Shallow Repository Cloning

Shallow cloning of a git repository can offer some performance improvement, especially for larger projects with a number of commits, by pulling the smallest number of changes possible. This can either be implemented manually using a custom cloning step or by utilizing an Orb.

To fetch and modify the default checkout step, see this article: How do I modify the checkout step?

Some flags to note that can be added to the git clone <repository> command:

• --depth <depth> will limit the number of commits fetched for the repository or branch being checked out.
• --shallow-since=<date> will do a shallow checkout from the date specified (date should be formatted as YYYY-MM-DD)
• --no-tags prevents git from cloning any tags from the repository (if the installed version of git supports it).

Here is an example:

version: 2.1

jobs:
  build:
    docker:
      - image: circleci/node:latest
    steps:
      - run: git clone --depth 5 "$CIRCLE_REPOSITORY_URL" --branch "$CIRCLE_BRANCH"

You can read more information on Git's website:

• https://git-scm.com/docs/git-clone