update-from-github

#!/bin/bash
## ============================================================================
## File name   : update-from-github
## Description : Script to update local files to match a given remote git branch
## Author(s)   : Michael Hucka <mhucka@caltech.edu>
## Organization: California Institute of Technology
## Date created: 2019-03-19
#
# This checks a remote git repostiory for changes to a git repository, and if it
# detects that the remote is ahead of the local copy, it does a git rebase to
# synchronize the local copy with the remote.  The script takes an optional
# argument: the branch to compare against.  (The default is master.)
#
# To make it possible to clone the github repo, the repo must be public and
# the protocol used to create the initial git clone must be https instead of
# git (or else you will get permission denied errors when this script runs).
#
# Don't forget to do the first clone of the repo using --recursive!
#
# This is intended to be run from cron or a similar system daemon control
# system (e.g., Jenkins).  Here's an example of a cron entry:
#
#   */5 * * * * /home/hugo/sbml/admin/update-from-github >> /var/log/hugo/github-updates.log 2>&1
#
# If you want to update a branch, pass the branch name as an argument. For
# example, if you want to keep the branch 'develop' updated in a local repo
# instead of defaulting to 'master', you could do this:
#
#   */5 * * * * /home/hugo/sbml/admin/update-from-github develop >> /var/log/hugo/github-updates.log 2>&1
#
# Assumptions for purposes of the SBML.org site repository:
# - this script is located in the local repository copy
# - permissions on this script and other things are set up properly
# -----------------------------------------------------------------------------

echo "===== ${0##*/} started at $(/bin/date '+%G-%m-%d:%H%M') ====="

# Because this is run from cron, we may need to include /usr/local/bin/.

PATH=/usr/local/bin:/opt/local/bin:/bin:/usr/bin

# Change to the directory where this file is located.  This is so that it
# works from cron.

cd $(dirname "${BASH_SOURCE[0]}") > /dev/null 2>&1

# Get the path of our local repo, based on the assumption that this file is
# located somewhere in the repo itself.

root=$(git rev-parse --show-toplevel)
cd $root

# Does the remote origin have any changes we don't have on this branch?

git remote update
branch=$(git rev-parse --abbrev-ref HEAD)
changes=$(git rev-list HEAD...origin/$branch --count)

if (( $changes > 0 )); then
    echo "Remote branch $branch has changes. Pulling them & updating site.toml"

    # This is a sledgehammer, but past efforts at being smarter failed, and
    # I'm just tired, so tired, of git.
    git stash
    git pull --rebase origin ${1}
    retval=$?

    # Update the site version data file.
    versionfile=$root/site/data/site.toml

    count=$(git rev-list HEAD --count)
    identifier=$(git describe --always --tags --dirty="-local")
    timestamp=$(git log -1 --date=format:"%Y-%m-%d %T" --format="%ai")

    cat <<EOF > $versionfile
# =============================================================================
# File name   : /data/site.toml
# Description : Data file for site data
#
#   ╭────────────────────── Notice ── Notice ── Notice ──────────────────────╮
#   │                                                                        │
#   │                          Do not edit this file.                        │
#   │                                                                        │
#   │                THIS FILE IS AUTOMATICALLY REGENERATED.                 │
#   │                                                                        │
#   ╰────────────────────── Notice ── Notice ── Notice ──────────────────────╯
#
# This file was automatically generated by admin/update-from-github.
#
# =============================================================================

commit_count = "$count"
identifier = "$identifier"
revision = "$count ($identifier on branch $branch)"
timestamp = "$timestamp"
EOF
else
    echo "No changes"
fi

# Done.

echo "===== ${0##*/} stopped at $(/bin/date '+%G-%m-%d:%H%M') ====="
exit $retval