This guide shows how to install and configure bpkg-rep-publish script to update
and publish an archive-based bpkg repository stored in the git repository.
Normally bpkg repository needs to be signed and synchronized to the remote
host that requires authentication. Here we assume that you have sorted out the
password-less repository signing and ssh authentication.

1. Create 'bpub' User

This user will be used to run the bpkg-rep-publish script. We will also use
its home directory to build and install bpkg-rep package, clone the git
repository, create the logs directory, etc.

We create this user with a disabled password so only root will be able to
operate as bpub. Because of this restriction we will allow bpub to run sudo
without a password:

# adduser --disabled-password bpub
# echo "bpub ALL=(ALL) NOPASSWD:ALL" >/etc/sudoers.d/bpub
# chmod 0440 /etc/sudoers.d/bpub

In the rest of this guide commands that start with the $ shell prompt are
expected to be executed as the bpub user and in its home directory (those
that start with # as above are run as root). To change to the bpub user
from root, do:

# su -l bpub


2. Install Prerequisites

a) Install a C++ compiler and git using your distribution's packages.

b) Unless you already have the build2 toolchain installed, download (normally
   from https://download.build2.org) and install build2-toolchain by following
   its INSTALL file instructions. You can build build2-toolchain using bpub's
   login and in its home directory.


3. Build and Install bpkg-rep.

$ mkdir bpkg-rep
$ cd bpkg-rep

$ bpkg create                               \
    cc                                      \
    config.bin.rpath=/home/bpub/install/lib \
    config.install.root=/home/bpub/install

$ bpkg build bpkg-rep,bpkg@https://pkg.cppget.org/1/alpha
$ bpkg install -a

$ cd .. # Back to bpub home.


4. Configure the repository update and synchronization.

Pre-clone the git repository containing the bpkg repository and create the log
directory:

$ git clone https://git.example.org/foo.git
$ mkdir foo.log

Note that the repository contents are expected to be in the foo/1/
subdirectory (see bpkg-rep/publish.in for details).

Perform the initial publish to test the setup and make the subsequent
synchronizations incremental. Here we assume that you may need to additionally
pass some bpkg-rep-create(1) and rsync(1) options to the bpkg-rep-publish
script.

install/bin/bpkg-rep-publish -d example.org:/var/bpkg/1/foo foo ...

Setup publishing as a cron job:

$ crontab -l
MAILTO=publish@example.org
PATH=/usr/local/bin:/bin:/usr/bin
0 * * * * $HOME/install/bin/bpkg-rep-publish -d example.org:/var/bpkg/1/foo --log-dir $HOME/queue.log --lock-timeout 600 $HOME/foo ...