Using BFG to Remove Sensitive Data and Text from Git History (with examples)
Introduction
Git is a powerful version control system that allows developers to easily track changes to their codebase over time. However, there may be times when you need to remove certain files or text from your Git history, especially if they contain sensitive information such as passwords or confidential data. The BFG Repo-Cleaner is a tool that can be used to accomplish this task more efficiently than the traditional git-filter-branch command. In this article, we will explore two different use cases of the BFG Repo-Cleaner command, along with their code examples, motivations, explanations, and example outputs.
Use Case 1: Removing a File with Sensitive Data
Code Example
bfg --delete-files file_with_sensitive_data
Motivation
Suppose you accidentally added a file named “credentials.txt” to your Git repository, which contains sensitive information such as passwords or API keys. It is crucial to remove this file from your Git history to prevent unauthorized access to the sensitive data.
Explanation
The --delete-files option is used to specify that we want to remove the specified file from the Git history. In this example, we are removing a file named “file_with_sensitive_data”.
Example Output
...
BFG INFO: Deleted files
- file_with_sensitive_data
BFG INFO: Total BFG commits rewritten: 1
BFG INFO: If the commands ran correctly, the original Git repository should be unchanged (except for some refs BFG modified).
After running the command, BFG will delete the specified file from all commits in the Git history. The output will confirm the deletion of the file, the number of BFG commits rewritten, and the assurance that the original Git repository remains unchanged.
Use Case 2: Removing Text Mentioned in a File from Git History
Code Example
bfg --replace-text path/to/file.txt
Motivation
Imagine that you accidentally committed a file named “database_dump.sql” to your Git repository, which contains sensitive information such as database credentials. Although deleting the file is not enough, as it will still exist in the Git history, it is crucial to remove all occurrences of the sensitive text mentioned in the file to ensure complete data security.
Explanation
With the --replace-text option, BFG allows us to remove all occurrences of the text mentioned in the specified file from the entire Git history. In this example, we are removing text mentioned in a file named “file.txt”.
Example Output
...
BFG INFO: Cleaning commits: 100% (64/64)
BFG INFO: processing path/to/file.txt.old path/to/file.txt
BFG INFO: Removing sensitive data from 64 commits...
BFG INFO: Resetting branch back to parentless state...
BFG INFO: Total BFG commits rewritten: x
BFG INFO: If the commands ran correctly, the original Git repository should be unchanged (except for some refs BFG modified).
The output indicates that BFG is cleaning commits, processing the specified file, removing sensitive data from the commits, resetting the branch, and the number of rewritten BFG commits. As with the previous use case, the original Git repository is expected to remain unchanged except for some references modified by BFG.
Conclusion
In this article, we explored two different use cases of the BFG Repo-Cleaner command: removing a file with sensitive data and removing text mentioned in a file from Git history. We provided code examples, motivations, explanations, and example outputs for each use case. By leveraging the power of BFG, developers can ensure that sensitive information is removed from their Git history, thereby enhancing data security and privacy.
