Package software.amazon.awscdk.triggers

Triggers

See: Description

Interface Summary

Interface	Description
ITrigger	Interface for triggers.
ITrigger.Jsii$Default	Internal default implementation for ITrigger.
TriggerFunctionProps	Props for `InvokeFunction`.
TriggerOptions	Options for `Trigger`.
TriggerProps	Props for `Trigger`.

Class Summary

Class	Description
ITrigger.Jsii$Proxy	A proxy class which represents a concrete javascript instance of this type.
Trigger	Triggers an AWS Lambda function during deployment.
Trigger.Builder	A fluent builder for Trigger.
TriggerFunction	Invokes an AWS Lambda function during deployment.
TriggerFunction.Builder	A fluent builder for TriggerFunction.
TriggerFunctionProps.Builder	A builder for TriggerFunctionProps
TriggerFunctionProps.Jsii$Proxy	An implementation for TriggerFunctionProps
TriggerOptions.Builder	A builder for TriggerOptions
TriggerOptions.Jsii$Proxy	An implementation for TriggerOptions
TriggerProps.Builder	A builder for TriggerProps
TriggerProps.Jsii$Proxy	An implementation for TriggerProps

Enum Summary

Enum	Description
TriggerInvalidation	Determines.

Package software.amazon.awscdk.triggers Description

Triggers

Triggers allows you to execute code during deployments. This can be used for a variety of use cases such as:

• Self tests: validate something after a resource/construct been provisioned
• Data priming: add initial data to resources after they are created
• Preconditions: check things such as account limits or external dependencies before deployment.

Usage

The TriggerFunction construct will define an AWS Lambda function which is triggered during deployment:

 // Example automatically generated from non-compiling source. May contain errors.
 import software.amazon.awscdk.services.lambda.*;
 import software.amazon.awscdk.triggers.*;
 import software.amazon.awscdk.Stack;
 
 Stack stack;
 
 
 TriggerFunction.Builder.create(stack, "MyTrigger")
         .runtime(Runtime.NODEJS_14_X)
         .handler("index.handler")
         .code(Code.fromAsset(__dirname + "/my-trigger"))
         .build();
 

In the above example, the AWS Lambda function defined in myLambdaFunction will be invoked when the stack is deployed.

Trigger Failures

If the trigger handler fails (e.g. an exception is raised), the CloudFormation deployment will fail, as if a resource failed to provision. This makes it easy to implement "self tests" via triggers by simply making a set of assertions on some provisioned infrastructure.

Order of Execution

By default, a trigger will be executed by CloudFormation after the associated handler is provisioned. This means that if the handler takes an implicit dependency on other resources (e.g. via environment variables), those resources will be provisioned before the trigger is executed.

In most cases, implicit ordering should be sufficient, but you can also use executeAfter and executeBefore to control the order of execution.

The following example defines the following order: (hello, world) => myTrigger => goodbye. The resources under hello and world will be provisioned in parallel, and then the trigger myTrigger will be executed. Only then the resources under goodbye will be provisioned:

 // Example automatically generated from non-compiling source. May contain errors.
 import software.constructs.Construct;
 import software.constructs.Node;
 import software.amazon.awscdk.triggers.*;
 
 Trigger myTrigger;
 Construct hello;
 Construct world;
 Construct goodbye;
 
 
 myTrigger.executeAfter(hello, world);
 myTrigger.executeBefore(goodbye);
 

Note that hello and world are construct scopes. This means that they can be specific resources (such as an s3.Bucket object) or groups of resources composed together into constructs.

Re-execution of Triggers

By default, executeOnHandlerChange is enabled. This implies that the trigger is re-executed every time the handler function code or configuration changes. If this option is disabled, the trigger will be executed only once upon first deployment.

In the future we will consider adding support for additional re-execution modes:

• executeOnEveryDeployment: boolean - re-executes every time the stack is deployed (add random "salt" during synthesis).
• executeOnResourceChange: Construct[] - re-executes when one of the resources under the specified scopes has changed (add the hash the CloudFormation resource specs).