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terraform-aws-modules/terraform-aws-step-functions

AWS Step Functions Terraform module

Terraform module, which creates AWS Step Functions as well as required IAM role and IAM policies for Integrated Services.

This Terraform module is the part of serverless.tf framework, which aims to simplify all operations when working with the serverless in Terraform.

Features

Usage

Step Function

module "step_function" {
  source = "terraform-aws-modules/step-functions/aws"

  name       = "my-step-function"
  definition = <<EOF
{
  "Comment": "A Hello World example of the Amazon States Language using Pass states",
  "StartAt": "Hello",
  "States": {
    "Hello": {
      "Type": "Pass",
      "Result": "Hello",
      "Next": "World"
    },
    "World": {
      "Type": "Pass",
      "Result": "World",
      "End": true
    }
  }
}
EOF

  service_integrations = {
    dynamodb = {
      dynamodb = ["arn:aws:dynamodb:eu-west-1:052212379155:table/Test"]
    }

    lambda = {
      lambda = ["arn:aws:lambda:eu-west-1:123456789012:function:test1", "arn:aws:lambda:eu-west-1:123456789012:function:test2"]
    }

    stepfunction_Sync = {
      stepfunction = ["arn:aws:states:eu-west-1:123456789012:stateMachine:test1"]
      stepfunction_Wildcard = ["arn:aws:states:eu-west-1:123456789012:stateMachine:test1"]

      # Set to true to use the default events (otherwise, set this to a list of ARNs; see the docs linked in locals.tf
      # for more information). Without events permissions, you will get an error similar to this:
      #   Error: AccessDeniedException: 'arn:aws:iam::xxxx:role/step-functions-role' is not authorized to
      #   create managed-rule
      events = true
    }
  }

  type = "STANDARD"

  tags = {
    Module = "my"
  }
}

Service integration policies

There are predefined policies for all available integrations (see aws_service_policies in locals.tf for values) which can be used as a key inside service_integrations argument.

Each key of aws_service_policies contains configuration for the IAM policy statements which will be combined with the values specified in service_integrations argument.

Example of service_integrations arguments:

module "step_function" {
  source = "terraform-aws-modules/step-functions/aws"

  # ... omitted
  service_integrations = {
    xray = {
      xray = true  # the value of default_resources key will be used when key value is `true`
    }

    sqs = {
      sqs = ["arn:aws:sqs:..."]  # sqs queue ARN is required because there is no default_resources key for such integration
    }

    # Special case to deny all actions for the step function (this will override all IAM policies allowed for the function)
    no_tasks = {
      deny_all = true
    }
  }
}

Additional IAM policies for Step Function

In addition to all supported AWS service integrations you may want to create and attach additional policies.

There are 5 supported ways to attach additional IAM policies to IAM role used by Step Function:

  1. policy_json - JSON string or heredoc, when attach_policy_json = true.
  2. policy_jsons - List of JSON strings or heredoc, when attach_policy_jsons = true and number_of_policy_jsons > 0.
  3. policy - ARN of existing IAM policy, when attach_policy = true.
  4. policies - List of ARNs of existing IAM policies, when attach_policies = true and number_of_policies > 0.
  5. policy_statements - Map of maps to define IAM statements which will be generated as IAM policy. Requires attach_policy_statements = true. See examples/complete for more information.

Conditional creation

Sometimes you need to have a way to create resources conditionally, so the solution is to specify create arguments.

module "step_function" {
  source = "terraform-aws-modules/step-functions/aws"

  create      = false # to disable all resources
  create_role = false  # to control creation of the IAM role and policies required for Step Function

  # ... omitted
}

Examples

  • Complete - Create Step Function and required IAM resources in various combinations with all supported features.

Requirements

Name Version
terraform >= 1.0
aws >= 5.61

Providers

Name Version
aws >= 5.61

Modules

No modules.

Resources

Name Type
aws_cloudwatch_log_group.sfn resource
aws_iam_policy.additional_inline resource
aws_iam_policy.additional_json resource
aws_iam_policy.additional_jsons resource
aws_iam_policy.logs resource
aws_iam_policy.service resource
aws_iam_policy_attachment.additional_inline resource
aws_iam_policy_attachment.additional_json resource
aws_iam_policy_attachment.additional_jsons resource
aws_iam_policy_attachment.logs resource
aws_iam_policy_attachment.service resource
aws_iam_role.this resource
aws_iam_role_policy_attachment.additional_many resource
aws_iam_role_policy_attachment.additional_one resource
aws_sfn_state_machine.this resource
aws_caller_identity.current data source
aws_cloudwatch_log_group.sfn data source
aws_iam_policy_document.additional_inline data source
aws_iam_policy_document.assume_role data source
aws_iam_policy_document.logs data source
aws_iam_policy_document.service data source
aws_region.current data source

Inputs

Name Description Type Default Required
attach_cloudwatch_logs_policy Controls whether CloudWatch Logs policy should be added to IAM role for Lambda Function bool true no
attach_policies Controls whether list of policies should be added to IAM role bool false no
attach_policies_for_integrations Whether to attach AWS Service policies to IAM role bool true no
attach_policy Controls whether policy should be added to IAM role bool false no
attach_policy_json Controls whether policy_json should be added to IAM role bool false no
attach_policy_jsons Controls whether policy_jsons should be added to IAM role bool false no
attach_policy_statements Controls whether policy_statements should be added to IAM role bool false no
aws_region_assume_role Name of AWS regions where IAM role can be assumed by the Step Function string "" no
cloudwatch_log_group_kms_key_id The ARN of the KMS Key to use when encrypting log data. string null no
cloudwatch_log_group_name Name of Cloudwatch Logs group name to use. string null no
cloudwatch_log_group_retention_in_days Specifies the number of days you want to retain log events in the specified log group. Possible values are: 1, 3, 5, 7, 14, 30, 60, 90, 120, 150, 180, 365, 400, 545, 731, 1827, and 3653. number null no
cloudwatch_log_group_tags A map of tags to assign to the resource. map(string) {} no
create Whether to create Step Function resource bool true no
create_role Whether to create IAM role for the Step Function bool true no
definition The Amazon States Language definition of the Step Function string "" no
encryption_configuration Defines what encryption configuration is used to encrypt data in the State Machine. any {} no
logging_configuration Defines what execution history events are logged and where they are logged map(string) {} no
name The name of the Step Function string "" no
number_of_policies Number of policies to attach to IAM role number 0 no
number_of_policy_jsons Number of policies JSON to attach to IAM role number 0 no
policies List of policy statements ARN to attach to IAM role list(string) [] no
policy An additional policy document ARN to attach to IAM role string null no
policy_json An additional policy document as JSON to attach to IAM role string null no
policy_jsons List of additional policy documents as JSON to attach to IAM role list(string) [] no
policy_path Path of IAM policies to use for Step Function string null no
policy_statements Map of dynamic policy statements to attach to IAM role any {} no
publish Determines whether to set a version of the state machine when it is created. bool false no
role_arn The Amazon Resource Name (ARN) of the IAM role to use for this Step Function string "" no
role_description Description of IAM role to use for Step Function string null no
role_force_detach_policies Specifies to force detaching any policies the IAM role has before destroying it. bool true no
role_name Name of IAM role to use for Step Function string null no
role_path Path of IAM role to use for Step Function string null no
role_permissions_boundary The ARN of the policy that is used to set the permissions boundary for the IAM role used by Step Function string null no
role_tags A map of tags to assign to IAM role map(string) {} no
service_integrations Map of AWS service integrations to allow in IAM role policy any {} no
sfn_state_machine_timeouts Create, update, and delete timeout configurations for the step function. map(string) {} no
tags Maps of tags to assign to the Step Function map(string) {} no
trusted_entities Step Function additional trusted entities for assuming roles (trust relationship) list(string) [] no
type Determines whether a Standard or Express state machine is created. The default is STANDARD. Valid Values: STANDARD | EXPRESS string "STANDARD" no
use_existing_cloudwatch_log_group Whether to use an existing CloudWatch log group or create new bool false no
use_existing_role Whether to use an existing IAM role for this Step Function bool false no

Outputs

Name Description
cloudwatch_log_group_arn The ARN of the CloudWatch log group created for the Step Function
cloudwatch_log_group_name The name of the CloudWatch log group created for the Step Function
role_arn The ARN of the IAM role created for the Step Function
role_name The name of the IAM role created for the Step Function
state_machine_arn The ARN of the Step Function
state_machine_creation_date The date the Step Function was created
state_machine_id The ARN of the Step Function
state_machine_name The Name of the Step Function
state_machine_status The current status of the Step Function
state_machine_version_arn The ARN of state machine version

Authors

Module managed by Anton Babenko. Check out serverless.tf to learn more about doing serverless with Terraform.

Please reach out to Betajob if you are looking for commercial support for your Terraform, AWS, or serverless project.

License

Apache 2 Licensed. See LICENSE for full details.