Git_tree

This Ruby gem installs 3 commands that scan a git directory tree; 2 of the commands write out scripts and the third executes an arbitrary bash command for each repository. Directories containing a file called .ignore are ignored.

• The git-tree-replicate command writes a script that clones the repos in the tree, and adds any defined remotes.

  • Any git repos that have already been cloned into the target directory tree are skipped. This means you can rerun git-tree-replicate as many times as you want, without ill effects.
  • All remotes in each repo are replicated.

• The git-tree-evars command writes a script that defines environment variables pointing to git repos.

• The git-tree-exec command executes an arbitrary bash command for each repository.

All commands require one environment variable reference to be passed to them. Enclose the name of the environment variable within single quotes, which will prevent the shell from expanding it before invoking the command.

The following creates a script in the current directory called work.sh, that replicates the desired portions of the directory tree of git repos pointed to by $work:

$ git-tree-replicate '$work' > work.sh

The generated environment variables will all be relative to the path pointed to by the expanded environment variable that you provided. You will understand what this means once you look at the generated script.

When git-tree-replicate completes, edit the generated script to suit, then copy it to the target machine and run it. The following example copies the script to machine2 and runs it:

$ scp work.sh machine2:

$ ssh machine2 work.sh

Following is a sample of one section, which is repeated for every git repo that is processed: You can edit them to suit.

if [ ! -d "sinatra/sinatras-skeleton/.git" ]; then
  mkdir -p 'sinatra'
  pushd 'sinatra' > /dev/null
  git clone git@github.com:mslinn/sinatras-skeleton.git
  git remote add upstream 'https://github.com/simonneutert/sinatras-skeleton.git'
  popd > /dev/null
fi

The git-tree-evars command should be run on the target computer. The command requires only one parameter: an environment variable reference, pointing to the top-level directory to replicate. The environment variable reference must be contained within single quotes to prevent expansion by the shell.

The following appends to any script in the $work directory called .evars. The script defines environment variables that point to each git repos pointed to by $work:

$ git-tree-evars '$work' >> $work/.evars

Following is a sample of environment variable definitions. You are expected to edit it to suit.

export work=/mnt/c/work
export ancientWarmth=$work/ancientWarmth/ancientWarmth
export ancientWarmthBackend=$work/ancientWarmth/ancientWarmthBackend
export braintreeTutorial=$work/ancientWarmth/braintreeTutorial
export survey_analytics=$work/ancientWarmth/survey-analytics
export survey_creator=$work/ancientWarmth/survey-creator
export django=$work/django/django
export frobshop=$work/django/frobshop

The environment variable definitions are meant to be saved into a file that is sourced upon boot. While you could place them in a file like ~/.bashrc, the author's preference is to instead place them in $work/.evars, and add the following to ~/.bashrc:

source "$work/.evars"

Thus each time you log in, the environment variable definitions will have been re-established. You can therefore change directory to any of the cloned projects, like this:

$ cd $git_root

$ cd $my_project

The git-tree-exec command can be run on any computer. The command requires two parameters. The first parameter indicates the directory or directories to process. 3 forms are accepted:

1. A directory name, which may be relative or absolute.
2. An environment variable reference, which must be contained within single quotes to prevent expansion by the shell.
3. A list of directory names, which may be relative or absolute, and may contain environment variables.

For all subdirectories of current directory, update Gemfile.lock and install a local copy of the gem:

$ git-tree-exec '
  $jekyll_plugin_logger
  $jekyll_draft
  $jekyll_plugin_support
  $jekyll_all_collections
  $jekyll_plugin_template
  $jekyll_flexible_include_plugin
  $jekyll_href
  $jekyll_img
  $jekyll_outline
  $jekyll_plugin_template
  $jekyll_pre
  $jekyll_quote
' 'bundle && bundle update && rake install'

This example shows how to display the version of projects that create gems under the directory pointed to by $my_plugins.

An executable script is required on the PATH, so git-tree-exec can invoke it as it loops through the subdirectories. I call this script version, and it is written in bash, although the language used is not significant:

#!/bin/bash

x="$( ls lib/**/version.rb 2> /dev/null )"
if [ -f "$x" ]; then
  v="$(
    cat "$x" | \
    grep '=' | \
    sed -e s/.freeze// | \
    tr -d 'VERSION =\"' | \
    tr -d \'
  )"
  echo "$(basename $PWD) v$v"
fi

Call it like this:

$ git-tree-exec '$my_plugins' version
jekyll_all_collections v0.3.3
jekyll_archive_create v1.0.2
jekyll_archive_display v1.0.1
jekyll_auto_redirect v0.1.0
jekyll_basename_dirname v1.0.3
jekyll_begin_end v1.0.1
jekyll_bootstrap5_tabs v1.1.2
jekyll_context_inspector v1.0.1
jekyll_download_link v1.0.1
jekyll_draft v1.1.2
jekyll_flexible_include_plugin v2.0.20
jekyll_from_to_until v1.0.3
jekyll_href v1.2.5
jekyll_img v0.1.5
jekyll_nth v1.1.0
jekyll_outline v1.2.0
jekyll_pdf v0.1.0
jekyll_plugin_logger v2.1.1
jekyll_plugin_support v0.7.0
jekyll_plugin_template v0.3.0
jekyll_pre v1.4.1
jekyll_quote v0.4.0
jekyll_random_hex v1.0.0
jekyll_reading_time v1.0.0
jekyll_revision v0.1.0
jekyll_run v1.0.1
jekyll_site_inspector v1.0.0
jekyll_sort_natural v1.0.0
jekyll_time_since v0.1.3

List the projects under the directory pointed to by $my_plugins that have a demo/ subdirectory:

$ git-tree-exec '$my_plugins' \
  'if [ -d demo ]; then realpath demo; fi'
/mnt/c/work/jekyll/my_plugins/jekyll-hello/demo
/mnt/c/work/jekyll/my_plugins/jekyll_all_collections/demo
/mnt/c/work/jekyll/my_plugins/jekyll_archive_create/demo
/mnt/c/work/jekyll/my_plugins/jekyll_download_link/demo
/mnt/c/work/jekyll/my_plugins/jekyll_draft/demo
/mnt/c/work/jekyll/my_plugins/jekyll_flexible_include_plugin/demo
/mnt/c/work/jekyll/my_plugins/jekyll_from_to_until/demo
/mnt/c/work/jekyll/my_plugins/jekyll_href/demo
/mnt/c/work/jekyll/my_plugins/jekyll_img/demo
/mnt/c/work/jekyll/my_plugins/jekyll_outline/demo
/mnt/c/work/jekyll/my_plugins/jekyll_pdf/demo
/mnt/c/work/jekyll/my_plugins/jekyll_plugin_support/demo
/mnt/c/work/jekyll/my_plugins/jekyll_plugin_template/demo
/mnt/c/work/jekyll/my_plugins/jekyll_pre/demo
/mnt/c/work/jekyll/my_plugins/jekyll_quote/demo
/mnt/c/work/jekyll/my_plugins/jekyll_revision/demo
/mnt/c/work/jekyll/my_plugins/jekyll_time_since/demo

Type the following at a shell prompt on the machine you are copying the git tree from, and on the machine that you are copying the git tree to:

$ yes | sudo apt install cmake libgit2-dev libssh2-1-dev pkg-config

$ gem install git_tree

To register the new commands, either log out and log back in, or open a new console.

More information is available on Mike Slinn’s website

After checking out the repo, run bin/setup to install dependencies.

Run the following to create a directory tree for testing.

$ ruby bin/make_test_directory.rb

You can run bin/console for an interactive prompt that will allow you to experiment.

$ bin/console
irb(main):001:0> GitTree.command_replicate 'demo'

irb(main):002:0> GitTree.command_evars 'demo'

To build and install this gem onto your local machine, run:

$ bundle exec rake install

Examine the newly built gem:

$ gem info git_tree

*** LOCAL GEMS ***
git_tree (0.2.0)
    Author: Mike Slinn
    Homepage:
    https://github.com/mslinn/git_tree_replicate
    License: MIT
    Installed at: /home/mslinn/.gems

To release a new version:

1. Update the version number in version.rb.

2. Commit all changes to git; if you don't the next step might fail with an unexplainable error message.

3. Run the following:

   $ bundle exec rake release

   The above creates a git tag for the version, commits the created tag, and pushes the new .gem file to RubyGems.org.

1. Fork the project
2. Create a descriptively named feature branch
3. Add your feature
4. Submit a pull request

The gem is available as open source under the terms of the MIT License.