AWS iotevents documentation change
Summary
Added end-of-support notice for AWS IoT Events and comprehensive documentation for built-in functions, input/variable references, and substitution templates in expressions
Security assessment
The changes include a service deprecation notice and documentation updates for expression functions. There's no evidence of addressing security vulnerabilities or introducing security-specific features. The added functions enhance general functionality but are not explicitly security-related.
Diff
diff --git a/iotevents/latest/developerguide/iotevents-expressions.md b/iotevents/latest/developerguide/iotevents-expressions.md index 348358ab8..fdb71cf88 100644 --- a//iotevents/latest/developerguide/iotevents-expressions.md +++ b//iotevents/latest/developerguide/iotevents-expressions.md @@ -6,0 +7,2 @@ Syntax to filter device data +End of support notice: On May 20, 2026, AWS end support for AWS IoT Events. After May 20, 2026, you will no longer be able to access the AWS IoT Events console or AWS IoT Events resources. For more information, visit this [AWS IoT Events end of support](https://docs.aws.amazon.com/iotevents/latest/developerguide/iotevents-end-of-support.html). + @@ -133,0 +136,291 @@ You can use parentheses to group terms within an expression. +### Functions to use in AWS IoT Events expressions + +AWS IoT Events provides a set of built-in functions to enhance the capabilities of your detector model expressions. These functions enable timer management, type conversion, null checking, trigger type identification, input verification, string manipulation, and bitwise operations. By leveraging these functions, you can create a responsive AWS IoT Events processing logic, improving the overall effectiveness of your IoT applications. + +Built-in Functions + + +`**timeout**("`timer-name`")` + + +Evaluates to `true` if the specified timer has elapsed. Replace "`_timer-name_`" with the name of a timer that you defined, in quotation marks. In an event action, you can define a timer and then start the timer, reset it, or clear one that you previously defined. See the field `detectorModelDefinition.states.onInput|onEnter|onExit.events.actions.setTimer.timerName`. + +A timer set in one state can be referenced in a different state. You must visit the state in which you created the timer before you enter the state in which the timer is referenced. + +For example, a detector model has two states, `TemperatureChecked` and `RecordUpdated`. You created a timer in the `TemperatureChecked` state. You must visit the `TemperatureChecked` state first before you can use the timer in the `RecordUpdated` state. + +To ensure accuracy, the minimum time that a timer should be set is 60 seconds. + +###### Note + +`timeout()` returns `true` only the first time it's checked following the actual timer expiration and returns `false` thereafter. + +`**convert**(`type`, `expression`)` + + +Evaluates to the value of the expression converted to the specified type. The `type` value must be `String`, `Boolean`, or `Decimal`. Use one of these keywords or an expression that evaluates to a string containing the keyword. Only the following conversions succeed and return a valid value: + + * Boolean -> string + +Returns the string `"true"` or `"false"`. + + * Decimal -> string + + * String -> Boolean + + * String -> decimal + +The string specified must be a valid representation of a decimal number, or `convert()` fails. + + + + +If `convert()` doesn't return a valid value, the expression that it's a part of is also invalid. This result is equivalent to `false` and won't trigger the `actions` or transition to the `nextState` specified as part of the event in which the expression occurs. + +`**isNull**(`expression`)` + + +Evaluates to `true` if the expression returns null. For example, if the input `MyInput` receives the message `{ "a": null }`, then the following evaluates to `true`, but `isUndefined($input.MyInput.a)` evaluates to `false`. + + + isNull($input.MyInput.a) + +`**isUndefined**(`expression`)` + + +Evaluates to `true` if the expression is undefined. For example, if the input `MyInput` receives the message `{ "a": null }`, then the following evaluates to `false`, but `isNull($input.MyInput.a)` evaluates to `true`. + + + isUndefined($input.MyInput.a) + +`**triggerType**("`type`")` + + +The `type` value can be `"Message"` or `"Timer"`. Evaluates to `true` if the event condition in which it appears is being evaluated because a timer has expired like in the following example. + + + triggerType("Timer") + +Or an input message was received. + + + triggerType("Message") + +`**currentInput**("`input`")` + + +Evaluates to `true` if the event condition in which it appears is being evaluated because the specified input message was received. For example, if the input `Command` receives the message `{ "value": "Abort" }`, then the following evaluates to `true`. + + + currentInput("Command") + +Use this function to verify that the condition is being evaluated because a particular input has been received and a timer hasn't expired, as in the following expression. + + + currentInput("Command") && $input.Command.value == "Abort" + +String Matching Functions + + +`**startsWith**(`expression1`, `expression2`)` + + +Evaluates to `true` if the first string expression starts with the second string expression. For example, if input `MyInput` receives the message `{ "status": "offline"}`, then the following evaluates to `true`. + + + startsWith($input.MyInput.status, "off") + +Both expressions must evaluate to a string value. If either expression does not evaluate to a string value, then the result of the function is undefined. No conversions are performed. + +`**endsWith**(`expression1`, `expression2`)` + + +Evaluates to `true` if the first string expression ends with the second string expression. For example, if input `MyInput` receives the message `{ "status": "offline" }`, then the following evaluates to `true`. + + + endsWith($input.MyInput.status, "line") + +Both expressions must evaluate to a string value. If either expression does not evaluate to a string value, then the result of the function is undefined. No conversions are performed. + +`**contains**(`expression1`, `expression2`)` + + +Evaluates to `true` if the first string expression contains the second string expression. For example, if input `MyInput` receives the message `{ "status": "offline" }`, then the following evaluates to `true`. + + + contains($input.MyInput.value, "fli") + +Both expressions must evaluate to a string value. If either expression does not evaluate to a string value, then the result of the function is undefined. No conversions are performed. + +Bitwise Integer Manipulation Functions + + +`**bitor**(`expression1`, `expression2`)` + + +Evaluates the bitwise OR of the integer expressions (the binary OR operation is performed on the corresponding bits of the integers). For example, if input `MyInput` receives the message `{ "value1": 13, "value2": 5 }`, then the following evaluates to `13`. + + + bitor($input.MyInput.value1, $input.MyInput.value2) + +Both expressions must evaluate to an integer value. If either expression does not evaluate to an integer value, then the result of the function is undefined. No conversions are performed. + +`**bitand**(`expression1`, `expression2`)` + + +Evaluates the bitwise AND of the integer expressions (the binary AND operation is performed on the corresponding bits of the integers). For example, if input `MyInput` receives the message `{ "value1": 13, "value2": 5 }`, then the following evaluates to `5`. + + + bitand($input.MyInput.value1, $input.MyInput.value2) + +Both expressions must evaluate to an integer value. If either expression does not evaluate to an integer value, then the result of the function is undefined. No conversions are performed. + +`**bitxor**(`expression1`, `expression2`)` + + +Evaluates the bitwise XOR of the integer expressions (the binary XOR operation is performed on the corresponding bits of the integers). For example, if input `MyInput` receives the message `{ "value1": 13, "value2": 5 }`, then the following evaluates to `8`. + + + bitxor($input.MyInput.value1, $input.MyInput.value2) + +Both expressions must evaluate to an integer value. If either expression does not evaluate to an integer value, then the result of the function is undefined. No conversions are performed. + +`**bitnot**(`expression`)` + + +Evaluates the bitwise NOT of the integer expression (the binary NOT operation is performed on the bits of the integer). For example, if input `MyInput` receives the message `{ "value": 13 }`, then the following evaluates to `-14`. + + + bitnot($input.MyInput.value) + +Both expressions must evaluate to an integer value. If either expression does not evaluate to an integer value, then the result of the function is undefined. No conversions are performed. + +### AWS IoT Events reference for inputs and variables in expressions + +Inputs + + +`$input.`input-name`.`path-to-data`` + +`input-name` is an input that you create using the [CreateInput](https://docs.aws.amazon.com/iotevents/latest/apireference/API_CreateInput.html) action. + +For example, if you have an input named `TemperatureInput` for which you defined `inputDefinition.attributes.jsonPath` entries, the values might appear in the following available fields. + + + { + "temperature": 78.5, + "date": "2018-10-03T16:09:09Z" + } + +To reference the value of the `temperature` field, use the following command. + + + $input.TemperatureInput.temperature + +For fields whose values are arrays, you can reference members of the array using `[`n`]`. For example, given the following values: + + + { + "temperatures": [ + 78.4, + 77.9, + 78.8