AWS S3 (HTTP)

In this example, we configure an HTTP connection that publishes twin events to AWS S3 (Simple Storage Service).

Prerequisites

To follow this example you will need:

A Bosch IoT Things service subscription
An AWS S3 bucket
An AWS IAM user with access to S3

Create the connection

Click Go to Dashboard in the row of your Things instance, which will manage the connection.
On the Things dashboard open the tab Connections/Integrations.
Click Create your first connection, or Add in case you have one already.
- Select HTTP from the categories.
- Give the connection a name. Setting a name is required.
- Click the Continue button.

create-http-connection

Configure credentials

Scroll to the Coordinates section.
Choose hmac as the credential type.
Choose aws4-hmac-sha256 as the algorithm.
Enter the AWS region of your S3 bucket, e.g. eu-central-1.
Enter s3 as the AWS service name.
Enter the access key of the S3 user.
Enter the secret key of the S3 user.
Uncheck “Double encode and normalize path segments”.
Choose INCLUDED for Payload hash as header-

aws-s3-coordinates-1

Configure the hostname

Scroll to the Connection coordinates section.
Enter the hostname of your S3 bucket: <bucket-name>.s3.<aws-region>.amazonaws.com

aws-s3-coordinates-2

Add a target

Scroll to the Targets section.
Click the Add target button.
Choose PUT as the HTTP verb.
Enter / as the HTTP path.
Payload mapping will compute the HTTP path for each twin event so that events are stored as distinct objects
Add an authorization subject, e.g. integration:<solution-id>:s3.
Check Thing twin events under Topics to publish on address.
Click Save new target.

aws-s3-target

Configure payload mapping

Scroll to the Payload mapping section.
Check Enable custom JavaScript-based payload mapping.
Change the outgoing payload mapping to compute a unique S3 object name for each event, and set it as the path of the outgoing HTTP request via the special header http.path.
A thing-modified event for the thing com.acme:coffee-brewer of revision 42 would create the S3 object com.acme:coffee-brewer:things:twin:events:modified:42

function mapFromDittoProtocolMsgWrapper(msg) {
  let topic = msg['topic'].split('/').join(':');
  let headers = {
      'http.path': topic + ':' + msg['revision']
  };
  let textPayload = JSON.stringify(msg);
  let bytePayload = null;
  let contentType = 'application/json';

  return Ditto.buildExternalMsg(headers, textPayload, bytePayload, contentType);
}

Click the Create button at the top right to save the connection.

Authorize the connection for twin events

Follow the steps “Create a Hello World thing” and “Add the authorization subject of the connection to the policy” on the Hub-to-Things connection tutorial to authorize the S3 connection to receive twin events.

Remember to use the authorization subject of this connection in the policy, e.g. integration:<solution-id>:s3.

Subsequent twin modifications will create objects in the S3 bucket containing the corresponding events.