Chef Diff

Intro

Chef Diff is a library for calculating what Chef objects where modified between two revisions in Chef Git repo. Chef Diff is a derivative/extension of Between Meals.

Chef Diff calculates changes for nodes, clients, users, environments, databags, roles, environment-specific roles and cookbooks between revisions in a Chef repo.

Chef Diff allows subdirs in nodes, clients and environments to enable the Chef repo layout to match a clustered multi Chef server infrastructure.

Environment-specific roles (roles_local)

In addition to the standard roles/ directory, Chef Diff supports a second roles directory for environment-specific role overrides. By convention this directory is called roles_local/, and subdirectories within it are part of the role name — for example roles_local/cluster/web.json is reported as the role cluster/web.

This is useful when running a multi-environment or multi-cluster Chef setup where some roles differ per environment but you do not want to pollute the shared roles/ tree.

When using Chef Diff as a library, pass role_local_dir to Changeset.new:

changeset = ChefDiff::Changeset.new(
  logger, repo, start_ref, end_ref,
  role_dir:       'roles',
  role_local_dir: 'roles_local',   # default used by chef-diff binary
  # … other dirs …
)
changeset.roles_local  # => array of ChefDiff::Changes::RoleLocal objects

The chef-diff binary uses roles_local as the default directory name and reports changes under the heading Roles_local changed:.

Usage

Cheff Diff is mainly intended to be used as a gem by other tools but provides a commandline inspection tool:

$ chef-diff
Usage: chef-diff [options] <repo_path>
    -v, --verbose                    Run verbosely
    -s, --start_ref REF              Git start reference
    -e, --end_ref REF                Git end reference (default HEAD)

SVN support

Chef Diff includes an SVN backend (ChefDiff::Repo::Svn) inherited from Between Meals. It is experimental and untested — there are no specs for it and it has not been validated against a real SVN repository. Use at your own risk.

Dependencies

• JSON
• Mixlib::ShellOut

Testing

docker run --rm -v "$(pwd)":/app -w /app ruby:3.3 \
  sh -c "bundle install && bundle exec rake"