README
¶
Overview
CloudFormation has a different way of responding to most events due to the way stacks execute.
It is best to catch all errors and ensure the correct response is sent to the pre-signed URL that comes with the event.
To make this easier, a wrapper exists to allow the creation of custom resources without having to handle that.
Sample Function
This sample will safely 'Echo' back anything given into the Echo parameter within the Custom Resource call.
import (
"context"
"fmt"
"github.com/aws/aws-lambda-go/cfn"
"github.com/aws/aws-lambda-go/lambda"
)
func echoResource(ctx context.Context, event cfn.Event) (physicalResourceID string, data map[string]interface{}, err error) {
v, _ := event.ResourceProperties["Echo"].(string)
data = map[string]interface{} {
"Echo": v,
}
return
}
func main() {
lambda.Start(cfn.LambdaWrap(echoResource))
}
Documentation
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Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type CustomResourceFunction ¶
type CustomResourceFunction func(context.Context, Event) (physicalResourceID string, data map[string]interface{}, err error)
CustomResourceFunction is a representation of the customer's Custom Resource function. LambdaWrap will take the returned values and turn them into a response to be sent to CloudFormation.
type CustomResourceLambdaFunction ¶
CustomResourceLambdaFunction is a standard form Lambda for a Custom Resource.
func LambdaWrap ¶
func LambdaWrap(lambdaFunction CustomResourceFunction) (fn CustomResourceLambdaFunction)
LambdaWrap returns a CustomResourceLambdaFunction which is something lambda.Start() will understand. The purpose of doing this is so that Response Handling boiler plate is taken away from the customer and it makes writing a Custom Resource simpler.
func myLambda(ctx context.Context, event cfn.Event) (physicalResourceID string, data map[string]interface{}, err error) {
physicalResourceID = "arn:...."
return
}
func main() {
lambda.Start(cfn.LambdaWrap(myLambda))
}
type Event ¶
type Event struct {
RequestType RequestType `json:"RequestType"`
RequestID string `json:"RequestId"`
ResponseURL string `json:"ResponseURL"`
ResourceType string `json:"ResourceType"`
PhysicalResourceID string `json:"PhysicalResourceId,omitempty"`
LogicalResourceID string `json:"LogicalResourceId"`
StackID string `json:"StackId"`
ResourceProperties map[string]interface{} `json:"ResourceProperties"`
OldResourceProperties map[string]interface{} `json:"OldResourceProperties,omitempty"`
}
Event is a representation of a Custom Resource request
type RequestType ¶
type RequestType string
RequestType represents the types of requests that come from a CloudFormation stack being run
const ( RequestCreate RequestType = "Create" RequestUpdate RequestType = "Update" RequestDelete RequestType = "Delete" )
type Response ¶
type Response struct {
Status StatusType `json:"Status"`
RequestID string `json:"RequestId"`
LogicalResourceID string `json:"LogicalResourceId"`
StackID string `json:"StackId"`
PhysicalResourceID string `json:"PhysicalResourceId"`
Reason string `json:"Reason,omitempty"`
NoEcho bool `json:"NoEcho,omitempty"`
Data map[string]interface{} `json:"Data,omitempty"`
// contains filtered or unexported fields
}
Response is a representation of a Custom Resource response expected by CloudFormation.
func NewResponse ¶
NewResponse creates a Response with the relevant verbatim copied data from a Event
type StatusType ¶
type StatusType string
StatusType represents a CloudFormation response status
const ( StatusSuccess StatusType = "SUCCESS" StatusFailed StatusType = "FAILED" )
Source Files