@ -248,8 +248,120 @@ C-lightning is a lightweight, highly customizable, and standard-compliant implem
https://github.com/ElementsProject/lightning
In the following sections, we will build a docker container that runs a c-lightning node connecting to the bitcoind container we build previously. We will also show you how to configure and build the c-lightning software directly from the source code.
==== Building c-lightning as a Docker container
The c-lightning software distribution has a docker container, but it is designed for running c-lightning in production systems and along side a bitcoind node. We will be using a somewhat simpler container configured to run c-lightning for demonstration purposes.
We start by building the c-lightning docker container, from the book's files which you previously downloaded into a directory named +lnbook+. As before, we will use the +docker build+ command, in the +code/docker+ sub-directory. We will tag the container image with the tag +lnbook/c-lightning+, like this:
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$ cd code/docker
$ docker build -t lnbook/c-lightning c-lightning
Sending build context to Docker daemon 10.24kB
Step 1/21 : FROM lnbook/bitcoind AS c-lightning-base
Our container is now built and ready to run. However, before we run the c-lightning container, we need to start the bitcoind container in another terminal, as c-lightning depends on bitcoind. We will also need to set up a docker network that allows the containers to connect to each other, as if they are on the same local area network.
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Docker containers can "talk" to each other over a virtual local-area network managed by the docker system. Each container can also have a custom name and other containers can use that name to resolve its IP address and easily connect to it.
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==== Setting up a docker network
Once a docker network is set up, docker will keep it running on our local computer every time docker starts, for example after rebooting. So we only need to set up a network once, using the +docker network create+ command. The network name itself is not important, but has to be unique on our computer. By default, docker has three networks named +host+, +bridge+, and +none+. We will name our new network +lnbook+ and create it like this:
As you can see, running +docker network ls+ gives us a listing of the docker networks. Our +lnbook+ network has been created. We can ignore the network ID, as it is automatically managed.
==== Running the bitcoind and c-lightning containers
Let's start the +bitcoind+ and +c-lightning+ containers and connect them to the +lnbook+ network. To run a container in a specific network, we must pass the +network+ argument to +docker run+. To make it easy for containers to find each other, we will also give each one a name with the +name+ argument. We start +bitcoind+ like this:
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$ docker run -it --network lnbook --name bitcoind lnbook/bitcoind
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You should see +bitcoind+ start up and start mining blocks every 10 seconds. Leave it running and open a new terminal window to start c-lightning. We use a similar +docker run+ command, with the +network+ and +name+ arguments to start c-lightning, like this:
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$ docker run -it --network lnbook --name c-lightning lnbook/c-lightning
2020-06-22T14:26:09.802Z DEBUG lightningd: Opened log file /lightningd/lightningd.log
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The +c-lightning+ container starts up and connects to the +bitcoind+ container over the docker network. First, our c-lightning node will wait for bitcoind to start and then it will wait until bitcoind has mined some bitcoin into its wallet. Finally, as part of the container startup, a script will send an RPC command to the bitcoind node, creating a transaction that funds the c-lightning wallet with 10 test BTC. Our c-lightning node is not only running, but it has some bitcoin to play with!
As we demonstrated with the +bitcoind+ container, we can issue commands to our +c-lightning+ container in another terminal, to extract information, open channels etc. The command that allows us to issue command-line instructions to the c-lightning node is called +lightning-cli+. Let's get the node info, in another terminal window, using the +docker exec+ command:
We now have our first Lightning node running on a virtual network and communicating with a test bitcoin blockchain. Later in this chapter we will start more nodes and connect them to each other to make some Lightning payments.
In the next section we will also look at how to download, configure and compile c-lightning directly from the source code. This is an optional and advanced step that will teach you how to use the build tools and allow you to make modifications to c-lighting source code. With this knowledge, you can write some code, fix some bugs, or create a plugin for c-lightning. If you are not planning on diving into the source code or programming of a Lightning node, you can skip the next section entirely. The docker container we just built is sufficient for most of the examples in the book.
==== Installing c-lightning from source code
The c-lightning developers have provided detailed instructions for building c-lightning from source code. We will be following the instructions here:
If all goes well, you will see no +ERROR+ message stopping the execution of the above command. The c-lightning software package has been compiled from source and we are now ready to install the executable packages:
If all goes well, you will not see any +ERROR+ message stopping the execution of the above command. The c-lightning software package has been compiled from source and we are now ready to install the executable packages:
Andreas M. Antonopoulos
4 years ago