policy.go

package g8

import (
	"strings"
)

const All = "*"

type Effect int

const (
	Allow Effect = iota
	Deny
)

func (e Effect) String() string {
	switch e {
	case Allow:
		return "Allow"
	case Deny:
		return "Deny"
	}
	return ""
}

type methodARN struct {

	// The region where the API is deployed. By default this is set to '*'
	Region string

	// The AWS account id the policy will be generated for. This is used to create the method ARNs.
	AccountID string

	// The API Gateway API id. By default this is set to '*'
	APIID string

	// The name of the stage used in the policy. By default this is set to '*'
	Stage string
}

func parseFromMethodARN(rawArn string) methodARN {

	tmp := strings.Split(rawArn, ":")
	apiGatewayArnTmp := strings.Split(tmp[5], "/")
	awsAccountID := tmp[4]

	return methodARN{
		AccountID: awsAccountID,
		Region:    tmp[3],
		APIID:     apiGatewayArnTmp[0],
		Stage:     apiGatewayArnTmp[1],
	}
}

func (r *methodARN) buildResourceARN(verb, resource string) string {
	var str strings.Builder

	str.WriteString("arn:aws:execute-api:")
	str.WriteString(r.Region)
	str.WriteString(":")
	str.WriteString(r.AccountID)
	str.WriteString(":")
	str.WriteString(r.APIID)
	str.WriteString("/")
	str.WriteString(r.Stage)
	str.WriteString("/")
	str.WriteString(verb)
	str.WriteString("/")
	str.WriteString(strings.TrimLeft(resource, "/"))

	return str.String()
}