【サンプルコード】AWS SAMでAWS StepFunctionsからAmazon ECS on Fargateのタスクを起動する

samconfig.toml

# More information about the configuration file can be found here:
# https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/serverless-sam-cli-config.html
version = 0.1

[default]
[default.global.parameters]
stack_name = "sam-app"

[default.build.parameters]
cached = true
parallel = true

[default.validate.parameters]
lint = true

[default.deploy.parameters]
capabilities = "CAPABILITY_IAM CAPABILITY_NAMED_IAM CAPABILITY_AUTO_EXPAND"
confirm_changeset = true
resolve_s3 = true
parameter_overrides = [
    "ClusterArn=xxx",
    "TaskDefinitionArn=xxx",
    "ContainerName=xxx",
    "SubnetId=xxx",
    "SecurityGroupId=xxx",
    "TaskExecutionRoleArn=xxx",
    "TaskRoleArn=xxx"
]


[default.package.parameters]
resolve_s3 = true

[default.sync.parameters]
watch = true

[default.local_start_api.parameters]
warm_containers = "EAGER"

[default.local_start_lambda.parameters]
warm_containers = "EAGER"

stock_trader.asl.json

{
	"Comment": "A state machine that does mock stock trading.",
	"StartAt": "Check Stock Value",
	"States": {
		"Check Stock Value": {
			"Type": "Task",
			"Resource": "${StockCheckerFunctionArn}",
			"Retry": [
				{
					"ErrorEquals": [
						"States.TaskFailed"
					],
					"IntervalSeconds": 15,
					"MaxAttempts": 5,
					"BackoffRate": 1.5
				}
			],
			"Next": "Buy or Sell?"
		},
		"Buy or Sell?": {
			"Type": "Choice",
			"Choices": [
				{
					"Variable": "$.stock_price",
					"NumericLessThanEquals": 50,
					"Next": "Buy Stock"
				}
			],
			"Default": "Sell Stock"
		},
		"Sell Stock": {
			"Type": "Task",
			"Resource": "${StockSellerFunctionArn}",
			"Retry": [
				{
					"ErrorEquals": [
						"States.TaskFailed"
					],
					"IntervalSeconds": 2,
					"MaxAttempts": 3,
					"BackoffRate": 1
				}
			],
			"Next": "Record Transaction"
		},
		"Buy Stock": {
			"Type": "Task",
			"Resource": "${StockBuyerFunctionArn}",
			"Retry": [
				{
					"ErrorEquals": [
						"States.TaskFailed"
					],
					"IntervalSeconds": 2,
					"MaxAttempts": 3,
					"BackoffRate": 1
				}
			],
			"Next": "Record Transaction"
		},
		"Record Transaction": {
			"Type": "Task",
			"Resource": "${DDBPutItem}",
			"Parameters": {
				"TableName": "${DDBTable}",
				"Item": {
					"Id": {
						"S.$": "$.id"
					},
					"Type": {
						"S.$": "$.type"
					},
					"Price": {
						"N.$": "$.price"
					},
					"Quantity": {
						"N.$": "$.qty"
					},
					"Timestamp": {
						"S.$": "$.timestamp"
					}
				}
			},
			"Retry": [
				{
					"ErrorEquals": [
						"States.TaskFailed"
					],
					"IntervalSeconds": 20,
					"MaxAttempts": 5,
					"BackoffRate": 10
				}
			],
			"Next": "Run ECS task"
		},
		"Run ECS task": {
			"Type": "Task",
			"Resource": "arn:aws:states:::ecs:runTask.sync",
			"Parameters": {
				"LaunchType": "FARGATE",
				"Cluster": "${ClusterArn}",
				"TaskDefinition": "${TaskDefinitionArn}",
				"NetworkConfiguration": {
					"AwsvpcConfiguration": {
						"AssignPublicIp": "ENABLED",
						"SecurityGroups": [
							"${SecurityGroupId}"
						],
						"Subnets": [
							"${SubnetId}"
						]
					}
				},
				"Overrides": {
					"ContainerOverrides": [
						{
							"Name": "${ContainerName}",
                            "Command": [
                                "--arg1",
                                "200",
                                "--arg2",
                                "200"
                            ]
						}
					]
				}
			},
			"Next": "Success",
			"Catch": [
				{
					"ErrorEquals": [
						"States.TaskFailed"
					],
					"Next": "Error"
				}
			]
		},
		"Success": {
			"Type": "Pass",
			"Comment": "Success",
			"End": true
		},
		"Error": {
			"Type": "Pass",
			"Comment": "Error",
			"End": true
		}
	}
}

template.yaml

AWSTemplateFormatVersion: "2010-09-09"
Transform: AWS::Serverless-2016-10-31
Description: >
  sam-app

  Sample SAM Template for sam-app


Parameters:
  ClusterArn:
    Type: String
  TaskDefinitionArn:
    Type: String
  ContainerName:
    Type: String
  SubnetId:
    Type: String
  SecurityGroupId:
    Type: String
  TaskExecutionRoleArn:
    Type: String
  TaskRoleArn:
    Type: String

Resources:
  StockTradingStateMachine:
    Type: AWS::Serverless::StateMachine # More info about State Machine Resource: https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-resource-statemachine.html
    Properties:
      Name: StockTradingStateMachine # Add
      DefinitionUri: statemachine/stock_trader.asl.json
      DefinitionSubstitutions:
        StockCheckerFunctionArn: !GetAtt StockCheckerFunction.Arn
        StockSellerFunctionArn: !GetAtt StockSellerFunction.Arn
        StockBuyerFunctionArn: !GetAtt StockBuyerFunction.Arn
        DDBPutItem: !Sub arn:${AWS::Partition}:states:::dynamodb:putItem
        DDBTable: !Ref TransactionTable
        ClusterArn: !Ref ClusterArn # Add
        ContainerName: !Ref ContainerName # Add
        TaskDefinitionArn: !Ref TaskDefinitionArn # Add
        SubnetId: !Ref SubnetId # Add
        SecurityGroupId: !Ref SecurityGroupId # Add
      Role: !GetAtt StockTradingStateMachineRole.Arn # Modify

  StockCheckerFunction:
    Type: AWS::Serverless::Function # More info about Function Resource: https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-resource-function.html
    Properties:
      CodeUri: functions/stock_checker/
      Handler: app.lambda_handler
      Runtime: python3.10
      Architectures:
        - x86_64

  StockSellerFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: functions/stock_seller/
      Handler: app.lambda_handler
      Runtime: python3.10
      Architectures:
        - x86_64

  StockBuyerFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: functions/stock_buyer/
      Handler: app.lambda_handler
      Runtime: python3.10
      Architectures:
        - x86_64

  TransactionTable:
    Type: AWS::Serverless::SimpleTable # More info about SimpleTable Resource: https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-resource-simpletable.html
    Properties:
      PrimaryKey:
        Name: Id
        Type: String
      ProvisionedThroughput:
        ReadCapacityUnits: 1
        WriteCapacityUnits: 1

  #----------------------------------------
  # IAM Role
  #----------------------------------------      
  StockTradingStateMachineRole:
    Type: AWS::IAM::Role
    Properties:
      RoleName: StockTradingStateMachineRole
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Principal:
              Service:
                - states.amazonaws.com
            Action: sts:AssumeRole
      Policies:
        - PolicyName:  TaskRunnerStateMachinePolicy
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              - Effect: Allow
                Action:
                  - ecs:RunTask
                Resource: 
                  - !Ref TaskDefinitionArn
              - Effect: Allow
                Action:
                  - ecs:StopTask
                  - ecs:DescribeTasks
                Resource: 
                  - "*"
              - Effect: Allow
                Action:
                  - events:PutTargets
                  - events:PutRule
                  - events:DescribeRule
                Resource:
                  - !Sub arn:aws:events:${AWS::Region}:${AWS::AccountId}:rule/StepFunctionsGetEventsForECSTaskRule
              - Effect: Allow
                Action:
                  - iam:PassRole
                Resource: 
                  - !Ref TaskExecutionRoleArn
                  - !Ref TaskRoleArn
              - Effect: Allow
                Action:
                  - lambda:InvokeFunction
                Resource: 
                  - !GetAtt StockCheckerFunction.Arn
                  - !GetAtt StockSellerFunction.Arn
                  - !GetAtt StockBuyerFunction.Arn
              - Effect: Allow
                Action:
                  - dynamodb:PutItem
                  - dynamodb:UpdateItem
                  - dynamodb:BatchWriteItem
                Resource: 
                  - !GetAtt TransactionTable.Arn

Outputs:
  # StockTradingStateMachineHourlyTradingSchedule is an implicit Schedule event rule created out of Events key under Serverless::StateMachine
  # Find out more about other implicit resources you can reference within SAM
  # https://docs.aws.amazon.com/serverless-application-model/latest/developerguide/sam-specification-generated-resources.html
  StockTradingStateMachineArn:
    Description: "Stock Trading State machine ARN"
    Value: !Ref StockTradingStateMachine
  StockTradingStateMachineRoleArn:
    Description: "IAM Role created for Stock Trading State machine based on the specified SAM Policy Templates"
    Value: !GetAtt StockTradingStateMachineRole.Arn