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v2.274.0

RuleTargetInput Class ​

The input to send to the event target.

This class abstracts over the three different ways CloudFormation lets you shape a target's input, so you do not have to choose between them yourself:

  • Input - a literal value, emitted when the input does not reference the event.
  • InputPath - a single JSONPath into the event, emitted by fromEventPath().
  • InputTransformer - an InputPathsMap plus an InputTemplate, emitted automatically when the input references parts of the event via EventField.

You pick a factory method based on the shape you want the target to receive, and whether you reference EventField determines which of the above is synthesized. For example, fromObject({ foo: 'bar' }) produces a literal Input, while fromObject({ id: EventField.fromPath('$.detail.instance-id') }) produces an InputTransformer with the path lifted into InputPathsMap.

Source
aws-events/lib/input.ts
Type last changed
v2.235.0 · 15 Jan 2026

Example ​

ts
declare const rule: events.Rule;
declare const topic: sns.Topic;

// Without EventField this is a literal `Input`:
//   {"source":"my-app"}
rule.addTarget(new targets.SnsTopic(topic, {
  message: events.RuleTargetInput.fromObject({ source: 'my-app' }),
}));

// Referencing the event inserts those fields from each matched event.
rule.addTarget(new targets.SnsTopic(topic, {
  message: events.RuleTargetInput.fromObject({
    instance: events.EventField.fromPath('$.detail.instance-id'),
    state: events.EventField.fromPath('$.detail.state'),
  }),
}));

Initializer ​

ts
new RuleTargetInput()
python
RuleTargetInput()
java
new RuleTargetInput()
csharp
new RuleTargetInput()
go
NewRuleTargetInput()

Methods ​

bind(rule: IRuleRef): RuleTargetInputPropertiesdef bind(self, rule: IRuleRef) -> RuleTargetInputPropertiespublic RuleTargetInputProperties bind(IRuleRef rule)public RuleTargetInputProperties Bind(IRuleRef rule)func Bind(Rule IRuleRef) RuleTargetInputProperties#
Return the input properties for this input object.
fromEventPath(path: string): RuleTargetInput // chainable@staticmethod def from_event_path(path: str) -> RuleTargetInputpublic static RuleTargetInput fromEventPath(String path)public static RuleTargetInput FromEventPath(string path)func FromEventPath(Path *string) RuleTargetInputstatic#
Take the event target input from a path in the event JSON.

This emits CloudFormation's InputPath directly, so the target receives only the selected fragment of the event. Use this when you want to forward part of the event unchanged; use fromObject() when you need to reshape it.

fromMultilineText(text: string): RuleTargetInput // chainable@staticmethod def from_multiline_text(text: str) -> RuleTargetInputpublic static RuleTargetInput fromMultilineText(String text)public static RuleTargetInput FromMultilineText(string text)func FromMultilineText(Text *string) RuleTargetInputstatic#
Pass text to the event target, splitting on newlines.
notes

This is only useful when passing to a target that does not take a single argument.

May contain strings returned by EventField.from() to substitute in parts of the matched event.

As with fromText, each line is JSON-encoded, so every line is wrapped in double quotes in the synthesized template. Whether those quotes are visible to the recipient depends on the target service.

fromObject(obj: any): RuleTargetInput // chainable@staticmethod def from_object(obj: Any) -> RuleTargetInputpublic static RuleTargetInput fromObject(Object obj)public static RuleTargetInput FromObject(object obj)func FromObject(Obj interface{}) RuleTargetInputstatic#
Pass a JSON object to the event target.

May contain strings returned by EventField.from() to substitute in parts of the matched event.

returns · example

Returns: RuleTargetInput

ts
declare const rule: events.Rule;
declare const topic: sns.Topic;

// Without EventField this is a literal `Input`:
//   {"source":"my-app"}
rule.addTarget(new targets.SnsTopic(topic, {
  message: events.RuleTargetInput.fromObject({ source: 'my-app' }),
}));

// Referencing the event inserts those fields from each matched event.
rule.addTarget(new targets.SnsTopic(topic, {
  message: events.RuleTargetInput.fromObject({
    instance: events.EventField.fromPath('$.detail.instance-id'),
    state: events.EventField.fromPath('$.detail.state'),
  }),
}));
fromText(text: string): RuleTargetInput // chainable@staticmethod def from_text(text: str) -> RuleTargetInputpublic static RuleTargetInput fromText(String text)public static RuleTargetInput FromText(string text)func FromText(Text *string) RuleTargetInputstatic#
Pass text to the event target.
notes

May contain strings returned by EventField.from() to substitute in parts of the matched event.

The Rule Target input value will be a single string: the string you pass here. Do not use this method to pass a complex value like a JSON object to a Rule Target. Use RuleTargetInput.fromObject() instead.

The target Input field must be valid JSON, so the text is JSON-encoded when the template is synthesized. As a result a plain string is wrapped in double quotes: fromText('something') renders as Input: '"something"'. The quotes are part of the required JSON encoding, not an extra value added by CDK, and cannot be removed.

Whether those quotes are visible to the recipient depends on the target service. Some targets deliver the JSON-encoded value as-is, so the recipient sees the surrounding quotes (for example, an SNS topic delivering to an email subscriber shows "something"). To send a structured payload, use RuleTargetInput.fromObject() instead.