# Git LFS

Managing large files such as audio, video and graphics files has always been one
of the shortcomings of Git. The general recommendation is to not have Git repositories
larger than 1GB to preserve performance.

![Git LFS tracking status](img/lfs-icon.png)

An LFS icon is shown on files tracked by Git LFS to denote if a file is stored
as a blob or as an LFS pointer.

## How it works

Git LFS client talks with the GitLab server over HTTPS. It uses HTTP Basic Authentication
to authorize client requests. Once the request is authorized, Git LFS client receives
instructions from where to fetch or where to push the large file.

## GitLab server configuration

Documentation for GitLab instance administrators is under [LFS administration doc](lfs_administration.md).

## Requirements

- Git LFS is supported in GitLab starting with version 8.2
- Git LFS must be enabled under project settings
- [Git LFS client](https://git-lfs.github.com) version 1.0.1 and up

## Known limitations

- Git LFS v1 original API is not supported since it was deprecated early in LFS
  development
- When SSH is set as a remote, Git LFS objects still go through HTTPS
- Any Git LFS request will ask for HTTPS credentials to be provided so a good Git
  credentials store is recommended
- Git LFS always assumes HTTPS so if you have GitLab server on HTTP you will have
  to add the URL to Git config manually (see [troubleshooting](#troubleshooting))

>**Note**: With 8.12 GitLab added LFS support to SSH. The Git LFS communication
 still goes over HTTP, but now the SSH client passes the correct credentials
 to the Git LFS client, so no action is required by the user.

## Using Git LFS

Lets take a look at the workflow when you need to check large files into your Git
repository with Git LFS. For example, if you want to upload a very large file and
check it into your Git repository:

```bash
git clone git@gitlab.example.com:group/project.git
git lfs install                       # initialize the Git LFS project
git lfs track "*.iso"                 # select the file extensions that you want to treat as large files
```

Once a certain file extension is marked for tracking as a LFS object you can use
Git as usual without having to redo the command to track a file with the same extension:

```bash
cp ~/tmp/debian.iso ./                # copy a large file into the current directory
git add .                             # add the large file to the project
git commit -am "Added Debian iso"     # commit the file meta data
git push origin master                # sync the git repo and large file to the GitLab server
```

> **Note**: Make sure that `.gitattributes` is tracked by git. Otherwise Git
> LFS will not be working properly for people cloning the project.
>
> ```bash
> git add .gitattributes
> ```

Cloning the repository works the same as before. Git automatically detects the
LFS-tracked files and clones them via HTTP. If you performed the git clone
command with a SSH URL, you have to enter your GitLab credentials for HTTP
authentication.

```bash
git clone git@gitlab.example.com:group/project.git
```

If you already cloned the repository and you want to get the latest LFS object
that are on the remote repository, eg. for a branch from origin:

```bash
git lfs fetch origin master
```

## File Locking

> [Introduced](https://gitlab.com/gitlab-org/gitlab-ce/issues/35856) in GitLab 10.5.

The first thing to do before using File Locking is to tell Git LFS which
kind of files are lockable. The following command will store PNG files
in LFS and flag them as lockable:

```bash
git lfs track "*.png" --lockable
```

After executing the above command a file named `.gitattributes` will be
created or updated with the following content:

```bash
*.png filter=lfs diff=lfs merge=lfs -text lockable
```

You can also register a file type as lockable without using LFS
(In order to be able to lock/unlock a file you need a remote server that implements the  LFS File Locking API),
in order to do that you can edit the `.gitattributes` file manually:

```bash
*.pdf lockable
```

After a file type has been registered as lockable, Git LFS will make
them readonly on the file system automatically. This means you will
need to lock the file before editing it.

### Managing Locked Files

Once you're ready to edit your file you need to lock it first:

```bash
git lfs lock images/banner.png
Locked images/banner.png
```

This will register the file as locked in your name on the server:

```bash
git lfs locks
images/banner.png  joe   ID:123
```

Once you have pushed your changes, you can unlock the file so others can
also edit it:

```bash
git lfs unlock images/banner.png
```

You can also unlock by id:

```bash
git lfs unlock --id=123
```

If for some reason you need to unlock a file that was not locked by you,
you can use the `--force` flag as long as you have a `maintainer` access on
the project:

```bash
git lfs unlock --id=123 --force
```

## Troubleshooting

### error: Repository or object not found

There are a couple of reasons why this error can occur:

- You don't have permissions to access certain LFS object

Check if you have permissions to push to the project or fetch from the project.

- Project is not allowed to access the LFS object

LFS object you are trying to push to the project or fetch from the project is not
available to the project anymore. Probably the object was removed from the server.

- Local git repository is using deprecated LFS API

### Invalid status for `<url>` : 501

Git LFS will log the failures into a log file.
To view this log file, while in project directory:

```bash
git lfs logs last
```

If the status `error 501` is shown, it is because:

- Git LFS is not enabled in project settings. Check your project settings and
  enable Git LFS.

- Git LFS support is not enabled on the GitLab server. Check with your GitLab
  administrator why Git LFS is not enabled on the server. See
  [LFS administration documentation](lfs_administration.md) for instructions
  on how to enable LFS support.

- Git LFS client version is not supported by GitLab server. Check your Git LFS
  version with `git lfs version`. Check the Git config of the project for traces
  of deprecated API with `git lfs -l`. If `batch = false` is set in the config,
  remove the line and try to update your Git LFS client. Only version 1.0.1 and
  newer are supported.

### getsockopt: connection refused

If you push a LFS object to a project and you receive an error similar to:
`Post <URL>/info/lfs/objects/batch: dial tcp IP: getsockopt: connection refused`,
the LFS client is trying to reach GitLab through HTTPS. However, your GitLab
instance is being served on HTTP.

This behaviour is caused by Git LFS using HTTPS connections by default when a
`lfsurl` is not set in the Git config.

To prevent this from happening, set the lfs url in project Git config:

```bash
git config --add lfs.url "http://gitlab.example.com/group/project.git/info/lfs"
```

### Credentials are always required when pushing an object

>**Note**: With 8.12 GitLab added LFS support to SSH. The Git LFS communication
 still goes over HTTP, but now the SSH client passes the correct credentials
 to the Git LFS client, so no action is required by the user.

Given that Git LFS uses HTTP Basic Authentication to authenticate the user pushing
the LFS object on every push for every object, user HTTPS credentials are required.

By default, Git has support for remembering the credentials for each repository
you use. This is described in [Git credentials man pages](https://git-scm.com/docs/gitcredentials).

For example, you can tell Git to remember the password for a period of time in
which you expect to push the objects:

```bash
git config --global credential.helper 'cache --timeout=3600'
```

This will remember the credentials for an hour after which Git operations will
require re-authentication.

If you are using OS X you can use `osxkeychain` to store and encrypt your credentials.
For Windows, you can use `wincred` or Microsoft's [Git Credential Manager for Windows](https://github.com/Microsoft/Git-Credential-Manager-for-Windows/releases).

More details about various methods of storing the user credentials can be found
on [Git Credential Storage documentation](https://git-scm.com/book/en/v2/Git-Tools-Credential-Storage).

### LFS objects are missing on push

GitLab checks files to detect LFS pointers on push. If LFS pointers are detected, GitLab tries to verify that those files already exist in LFS on GitLab.

Verify that LFS in installed locally and consider a manual push with `git lfs push --all`.

If you are storing LFS files outside of GitLab you can disable LFS on the project by setting `lfs_enabled: false` with the [projects api](../../api/projects.md#edit-project).

### Hosting LFS objects externally

It is possible to host LFS objects externally by setting a custom LFS url with `git config -f .lfsconfig lfs.url https://example.com/<project>.git/info/lfs`.

You might choose to do this if you are using an appliance like a Sonatype Nexus to store LFS data. If you choose to use an external LFS store, 
GitLab will not be able to verify LFS objects which means that pushes will fail if you have GitLab LFS support enabled.

To stop push failure, LFS support can be disabled in the [Project settings](../../user/project/settings/index.md). This means you will lose GitLab LFS value-adds (Verifying LFS objects, UI integration for LFS).
