only once. The key should not contain any characters that are not suited to be sent in an HTTP request. You can use openssl to generate a suitable key for you:

$ openssl rand -hex 25
34f449e4050605ccd1720071cafd00489e448c95b25c963f69

Add this key to the the config file of cpcache. In /etc/cpcache/cpcache.toml, search for recv_packages. As explained by the comments in this section of the file, you'll have to uncomment the two lines and add your key:

[recv_packages]
    key = "34f449e4050605ccd1720071cafd00489e448c95b25c963f69"

Remember to restart cpcache after having changed its configuration:

systemctl restart cpcache

Then, install clyde-server. clyde-server uses /etc/clyde_server/config.toml as its configuration file. If you're using the default settings of cpcache, you can leave this file as it is. If you have changed cache_directory setting of cpcache, you will have to replace all occurrences of /var/cache/cpcache by your chosen cache directory. When clyde-server has been installed and you have verified that the config file is correct, you can start and enable the timer:

systemctl start clyde_server.timer
systemctl enable clyde_server.timer

Client Configuration

Note that we use cpcache.local as the hostname for cpache. Replace it by whatever IP address or hostname can be used to reach cpcache inside your own LAN. Repeat the following steps on all machines that are used as clients (i.e., all machines that use cpcache as pacman cache):

1. Adapt your /etc/pacman.d/mirrorlist so that clyde-client know how to reach cpcache. clyde-client looks for the line # cpcache and assumes that the following line is the address of the server running cpcache. For instance, with cpcache.local being the hostname of the machine running cpcache, you would add the following line to your mirrorlist file:

   # cpcache
   Server = http://cpcache.local:7070/$repo/os/$arch

2. Create the directory /etc/clyde_client and add the key to a file named key inside this directory:

   mkdir /etc/clyde_client
   echo 34f449e4050605ccd1720071cafd00489e448c95b25c963f69 > /etc/clyde_client/key

3. Next, we can continue to install clyde-client. Check the pacman output after installing clyde-client. You should see a message such as:

   :: Running post-transaction hooks...
   (1/2) Sending list of installed packages to cpcache
   

   clyde-client uses pacman hooks so that after each upgrade or package removal run by pacman, all packages required by the client will be sent to cpcache. To make sure that cpcache successfully receives this message, check the journal of cpcache (e.g. systemctl status cpcache). It should log a message such as Successfully written file /var/cache/cpcache/wanted_packages/arch-vm for host arch-vm.

Now, the server knows which packages are required by inspecting the files inside the directory /var/cache/cpcache/wanted_packages. clyde-server will run each night at around 4 o'clock (± one hour). For each package used by at least one client, it will fetch the most recent version, unless already present.