Common AWS IoT Events issues and solutions - AWS IoT Events
Detector model creation errors Updates from a deleted detector model Action trigger failure (when meeting a condition) Action trigger failure (when breeching a threshold) Incorrect state usage Connection messageInvalidRequestException message Amazon CloudWatch Logs action.setTimer errorsAmazon CloudWatch payload errorsIncompatible data typesFailed to send message to AWS IoT Events

Common AWS IoT Events issues and solutions

See the following section to troubleshoot errors and find possible solutions to resolve issues with AWS IoT Events.

Detector model creation errors

I get errors when I attempt to create a detector model.

When you create a detector model, you must consider the following limitations.

  • Only one action is allowed in each action field.

  • The condition is required for transitionEvents. It's optional for OnEnter, OnInput, and OnExit events.

  • If the condition field is empty, the evaluated result of the condition expression is equivalent to true.

  • The evaluated result of the condition expression should be a Boolean value. If the result isn't a Boolean value, it's equivalent to false and doesn't trigger the actions or transition to the nextState specified in the event.

For more information, see AWS IoT Events detector model restrictions and limitations.

Updates from a deleted detector model

I updated or deleted a detector model a few minutes ago but I'm still getting state updates from the old detector model through MQTT messages or SNS alerts.

If you update, delete, or recreate a detector model (see UpdateDetectorModel), there is a delay before all detector instances are deleted and the new model is used. During this time, inputs might continue to be processed by the instances of the previous version of the detector model. You might continue to receive alerts defined by the previous detector model. Wait for at least seven minutes before you recheck the update or report an error.

Action trigger failure (when meeting a condition)

The detector fails to trigger an action or transition to a new state when the condition is met.

Verify that the evaluated result of the detector's conditional expression is a Boolean value. If the result isn't a Boolean value, it's equivalent to false and doesn't trigger the action or transition to the nextState specified in the event. For more information, see Conditional expression syntax.

Action trigger failure (when breeching a threshold)

The detector doesn't trigger an action or an event transition when the variable in a conditional expression reaches a specified value.

If you update setVariable for onInput, onEnter, or onExit, the new value isn't used when evaluating any condition during the current processing cycle. Instead, the original value is used until the current cycle is complete. You can change this behavior by setting the evaluationMethod parameter in the detector model definition. When evaluationMethod is set to SERIAL, variables are updated and event conditions evaluated in the order that the events are defined. When evaluationMethod is set to BATCH (the default), variables are updated and events performed only after all event conditions are evaluated.

Incorrect state usage

The detector enters the wrong states when I attempt to send messages to inputs by using BatchPutMessage.

If you use BatchPutMessage to send multiple messages to inputs, the order in which the messages or inputs are processed isn't guaranteed. To guarantee ordering, send messages one at time and wait each time for BatchPutMessage to acknowledge success.

Connection message

I get a ('Connection aborted.', error(54, 'Connection reset by peer')) error when I attempt to call or invoke an API.

Verify that OpenSSL uses TLS 1.1 or a later version to establish the connection. This should be the default under most Linux distributions or Windows version 7 and later. Users of macOS might need to upgrade OpenSSL.

InvalidRequestException message

I get InvalidRequestException when I attempt to call CreateDetectorModel and UpdateDetectorModel APIs.

Check the following to help resolve the issue. For more information, see CreateDetectorModel and UpdateDetectorModel.

  • Make sure that you don't use both seconds and durationExpression as the parameters of SetTimerAction at the same time.

  • Make sure that your string expression for durationExpression is valid. The string expression can contain numbers, variables ($variable.<variable-name>), or input values ($input.<input-name>.<path-to-datum>).

Amazon CloudWatch Logs action.setTimer errors

You can set up Amazon CloudWatch Logs to monitor AWS IoT Events detector model instances. The following are common errors generated by AWS IoT Events, when you use action.setTimer.

  • Error: Your duration expression for the timer named <timer-name> could not be evaluated to a number.

    Make sure that your string expression for durationExpression can be converted to a number. Other data types, such as Boolean, aren't allowed.

  • Error: The evaluated result of your duration expression for the timer named <timer-name> is greater than 31622440. To ensure accuracy, make sure that your duration expression refers to a value between 60‐31622400.

    Make sure that the duration of your timer is less than or equal to 31622400 seconds. The evaluated result of the duration is rounded down to the nearest whole number.

  • Error: The evaluated result of your duration expression for the timer named <timer-name> is less than 60. To ensure accuracy, make sure that your duration expression refers to a value between 60‐31622400.

    Make sure that the duration of your timer is greater than or equal to 60 seconds. The evaluated result of the duration is rounded down to the nearest whole number.

  • Error: Your duration expression for the timer named <timer-name> could not be evaluated. Check the variable names, input names, and paths to the data to make sure that you refer to the existing variables and inputs.

    Make sure that your string expression refers to the existing variables and inputs. The string expression can contain numbers, variables ($variable.variable-name), and input values ($input.input-name.path-to-datum).

  • Error: Failed to set the timer named <timer-name>. Check your duration expression, and try again.

    See the SetTimerAction action to ensure that you specified the correct parameters, and then set the timer again.

For more information, see Enable Amazon CloudWatch logging when developing AWS IoT Events detector models.

Amazon CloudWatch payload errors

You can set up Amazon CloudWatch Logs to monitor AWS IoT Events detector model instances. The following are common errors and warnings generated by AWS IoT Events, when you configure the action payload.

  • Error: We couldn't evaluate your expression for the action. Make sure that the variable names, input names, and paths to the data refer to the existing variables and input values. Also, verify that the size of the payload is less than 1 KB, the maximum allowed size of a payload.

    Make sure that you enter the correct variable names, input names, and paths to the data. You might also receive this error message if the action payload is larger than 1 KB.

  • Error: We couldn't parse your content expression for the payload of <action-type>. Enter a content expression with the correct syntax.

    The content expression can contain strings ('string'), variables ($variable.variable-name), input values ($input.input-name.path-to-datum), string concatenations, and strings that contain ${}.

  • Error: Your payload expression {expression} isn't valid. The defined payload type is JSON, so you must specify an expression that AWS IoT Events would evaluate to a string.

    If the specified payload type is JSON, AWS IoT Events first checks if the service can evaluate your expression to a string. The evaluated result can't be a Boolean or number. If the validation fails, you might receive this error.

  • Warning: The action was executed, but we couldn't evaluate your content expression for the action payload to valid JSON. The defined payload type is JSON.

    Make sure that AWS IoT Events can evaluate your content expression for the action payload to valid JSON, if you define the payload type as JSON. AWS IoT Events runs the action even if AWS IoT Events can't evaluate the content expression to valid JSON.

For more information, see Enable Amazon CloudWatch logging when developing AWS IoT Events detector models.

Incompatible data types

Message: Incompatible data types [<inferred-types>] found for <reference> in the following expression: <expression>

You might receive this error for one of the following reasons:

  • The evaluated results of your references are not compatible with other operands in your expressions.

  • The type of the argument passed to a function is not supported.

When you use references in expressions, check the following:

  • When you use a reference as an operand with one or more operators, make sure that all data types that you reference are compatible.

    For example, in the following expression, integer 2 is an operand of both the == and && operators. To ensure that the operands are compatible, $variable.testVariable + 1 and $variable.testVariable must reference an integer or decimal.

    In addition, integer 1 is an operand of the + operator. Therefore, $variable.testVariable must reference an integer or decimal.

    ‘$variable.testVariable + 1 == 2 && $variable.testVariable’

  • When you use a reference as an argument passed to a function, make sure that the function supports the data types that you reference.

    For example, the following timeout("time-name") function requires a string with double quotes as the argument. If you use a reference for the timer-name value, you must reference a string with double quotes.

    timeout("timer-name")
    Note

    For the convert(type, expression) function, if you use a reference for the type value, the evaluated result of your reference must be String, Decimal, or Boolean.

For more information, see AWS IoT Events reference for inputs and variables in expressions.

Failed to send message to AWS IoT Events

Message: Failed to send message to Iot Events

You might experience this error for the following reasons:

  • The input message payload does not contain the Input attribute Key.

  • The Input attribute Key is not in the same JSON path as specified in the input definition.

  • The input message does not match with the schema, as defined in the AWS IoT Events input.

Note

The data ingestion from other services will also experience failure.

For example in AWS IoT Core, the AWS IoT rule will fail with the following message Verify the Input Attribute key.

To resolve this, ensure that the input payload message schema conforms to the AWS IoT Events Input definition and the Input attribute Key location matches. For more information, see Create an input for models in AWS IoT Events to learn how to define AWS IoT Events Inputs.