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Calling AWS APIs

If you are using a dedicated device cloud running in your AWS account, Ioto provides a convenience wrapper to make invoking AWS APIs using REST easier.

Without this wrapper, invoking AWS APIs requires using either the bulky AWS C SDK or manually using the AWS SigV4 REST API which is tedious at best.

The Ioto AWS API wrapper uses the SigV4 API but performs the SigV4 signing for you.

Requirements

To use the AWS SigV4 API, you need to have AWS IAM access keys enabled in the device. See the section on AWS IAM Access Keys for details.

API Quick Tour

To issue an AWS REST API, use the aws API:

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Url *up = urlAlloc();
int status = aws(up, "us-east-1", "logs", "Logs_20140328.PutLogEvents", data, dataLen, NULL);

This will issue a request to the specified AWS service (logs) in a region (us-east-1) and invoke the targeted service (Logs_20140328.PutLogEvents). This call will upload log data to CloudWatch logs.

Under the hood, the aws API is calling awsSign and urlFetch.

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char *signedHeaders = awsSign(region, service, target, "POST", "", NULL, body, bodyLen, headers);
char *url = sfmt("https://%s.%s.amazonaws.com/", service, region);
int status = urlFetch(up, "POST", url, body, bodyLen, signedHeaders);

The awsSign API will perform the required cryptographic signing of a request to be received by AWS.