The dvc fetch command in DVC (Data Version Control) allows you to download DVC tracked files and directories from a remote repository. It helps you retrieve the data associated with a particular version, making it accessible for local use.
Here’s a more detailed explanation of the dvc fetch command:
- Remote Repository: DVC supports integration with remote storage systems such as Amazon S3, Google Cloud Storage, or a network file system. These remote repositories are typically used to store large datasets or model files.
- Tracking Changes: DVC tracks the changes made to your data files and directories using its version control system. It keeps a record of the data versions and their associated dependencies.
- Data Dependencies: When you create a DVC project, you define the remote storage location where your data files will be stored. DVC ensures that the data files are synchronized between the local workspace and the remote repository.
- Fetching Files: The dvc fetch command allows you to download the data files associated with a specific version from the remote repository. It fetches the files needed to reproduce that version and makes them available in your local workspace.
- Version Identifier: To use dvc fetch, you need to specify the version identifier. This can be a commit hash, a branch name, a tag, or any other valid reference to a version in your DVC project.
- Download Process: When you run dvc fetch, it communicates with the remote repository and downloads the necessary files and directories associated with the specified version. The downloaded files are placed in the appropriate location within your local workspace.
- Updating Cache: Along with fetching the required files, dvc fetch also updates the DVC cache. The cache is a local storage mechanism that allows DVC to efficiently manage and store your data files, preventing redundant downloads.
Here’s an example usage of dvc fetch:
$ dvc fetch --version [version_identifier]
In this example, you need to replace [version_identifier] with the actual version you want to fetch. It could be a commit hash, a branch name, or a tag.
By using dvc fetch, you can easily download the data files associated with a specific version from a remote repository. This allows you to work with different versions of your data locally and reproduce experiments or perform analyses using specific versions of the data.
dvc fetch Command Examples
1. Fetch the latest changes from the default remote upstream repository (if set):
# dvc fetch
2. Fetch changes from a specific remote upstream repository:
# dvc fetch --remote remote_name
3. Fetch the latest changes for a specific target/s:
# dvc fetch target/s
4. Fetch changes for all branch and tags:
# dvc fetch --all-branches --all-tags
5. Fetch changes for all commits:
# dvc fetch --all-commits