aws-cfn-update

Programmatically update CloudFormation templates. It will update both .yaml and .json formats of a CloudFormation template. Note that formatting and comments may be lost.

Commands:

  container-image           Updates the Docker image of ECS Container Task definition
  latest-ami                Updates the AMI name of Custom::AMI resources
  cron-schedule-expression  Updates the schedule expression of an AWS::Events::Rules resources
  remove-resource           Removes the specified CloudFormation resource
  add-new-resources         add new resources that exist in the new template
  lambda-inline-code        Updates the inline code of an Lambda
  rest-api-body             Updates the body of a REST API Resource
  state-machine-definition  Updates the definition of an AWS::StepFunctions::StateMachine.

remove-resource - removes the specified resource and all referencing resources

will remove the specified resource and all of the references. For example, the command:

aws-cfn-update remove-resource --resource AMI .

will update:

Resources:
  AMI: 
    Type: Custom::AMI
  EC2Instance:
    ImageId: !Ref AMI
  AMIv2:
    Type: Custom::AMI

to:

Resources:
  AMIv2:
    Type: Custom::AMI

add-new-resources - adds new resources from another template

will add missing parameters, conditions, mappings and resources from another template to this template. For example, given the following template:

Parameters:
  Vpc:
    Type: String
Resources:
  AMI: 
    Type: Custom::AMI
  AMIv2: 
    Type: Custom::AMI
  EC2Instance:
    ImageId: !Ref AMI

The following command:

aws-cfn-update add-new-resources --source new.yaml old.yaml

will update old.yaml:

Resources:
  AMI: 
    Type: Custom::AMI
  EC2Instance:
    ImageId: !Ref AMI

to:

Parameters:
  Vpc:
    Type: String
Resources:
  AMI: 
    Type: Custom::AMI
  AMIv2: 
    Type: Custom::AMI
  EC2Instance:
    ImageId: !Ref AMI

container-image - Updates the Docker image of ECS Container Definitions.

will update any container definition where the base image name matches the specified image name excluding the tag. For example, the command:

aws-cfn-update container-image --image mvanholsteijn/paas-monitor:0.6.0

will update:

  Type: AWS::ECS::TaskDefinition
  Properties:
    ContainerDefinitions:
      - Name: paas-monitor
        Image: mvanholsteijn/paas-monitor:0.5.9

to::

  Type: AWS::ECS::TaskDefinition
  Properties:
    ContainerDefinitions:
      - Name: paas-monitor
        Image: mvanholsteijn/paas-monitor:0.6.0

latest-ami - Updates the AMI name of Custom::AMI resources

will update the AMI name of Custom::AMI resources to the latest version.

For example, the command:

aws-cfn-update latest-ami --ami-name-pattern 'amzn-ami-*ecs-optimized'

Updates the AMI name of Custom::AMI resources to the latest version. It will update the following resource definition from:

         Type: Custom::AMI
         Properties:
           Filters:
             name: amzn-ami-2017.09.a-amazon-ecs-optimized
           Owners:
             - amazon

to:

         Type: Custom::AMI
         Properties:
           Filters:
             name: amzn-ami-2017.09.l-amazon-ecs-optimized
           Owners:
             - amazon

By specifying --add-new-version, a new Custom::AMI will be added to the template with a new name. A suffix v<version> is appended to create the new resource. The highest reference to the Custom::AMI resource is replaced. It will change:

      CustomAMI:
         Type: Custom::AMI
         Properties:
           Filters:
             name: amzn-ami-2017.09.a-amazon-ecs-optimized
           Owners:
             - amazon
      CustomAMIv2:
         Type: Custom::AMI
         Properties:
           Filters:
             name: amzn-ami-2017.09.b-amazon-ecs-optimized
           Owners:
             - amazon
      Instance:
         Type: AWS::EC2::Instance
         Properties:
            ImageId: !Ref CustomAMIv2
Outputs:
  OldestAMI:
    Value: !Ref CustomAMI

to:

      CustomAMI:
         Type: Custom::AMI
         Properties:
           Filters:
             name: amzn-ami-2017.09.a-amazon-ecs-optimized
           Owners:
             - amazon
      CustomAMIv2:
         Type: Custom::AMI
         Properties:
           Filters:
             name: amzn-ami-2017.09.b-amazon-ecs-optimized
           Owners:
             - amazon
      CustomAMIv3:
         Type: Custom::AMI
         Properties:
           Filters:
             name: amzn-ami-2017.09.l-amazon-ecs-optimized
           Owners:
             - amazon
      Instance:
         Type: AWS::EC2::Instance
         Properties:
            ImageId: !Ref CustomAMIv3		# <--- updated this
Outputs:
  OldestAMI:
    Value: !Ref CustomAMI			# <-- unchanged

container-image - Updates the Docker image of ECS Container Definitions.

Updates the schedule expression of an AWS::Events::Rules resources to reflect the scheduled time in UTC. The required cron rule is taken from the description. It will update the following resource definition from:

DailyTaskSchedule:
  Type: AWS::Events::Rule
  Properties:
    Description: run daily - cron(30 01 * * ? *)
    Name: run daily
    ScheduleExpression: cron(30 01 * * ? *)
    State: ENABLED

to:

DailyTaskSchedule:
  Type: AWS::Events::Rule
  Properties:
    Description: run daily - cron(30 01 * * ? *)
    Name: run daily
    ScheduleExpression: cron(30 23 * * ? *)
    State: ENABLED

with --timezone Europe/Amsterdam and --date 2018-08-01. If the updater is run with --date 2018-12-01, it will change it to:

DailyTaskSchedule:
  Type: AWS::Events::Rule
  Properties:
    Description: run daily - cron(30 01 * * ? *)
    Name: run daily
    ScheduleExpression: cron(30 00 * * ? *)
    State: ENABLED

rest-api-body - update the body of an AWS::ApiGateway::RestApi

Updates the body of a REST API Resource, with an standard Open API specification merged with AWS API Gateway extensions.

If you specify --add-new-version, it will create a new version of the resource and update all references to it. This will enforce the deployment of the new api.

If you want to keep the previous definition, specify --keep to a value of 2 or higher. This might be handy if you have old clients still accessing the old version of the API.

If no changes are detected, no changes are made. Please make sure that all dictionary keys in th specifications are strings, not integers (especially the case with responses). When updating json CFN templates, the compare algorithm does not work properly.

Options:
  --resource TEXT                AWS::ApiGateway::RestApi body to update [required]
  --open-api-specification PATH  defining the interface  [required]
  --api-gateway-extensions PATH  to add the the specification  [required]
  --add-new-version              of the RestAPI resource and replace all references
  --keep INTEGER                 number of versions to keep, if --add-new-version is specified

lambda-inline-code - updates the inline code of an AWS::Lambda::Function resource.

Update the inline code of a AWS::Lambda::Function to include the content of the specified file. It changes:

    ELBListenerRuleProvider:
      Type: AWS::Lambda::Function
      Function: cfn-listener-rule-provider

into:

    ELBListenerRuleProvider:
      Type: AWS::Lambda::Function
      Properties:
        Code:
          ZipFile:
            import boto3
            import cfnresponse
            ELB = boto3.client('elbv2')
            ...
        Function: cfn-listener-rule-provider

state-machine-definition - updates the definition string of an AWS::StepFunctions::StateMachine

Updates the definition of an AWS::StepFunctions::StateMachine.

The definition is read from the file specified by --definition. By default, the content will be passed into the Fn::Sub function to allow references to parameters and resource attributes in the template.

If you do not want substitution for your definition, specify --no-fn-sub.

Options:
  --resource TEXT         AWS::StepFunctions::StateMachine definition to
                          update  [required]
  --definition PATH       of the state machine  [required]
  --fn-sub / --no-fn-sub  for the definition
  --help                  Show this message and exit.

For an example, check out ./samples/state-machine-definition

Installation

Simply run:

pip install aws-cfn-update

Usage

To use it:

aws-cfn-update --help