AWS::Events::Rule InputTransformer - AWS CloudFormation
SyntaxPropertiesExamples

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AWS::Events::Rule InputTransformer

Contains the parameters needed for you to provide custom input to a target based on one or more pieces of data extracted from the event.

Syntax

To declare this entity in your AWS CloudFormation template, use the following syntax:

JSON

{
  "InputPathsMap" : {Key: Value, ...},
  "InputTemplate" : String
}

YAML

  InputPathsMap: 
    Key: Value
  InputTemplate: String

Properties

InputPathsMap

Map of JSON paths to be extracted from the event. You can then insert these in the template in InputTemplate to produce the output you want to be sent to the target.

InputPathsMap is an array key-value pairs, where each value is a valid JSON path. You can have as many as 100 key-value pairs. You must use JSON dot notation, not bracket notation.

The keys cannot start with "AWS."

Required: No

Type: Object of String

Pattern: [a-zA-Z0-9]+

Update requires: No interruption

InputTemplate

Input template where you specify placeholders that will be filled with the values of the keys from InputPathsMap to customize the data sent to the target. Enclose each InputPathsMaps value in brackets: <value>

If InputTemplate is a JSON object (surrounded by curly braces), the following restrictions apply:

  • The placeholder cannot be used as an object key.

The following example shows the syntax for using InputPathsMap and InputTemplate.

"InputTransformer":

{

"InputPathsMap": {"instance": "$.detail.instance","status": "$.detail.status"},

"InputTemplate": "<instance> is in state <status>"

}

To have the InputTemplate include quote marks within a JSON string, escape each quote marks with a slash, as in the following example:

"InputTransformer":

{

"InputPathsMap": {"instance": "$.detail.instance","status": "$.detail.status"},

"InputTemplate": "<instance> is in state \"<status>\""

}

The InputTemplate can also be valid JSON with varibles in quotes or out, as in the following example:

"InputTransformer":

{

"InputPathsMap": {"instance": "$.detail.instance","status": "$.detail.status"},

"InputTemplate": '{"myInstance": <instance>,"myStatus": "<instance> is in state \"<status>\""}'

}

Required: Yes

Type: String

Minimum: 1

Maximum: 8192

Update requires: No interruption

Examples

Transform input into a string

The following example takes instance and state and outputs a string.

JSON

"InputTransformer": {
    "InputPathsMap": {
       "instance": "$.detail.instance-id",
       "state": "$.detail.state"
    },
    "InputTemplate": "\"instance <instance> is in <state>\"\n  }\n"
}

YAML

InputTransformer:
  InputPathsMap:
    "instance" : "$.detail.instance-id"
    "state" : "$.detail.state"
  InputTemplate: |
    "instance <instance> is in <state>"

Transform input into JSON

The following example takes instance and state and outputs JSON that includes strings and variables.

JSON

"InputTransformer": {
    "InputPathsMap": {
       "instance": "$.detail.instance-id",
       "state": "$.detail.state"
    },
    "InputTemplate": "{\n   \"instance\" : <instance>,\n   \"state\" : <state>,\n   \"instanceStatus\": \"instance \\\"<instance>\\\" is in <state>\"\n}\n"
}

YAML

InputTransformer:
  InputPathsMap:
    "instance" : "$.detail.instance-id"
    "state" : "$.detail.state"
  InputTemplate: |
    {
       "instance" : <instance>,
       "state" : <state>,
       "instanceStatus": "instance \"<instance>\" is in <state>"
    }

Transform input and substitute a variable

The following example defines a variable RootDomainName. It then takes instance and state, substitutes RootDomainName for domain, and outputs JSON.

JSON

"Parameters": {
    "RootDomainName": {
        "Description": "Domain name to use",
        "Type": "String",
        "Default": "testdomain.com"
    }
},

JSON

"InputTransformer": {
    "InputPathsMap": {
       "instance": "$.detail.instance-id",
       "state": "$.detail.state"
    },
    "InputTemplate": {
        "Fn::Sub": [
            "{\n   \"domain\": \"${Domain}\",\n   \"instance\" : <instance>,\n   \"state\" : <state>,\n   \"instanceStatus\": \"instance \\\"<instance>\\\" is in <state>\"\n} - ( Domain: !Ref RootDomainName )\n"
        ]
    }
}

YAML

Parameters:
  RootDomainName:
    Description: Domain name to use
    Type: String
    Default: testdomain.com

YAML

InputTransformer:
  InputPathsMap:
    "instance" : "$.detail.instance-id"
    "state" : "$.detail.state"
  InputTemplate: !Sub 
    - |
      {
         "domain": "${Domain}",
         "instance" : <instance>,
         "state" : <state>,
         "instanceStatus": "instance \"<instance>\" is in <state>"
      }
    - Domain: !Ref RootDomainName