AWS IoT Rule error action on functions

0

Hello,

I'm using an IoT rule to decode protobuf messages, and having trouble when this fails (e.g., the client has incorrectly packed data). I'm trying to set up an error action that deposits the error information to an S3 bucket, but I do not see any files created.

The smallest reproducible error I can make is this: IoT Rule

{
    "ruleArn": "arn:aws:iot:us-east-1:xxxxxxxx:rule/JMF_Test_Rule",
    "rule": {
        "ruleName": "JMF_Test_Rule",
        "sql": "SELECT decode(*, \"base64\") as payload",
        "description": "",
        "createdAt": "2024-04-26T15:58:53-04:00",
        "actions": [
            {
                "republish": {
                    "roleArn": "arn:aws:iam::xxxxxxx:role/service-role/jmf-test-role-for-republish",
                    "topic": "test/topic/here",
                    "qos": 0
                }
            }
        ],
        "ruleDisabled": false,
        "awsIotSqlVersion": "2016-03-23",
        "errorAction": {
            "s3": {
                "roleArn": "arn:aws:iam::xxxxxxx:role/service-role/jmf-test-s3-error-role",
                "bucketName": "test-bucket-name",
                "key": "my-test-thing.err",
                "cannedAcl": "bucket-owner-full-control"
            }
        }
    }
}

Then, using the MQTT Test Client, I send any text message ("hello world!") to the topic $aws/rules/JMF_Test_Rule (basic ingest). This fails, as I expect, because the incoming data is not valid base64. I know it fails because in CloudWatch I see this:

{
    "timestamp": "2024-04-26 19:59:01.118",
    "logLevel": "ERROR",
    "traceId": "fcb72e63-3297-0556-2b0f-4031a809801c",
    "accountId": "xxxxxxxxx",
    "status": "Failure",
    "eventType": "FunctionExecution",
    "clientId": "iotconsole-79a92762-9ef6-4aba-add1-2be9272c9fbd",
    "topicName": "$aws/rules/JMF_Test_Rule",
    "ruleName": "JMF_Test_Rule",
    "ruleAction": "Decode",
    "resources": {},
    "principalId": "ABCDEF",
    "details": "Invalid parameters. Expected decode(*, $scheme, $[scheme parameters])"
}
{
    "timestamp": "2024-04-26 19:59:01.122",
    "logLevel": "ERROR",
    "traceId": "fcb72e63-3297-0556-2b0f-4031a809801c",
    "accountId": "xxxxxxxxx",
    "status": "Failure",
    "eventType": "RuleExecution",
    "clientId": "iotconsole-79a92762-9ef6-4aba-add1-2be9272c9fbd",
    "topicName": "$aws/rules/JMF_Test_Rule",
    "ruleName": "JMF_Test_Rule",
    "principalId": "ABCDEF",
    "reason": "ExternFunctionException",
    "details": "Function 'Decode' failed to execute for rule 'JMF_Test_Rule'. Invalid parameters. Expected decode(*, $scheme, $[scheme parameters])"
}

However, no files are created in the S3 bucket. I know that the error role has the proper permissions, because if I post valid base64 data, the rule will fail because jmf-test-role-for-republish does not have permissions to publish to test/topic/here, and then an error file is correctly created in the S3 bucket.

Am I doing something wrong on this?

Thank you, Jonathan

1 Answer
0

Hi. Please see here: https://docs.aws.amazon.com/iot/latest/developerguide/rule-error-handling.html

If a problem occurs when activating an action, the rules engine activates an error action, if one is specified for the rule.

In your case, the error is happening in the select statement, before any action is activated.

profile pictureAWS
EXPERT
Greg_B
answered 10 days ago

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