Rclone

You must generate an Access Key before getting started. All examples will utilize access_key_id and access_key_secret variables which represent the Access Key ID and Secret Access Key values you generated.

Rclone is a command-line tool which manages files on cloud storage. You can use rclone to upload objects to R2 concurrently.

Configure rclone

With rclone ↗ installed, you may run rclone config ↗ to configure a new S3 storage provider. You will be prompted with a series of questions for the new provider details.

Recommendation

It is recommended that you choose a unique provider name and then rely on all default answers to the prompts.

This will create a rclone configuration file, which you can then modify with the preset configuration given below.

1. Create new remote by selecting n.
2. Select a name for the new remote. For example, use r2.
3. Select the Amazon S3 Compliant Storage Providers storage type.
4. Select Cloudflare R2 storage for the provider.
5. Select whether you would like to enter AWS credentials manually, or get it from the runtime environment.
6. Enter the AWS Access Key ID.
7. Enter AWS Secret Access Key (password).
8. Select the region to connect to (optional).
9. Select the S3 API endpoint.

Note

Ensure you are running rclone v1.59 or greater (rclone downloads ↗). Versions prior to v1.59 may return HTTP 401: Unauthorized errors, as earlier versions of rclone do not strictly align to the S3 specification in all cases.

Edit an existing rclone configuration

If you have already configured rclone in the past, you may run rclone config file to print the location of your rclone configuration file:

rclone config file
# Configuration file is stored at:
# ~/.config/rclone/rclone.conf

Then use an editor (nano or vim, for example) to add or edit the new provider. This example assumes you are adding a new r2 provider:

[r2]
type = s3
provider = Cloudflare
access_key_id = abc123
secret_access_key = xyz456
endpoint = https://<accountid>.r2.cloudflarestorage.com
acl = private

Note

If you are using a token with Object-level permissions, you will need to add no_check_bucket = true to the configuration to avoid errors.

You may then use the new rclone provider for any of your normal workflows.

List buckets & objects

The rclone tree ↗ command can be used to list the contents of the remote, in this case Cloudflare R2.

rclone tree r2:
# /
# ├── user-uploads
# │   └── foobar.png
# └── my-bucket-name
#     ├── cat.png
#     └── todos.txt

rclone tree r2:my-bucket-name
# /
# ├── cat.png
# └── todos.txt

Upload and retrieve objects

The rclone copy ↗ command can be used to upload objects to an R2 bucket and vice versa - this allows you to upload files up to the 5 TB maximum object size that R2 supports.

# Upload dog.txt to the user-uploads bucket
rclone copy dog.txt r2:user-uploads/
rclone tree r2:user-uploads
# /
# ├── foobar.png
# └── dog.txt

# Download dog.txt from the user-uploads bucket
rclone copy r2:user-uploads/dog.txt .

A note about multipart upload part sizes

For multipart uploads, part sizes can significantly affect the number of Class A operations that are used, which can alter how much you end up being charged. Every part upload counts as a separate operation, so larger part sizes will use fewer operations, but might be costly to retry if the upload fails. Also consider that a multipart upload is always going to consume at least 3 times as many operations as a single PutObject, because it will include at least one CreateMultipartUpload, UploadPart & CompleteMultipartUpload operations.

Balancing part size depends heavily on your use-case, but these factors can help you minimize your bill, so they are worth thinking about.

You can configure rclone's multipart upload part size using the --s3-chunk-size CLI argument. Note that you might also have to adjust the --s3-upload-cutoff argument to ensure that rclone is using multipart uploads. Both of these can be set in your configuration file as well. Generally, --s3-upload-cutoff will be no less than --s3-chunk-size.

rclone copy long-video.mp4 r2:user-uploads/ --s3-upload-cutoff=100M --s3-chunk-size=100M

Generate presigned URLs

You can also generate presigned links which allow you to share public access to a file temporarily using the rclone link ↗ command.

# You can pass the --expire flag to determine how long the presigned link is valid. The --unlink flag isn't supported by R2.
rclone link r2:my-bucket-name/cat.png --expire 3600
# https://<accountid>.r2.cloudflarestorage.com/my-bucket-name/cat.png?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=<credential>&X-Amz-Date=<timestamp>&X-Amz-Expires=3600&X-Amz-SignedHeaders=host&X-Amz-Signature=<signature>