Have you ever tried setting up a small Lightning Network on regtest to develop or demo against, and found it frustrating and confusing? lnet's goal is to make it easy to spin up any network topology for testing or demoing, all you need to do is describe the network in the graphviz dot format.

Take the following example, which will spin up two nodes, called client and server respectively, connect them and fund a channel. It'll also create an invoice on the server to balance the channel by sending over 500'000msat. You describe it, we make it happen.

graph g {
  client -- server [capacity="10000000:500000"];
}

A more complicated setup could be a star topology and some multi-hop paths:

graph g {
  client1 -- server [capacity="10000000"];
  client2 -- server [capacity="10000000"];
  client3 -- server [capacity="10000000"];
  client4 -- server [capacity="10000000"];
  client5 -- server [capacity="10000000"];
  
  "client5-1" -- client5 [capacity="10000000"];
  "client5-2" -- client5 [capacity="10000000"];
  "client5-3" -- client5 [capacity="10000000"];

}

lnet is just a simple pip install away:

pip3 install lnet

This will install the lnet-cli and lnet-daemon command line utilities. lnet-daemon starts, monitors and provides access to bitcoind and any number of c-lightning nodes, while lnet-cli is used to interact with the daemon and the nodes.

All operations are performed through lnet-cli, which will start lnet-daemon if required. lnet-cli has the following commands:

• start [dotfile] parses the dotfile, extracting nodes and channels, and tries to recreate the desired topology. It'll open channels and confirm them to make the usable, however it currently requires that the network topology is not partitioned. See below for attributes that are defined.
• stop stops the currently running topology
• shutdown stops the running topology and shuts down the lnet-daemon
• node [nodename] [rpc_method] [params...] executes rpc_method on the node with name nodename and the specified params. This is mainly used as a shorthand to give access without having to configure your shell.
• alias configures your shell with a number of aliases to make it easy to interact with the daemons without going through lnet-cli. You can use it with eval $(lnet-cli alias).