如何在Cloudformation中将参数从主模板发送到子模板

Question

I am trying to get two parameter from a user and then pass it to the template that I address in my main template. in my main template I have:

{
"Parameters": {
    "appName": {
        "Description": "enter the app name",
        "Type": "String",
        "Default": "bn-test-jun"
    },
    "appEnv": {
        "Description": "enter the app name",
        "Type": "String",
        "Default": "bn-test-jun"
    }
},
"Resources": {
    "CodeDeployEC2InstancesStack": {
        "Type": "AWS::CloudFormation::Stack",
        "Properties": {
            "TemplateURL": "https://s3.amazonaws.com/............../beanstalk.json",
            "TimeoutInMinutes": "60"
        }
    },
    "myS3": {
        "Type": "AWS::S3::Bucket",
        "Properties": {
            "AccessControl": "PublicRead",
            "BucketName": "ssssssss-test"
        }
    }
}
}

As you can see I am addressing the beanstalk template and I get the name of the environment and application of the beanstalk I am going to create so I need to pass these variable to the beanstalk template. Here is my beanstalk template:

{
"AWSTemplateFormatVersion": "2010-09-09",
"Parameters": {
    "appName": {
        "Description": "enter the app name",
        "Type": "String",
        "Default": "bn-test-jun"
    },
    "appEnv": {
        "Description": "enter the app name",
        "Type": "String",
        "Default": "bn-test-jun"
    }
},
"Resources": {
    "sampleApplication": {
        "Type": "AWS::ElasticBeanstalk::Application",
        "Properties": {
            "Description": "AWS Elastic Beanstalk Sample Application",
            "ApplicationName": {
                "Ref": "appName"
            }
        }
    },
    "sampleApplicationVersion": {
        "Type": "AWS::ElasticBeanstalk::ApplicationVersion",
        "Properties": {
            "ApplicationName": {
                "Ref": "sampleApplication"
            },
            "Description": "AWS ElasticBeanstalk Sample Application Version",
            "SourceBundle": {
                "S3Bucket": "hamed-test-war",
                "S3Key": "deployment.war"
            }
        }
    },
    "sampleConfigurationTemplate": {
        "Type": "AWS::ElasticBeanstalk::ConfigurationTemplate",
        "Properties": {
            "ApplicationName": {
                "Ref": "sampleApplication"
            },
            "Description": "AWS ElasticBeanstalk Sample Configuration Template",
            "OptionSettings": [{
                    "Namespace": "aws:autoscaling:asg",
                    "OptionName": "MinSize",
                    "Value": "2"
                },
                {
                    "Namespace": "aws:autoscaling:asg",
                    "OptionName": "MaxSize",
                    "Value": "3"
                },
                {
                    "Namespace": "aws:elasticbeanstalk:environment",
                    "OptionName": "EnvironmentType",
                    "Value": "LoadBalanced"
                }
            ],
            "SolutionStackName": "64bit Amazon Linux 2017.03 v2.6.1 running Tomcat 8 Java 8"
        }
    },
    "sampleEnvironment": {
        "Type": "AWS::ElasticBeanstalk::Environment",
        "Properties": {
            "ApplicationName": {
                "Ref": "sampleApplication"
            },
            "Description": "AWS ElasticBeanstalk Sample Environment",
            "TemplateName": {
                "Ref": "sampleConfigurationTemplate"
            },
            "VersionLabel": {
                "Ref": "sampleApplicationVersion"
            },
            "EnvironmentName": {
                "Ref": "appEnv"
            }
        }
    }
},
"Outputs": {
    "applicationName11": {
        "Description": "The application chosen by user is :",
        "Value": {
            "Ref": "appEnv"
        }
    }
}

}

As you see I am trying to use Ref appname to get the variable but this does not work because the appname in available only in the parent template. So I am looking for a way to send the param to the beanstalk.template. Is it possible to do that?

Answer 1

It seems you are using nested stacks to pull in the template. If so a Parameters property can be used to pass your parameters in to the child template as shown here:

{
   "AWSTemplateFormatVersion" : "2010-09-09",
   "Resources" : {
      "myStackWithParams" : {
         "Type" : "AWS::CloudFormation::Stack",
         "Properties" : {
            "TemplateURL" : "https://s3.amazonaws.com/cloudformation-templates-us-east-1/EC2ChooseAMI.template",
            "Parameters" : {
               "InstanceType" : "t1.micro",
               "KeyName" : "mykey"
            }
         }
      }
   }
}