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Prerequisites

Before you start, ensure you have an IAM role in your AWS that permits you to create CloudFormation Templates. Latch utilizes CloudFormation Templates to establish an IAM role that enables the configuration and discovery of your S3 buckets.

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Instructions

Important: Latch only supports mounting versioned buckets. To check if your bucket is versioned, open the bucket in S3, go to the Properties tab, and check Bucket Versioning.

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Connecting an AWS Account

1

Go to the 'Data Tab' and click the 'Mount S3 Bucket' button.

2

If you have not connected Latch with your AWS account yet, click the 'Connect AWS Account →' button.

3

Log into the AWS account which contains your buckets.

4

You will be directed to an AWS CloudFormation 'Quick create stack' template.

This template creates an IAM role with:
  • Permission to list all of your buckets,
  • Permission to view or update CORS, versioning, policy, and notification settings only on select buckets you specify,
  • Permission to create, tag, delete, and permission a latch-mount-fw-* Lambda in your account (this Lambda is limited to writing its own CloudWatch logs and forwarding incoming S3 events to SNS, SQS, or Lambda targets), and
  • Permission to execute lambdas and to publish events to LatchBio’s SQS queue (for configuration and bucket notifications, respectively).
The stack also creates a separate “roleReporter” Lambda with no permissions in your account that posts the new role’s ARN back to LatchBio. No permission in the template allows LatchBio to read or configure your account outside of the permitted buckets.When you open the CloudFormation template, you’ll see an acknowledgment stating “The following resource(s) require capabilities: [AWS::IAM::Role]. I acknowledge that AWS CloudFormation might create IAM resources with custom names.” This pertains to you as the customer executing the CloudFormation stack. The role created by the stack has no IAM permissions, but since it needs to be created and it is an IAM role, AWS ensures that you are aware of this action. However, the role itself in the template has the permissions discussed above and no more, which can be verified by inspecting the template in the AWS UI.
5

Specify which buckets you want to give LatchBio access to by entering them as a comma (,) delimited list in the field called 'buckets'.

You can also use wildcards (*) to specify multiple buckets.
6

Click 'Create Stack' and wait for it to be created.

7

Return to Latch Console.

The ‘Mount S3 Bucket’ modal should show your AWS account and all of the buckets you gave LatchBio access to. You might have to click the refresh button on the modal a few times before your buckets show up.
8

Click the 'Mount/Add Link' button for the bucket you want to mount.

The modal will close and the bucket you added will appear in the data list.You can add more buckets by clicking the Add Buckets button - this will allow you to update the Cloudformation stack and give LatchBio access to other buckets in your account.

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Removing a Bucket

Removing a bucket requires edits both on the LatchBio side and in your AWS account.
1

If you have mounted the bucket, hover over the bucket link in the LData homepage, click the ellipsis (…) and select Delete to remove the link.

2

Open the S3 Mount Modal and click 'Add Buckets'.

Remove the bucket from the buckets list and update the Cloudformation stack.
3

In the S3 Console, navigate to the bucket you want to remove > Permissions > scroll to Bucket Policy and remove the entry in 'Statements' called 'latch-data-mount'.

If this is the only entry in the Statements array, you can just delete the bucket policy outright.
4

Still in the bucket homepage, navigate to Properties and scroll to 'Event Notifications' - from here, delete the notification called 'latch-s3-mount'.

If you previously had an event notification for this bucket set up, you’ll have to: 1. Restore that notification, and 2. Go to the Lambda homepage and delete the Lambda called latch-mount-fw-[BUCKET_NAME].Your bucket has now been removed.

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Troubleshooting

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My bucket isn’t showing up in the list in the Mount S3 Bucket modal.

This might be because your bucket isn’t versioned. Latch only supports versioned buckets for mounting. To check if your bucket is versioned, open the bucket in S3, go to the Properties tab, and check Bucket Versioning. If your bucket is versioned and is still not showing up, please reach out to support@latch.bio for assistance.