Chapter node_client: installing LND from source

node_client.asciidoc

@@ -674,7 +674,65 @@ In the next section we will also look at how to download and compile LND directl
 
 ==== Installing LND from source code
 
+In this section we will build LND from scratch. LND is written in the Go programming language (search for golang to avoid irrelevant results on the word "go"). Because it is written in Go and not C or C++, it uses a different "build" framework than the GNU autotools/make framework we saw used in c-lightning previously. Don't fret though, it is quite easy to install and use the golang tools and we will show each step here. Go is a fantastic language for collaborative software development as it produces very consistent, precise and easy to read code regardless of the number of authors. Go is focused and "minimalist" in a way that encourages consistency across versions of the language. As a compiled language, it is also quite efficient. Let's dive in.
 
+We will follow the installation instructions found on the LND project documentation:
+
+https://github.com/lightningnetwork/lnd/blob/master/docs/INSTALL.md
+
+First, we will install the golang package and associated libraries. We need, _at minimum_ Go version 1.13 or later. The official Go language packages are distributed as binaries from https://golang.org/dl. For convenience they are also packaged as debian packages distributed through the +apt+ command. You can follow the instructions on https://golang.org/dl or use the apt commands below on a Debian/Ubuntu Linux system:
+
+----
+$ sudo add-apt-repository ppa:longsleep/golang-backports
+$ sudo apt update
+$ sudo apt install golang-go
+----
+
+Check that you have the correct version installed and ready to use by running:
+
+----
+$ go version
+go version go1.13.4 linux/amd64
+----
+
+We have 1.13.4, so we're ready to... Go! Next we need to tell any programs where to find the Go code. This is accomplished with the environment variable +GOPATH+. It doesn't matter where the GOPATH points, as long as you set it consistently. Usually it is located under the current user's home directory (referred to as +~+ in the shell). Set the +GOPATH+ and make sure your shell adds it to your executable +PATH+ like this:
+
+----
+export GOPATH=~/gocode
+export PATH=$PATH:$GOPATH/bin
+----
+
+To avoid having to set these environment variables every time you open a shell, you can add those two lines to the end of your bash shell configuration file +.bashrc+ in your home directory, using the editor of your choice.
+
+==== Copying the LND source code
+
+As with many open source projects nowadays, the source code for LND is on Github. The +go get+ command can fetch it directly using the git protocol:
+
+----
+$ go get -d github.com/lightningnetwork/lnd
+----
+
+Once +git clone+ finishes, you will have a sub-directory under +GOPATH+ that contains the LND source code.
+
+==== Compiling the LND source code
+
+LND uses the +make+ build system for convenience. To build the project, we change directory to LND's source code and then use +make+, like this:
+
+----
+cd $GOPATH/src/github.com/lightningnetwork/lnd
+make && make install
+----
+
+After several minutes, you will have two new commands +lnd+ and +lncli+ installed. Try them out and check their version, to ensure they are installed:
+
+----
+$ lnd --version
+lnd version 0.10.99-beta commit=clock/v1.0.0-106-gc1ef5bb908606343d2636c8cd345169e064bdc91
+$ lncli --version
+lncli version 0.10.99-beta commit=clock/v1.0.0-106-gc1ef5bb908606343d2636c8cd345169e064bdc91
+----
+
+You will likely see a different version from that shown above, as the software continues to evolve long after this book is printed. However, no matter what version you see, the fact that the commands execute and show you version information means that you have succeeded in building the LND software.
 
 === eclair