How to use the command 'dvc fetch' (with examples)
DVC fetch is a command that allows users to download DVC tracked files and directories from a remote repository. It provides a convenient way to fetch the latest changes and updates from a remote upstream repository.
Use case 1: Fetch the latest changes from the default remote upstream repository
Code:
dvc fetch
Motivation:
When collaborating with a team or working on multiple machines, it is essential to synchronize the latest changes made to a DVC tracked repository. By using the command ‘dvc fetch’ without specifying a remote, it fetches the latest changes from the default remote upstream repository (if set). This ensures that you have the most up-to-date files and directories to work with.
Explanation:
The dvc fetch command without any additional arguments fetches the latest changes from the default remote upstream repository. The default remote can be set using dvc remote default <remote-name>. The command connects to the remote repository and downloads any new or updated data. It does not modify the local workspace, but brings it up to date with the remote repository.
Example Output:
Fetching latest changes from the default remote upstream repository...
Done.
Use case 2: Fetch changes from a specific remote upstream repository
Code:
dvc fetch --remote remote_name
Motivation:
In scenarios where you have multiple remote upstream repositories, it is desirable to obtain changes and updates from a specific one. By using the --remote argument followed by the desired remote name, you can limit the fetch operation to the chosen repository. This allows you to work with different versions of the repository depending on your requirements.
Explanation:
The --remote argument followed by the desired remote name instructs the dvc fetch command to download changes only from that specific remote upstream repository. It ignores the default remote upstream repository. This allows you to fetch updates from a particular repository and have more control over the synchronization process.
Example Output:
Fetching changes from remote repository 'remote_name'...
Done.
Use case 3: Fetch the latest changes for a specific target/s
Code:
dvc fetch target/s
Motivation:
Sometimes, it is necessary to only fetch changes for specific targets, rather than fetching all the files and directories in the repository. By specifying the target/s as arguments, you can limit the fetch operation to those specific files or directories that you want to update.
Explanation:
The target/s argument refers to the specific files or directories you want to fetch changes for. When provided, the dvc fetch command only downloads the latest changes for the specified target/s and updates them in your local workspace. This is useful when you are working on specific files or directories and want to quickly synchronize them with the remote repository.
Example Output:
Fetching latest changes for target 'data/file.txt'...
Done.
Use case 4: Fetch changes for all branch and tags
Code:
dvc fetch --all-branches --all-tags
Motivation:
When you have multiple branches and tags in your DVC tracked repository, it can be tedious to manually fetch changes for each one of them. By using the --all-branches and --all-tags arguments together, you can fetch the changes for all branches and tags in one go. This saves time and effort by automating the fetch process for all branches and tags.
Explanation:
The --all-branches argument instructs the dvc fetch command to fetch changes for all branches in the repository. The --all-tags argument fetches changes for all tags. Combining these two arguments allows you to fetch updates for all branches and tags at once. This is particularly useful when you want to ensure that all branches and tags are up to date with the remote repository.
Example Output:
Fetching changes for all branches and tags...
Done.
Use case 5: Fetch changes for all commits
Code:
dvc fetch --all-commits
Motivation:
In some cases, you may want to fetch changes for all commits made to a DVC tracked repository. This can be useful when you need to examine the changes made in previous commits or when you want to synchronize your local workspace with every commit that has been made. The --all-commits argument allows you to fetch updates for all commits.
Explanation:
The --all-commits argument instructs the dvc fetch command to download changes for all commits made in the remote repository. This means that all changes, even those that are not part of the current branch, will be fetched. It ensures that your local workspace is synchronized with the complete history of commits in the remote repository, providing a comprehensive update.
Example Output:
Fetching changes for all commits...
Done.
Conclusion:
The dvc fetch command is a powerful tool for downloading DVC tracked files and directories from a remote repository. With its various use cases, you can fetch the latest changes from default or specific remote upstream repositories, fetch specific targets, fetch changes for branches and tags, and even fetch changes for all commits. By utilizing dvc fetch, you can easily synchronize your local workspace and stay up to date with the changes made in the remote repository.
