An implementation of the `storagedriver.StorageDriver` interface which uses Google Cloud for object storage.
## Parameters
<table>
<tr>
<th>Parameter</th>
<th>Required</th>
<th>Description</th>
</tr>
<tr>
<td>
<code>bucket</code>
</td>
<td>
yes
</td>
<td>
Storage bucket name.
</td>
</tr>
<tr>
<td>
<code>keyfile</code>
</td>
<td>
no
</td>
<td>
A private service account key file in JSON format. Instead of a key file <ahref="https://developers.google.com/identity/protocols/application-default-credentials">Google Application Default Credentials</a> can be used.
</td>
</tr>
<tr>
<td>
<code>rootdirectory</code>
</td>
<td>
no
</td>
<td>
This is a prefix that will be applied to all Google Cloud Storage keys to allow you to segment data in your bucket if necessary.
</tr>
</tr>
<tr>
<td>
<code>chunksize</code>
</td>
<td>
no (default 5242880)
</td>
<td>
This is the chunk size used for uploading large blobs, must be a multiple of 256*1024.
</tr>
</table>
`bucket`: The name of your Google Cloud Storage bucket where you wish to store objects (needs to already be created prior to driver initialization).
`keyfile`: (optional) A private key file in JSON format, used for [Service Account Authentication](https://cloud.google.com/storage/docs/authentication#service_accounts).
**Note** Instead of a key file you can use [Google Application Default Credentials](https://developers.google.com/identity/protocols/application-default-credentials).
`rootdirectory`: (optional) The root directory tree in which all registry files will be stored. Defaults to the empty string (bucket root).
