A `VolumeAttributesClass` with `driverName: git.liken.sh` carries a
commit and push policy in `parameters`. Every parameter has a default,
so an empty class arms a volume with the defaults. The controller
refuses a class with an unknown or malformed parameter, naming the
first bad one.

| Parameter | Values | Default |
|---|---|---|
| `push.quiesce` | A Go duration, at least `5s`. The driver commits and pushes after the tree has been quiet this long. | `30s` |
| `push.maxLatency` | A Go duration, at least `push.quiesce`, or `never`. The driver pushes when the oldest unpushed commit is this old, whatever the tree is doing. | `5m`, or `push.quiesce` when that is longer |
| `commit.maxFileSize` | A Kubernetes quantity such as `1Mi`, or `0` for no limit. A larger file is not committed and is named in the events and the log. | `1Mi` |
| `commit.author` | `Name <email>`. The author and committer of every commit. | `git-csi-driver <git-csi-driver@liken.sh>` |
| `ignore` | Comma-separated `.gitignore` patterns, added to the repository's own. | empty |
| `metadata` | `true` or `false`. Whether modes, owners, and empty directories are recorded on `refs/git-csi/metadata` and replayed at restore. | `true` |

## Events

| Reason | When |
|---|---|
| `GitVolumeArmed` | The claim named a class of this driver. |
| `GitVolumeUnarmed` | The claim names no class of this driver. |
| `GitVolumePending` | The tree holds paths the driver has not committed. Posted when the set first becomes non-empty. |
| `GitVolumePushed` | A push succeeded, with the commit and the count of paths. |
| `GitVolumePushFailed` | A push failed, with git's error. |
| `GitVolumeFileSkipped` | A file over `commit.maxFileSize` was left out of a commit. |
| `GitVolumeDiverged` | The volume moved to its side branch, after a rejected push or an aborted rebase. |
| `GitVolumeHealed` | Upstream took the side branch's work, and the volume is back on its ref. |
| `GitVolumeSwept` | The sweep removed a work tree nothing had staged for `--sweep-after`. |

## The abnormal gauge

`git_csi_volume_abnormal`, labeled `namespace` and `volume`, is one for
an unarmed volume with pending paths, a failed push, a skipped file, an
unpushed commit older than `push.maxLatency`, an invalid class, a ref
that moved upstream while the tree held uncommitted writes, a diverged
volume, a ref the remote no longer holds, and an abandoned work tree of
the same repository on the node. The driver's log says which.

## Metrics

Each gauge is labeled `namespace` and `claim`.

| Metric | Meaning |
|---|---|
| `git_csi_armed` | One when a class of this driver arms the volume. |
| `git_csi_pending_paths` | Paths the last scan found that the driver has not committed. |
| `git_csi_unpushed_commits` | Commits not yet on the remote. |
| `git_csi_last_push_timestamp_seconds` | When the last push succeeded. |
| `git_csi_push_failures_total` | Pushes that failed. |
| `git_csi_skipped_files` | Files over `commit.maxFileSize` in the tree. |
| `git_csi_diverged` | One while the volume pushes to its side branch. |
| `git_csi_volume_abnormal` | One while anything above is wrong. Labeled `namespace` and `volume`, not claim. |