Git Diff Check

A simple library for checking git diff output for potentially sensitive information

Pre-commit hook

Requires git 2.9+

A pre-commit hook script is provided for convenience that uses this library to test changes before you commit.

• From binary
• From source

From Binary

• For Mac OS

1. Run the installer:

$ curl -L https://raw.githubusercontent.com/ONSdigital/git-diff-check/master/install.sh | sh

• For other platforms

1. Download the latest release for your platform
2. Create (if not already) a folder to store global git hooks (e.g. ${HOME}/.githooks)
3. Unzip the release and place the pre-commit script in the global hooks folder (ensure it's executable)
4. Configure git to use the hooks:

$ git config --global core.hooksPath <path-to-global-hooks-folder>

From Source

(requires Go 1.11+)

$ go get github.com/ONSdigital/git-diff-check
# or ..
$ cd ${GOPATH}
$ git clone https://github.com/ONSdigital/git-diff-check.git src/github.com/ONSdigital/git-diff-check

Then build:

$ cd ${GOPATH}/src/github.com/ONSdigital/git-diff-check
$ go build -o pre-commit cmd/pre-commit/main.go

Then follow the steps in From Binary (other platforms) using your compiled binary in place of a downloaded one

Usage

Once installed, the binary will run each time you use git commit.

If it finds things it thinks could be sensitive it will flag a warning and stop the commit proceeding, e.g.:

$ git add questionableCode.py
$ git commit
Running precommit diff check
WARNING! Potential sensitive data found:
Found in (questionableCode.py)
    > [line] Possible AWS Access Key (line 6)

If you're VERY SURE these files are ok, rerun commit with --no-verify

NB Currently if you update the pre-commit script in your templates, you will need to manually re-copy it into each repo that uses it.

Experimental Entropy Checking

By default, the pre-commit tool won't use entropy checking on patch strings. If you wish to enable this functionality, please set the DC_ENTROPY_EXPERIMENT environment variable.

$ export DC_ENTROPY_EXPERIMENT=1

License

Copyright (c) 2017 Crown Copyright (Office for National Statistics)

Released under MIT license, see LICENSE for details.