AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: 'AWS ParallelCluster API'

Parameters:
  Region:
    Description: When set to a given region name (e.g. eu-west-1), the API can control resources in that region only. Set to '*' to control all regions.
    Type: String
    Default: '*'

  ParallelClusterFunctionRole:
    Description: |
      When specified, the ARN of the execution role for the ParallelCluster Lambda function
    Type: String
    Default: ''

  ApiDefinitionS3Uri:
    Description: S3 URI of the ParallelCluster API spec
    Type: String
    Default: s3://<REGION>-aws-parallelcluster/parallelcluster/3.8.0/api/ParallelCluster.openapi.yaml

  CustomDomainName:
    Description: When specified, the custom domain name of the ParallelCluster API. Requires specifying a custom domain certificate
    Type: String
    Default: ''

  CustomDomainCertificate:
    Description: When specified, the ARN of the certificate for the custom domain name of the ParallelCluster API. Required when specifying a custom domain name
    Type: String
    Default: ''

  CustomDomainHostedZoneId:
    Description: When specified, the id of the Hosted Zone where the custom domain record of the ParallelCluster API is registered
    Type: String
    Default: ''

  PoliciesTemplateUri:
    Description: "S3 URI of the ParallelCluster Policies Template. Defaults to: s3://<REGION>-aws-parallelcluster/parallelcluster/3.8.0/templates/policies/policies.yaml"
    Type: String
    Default: ''

  VpcEndpointId:
    Description: When specified, configure a private API with the specified endpoint
    Type: String
    Default: ''

  EnableIamAdminAccess:
    Description: |
      When set to true the ParallelCluster API takes care of IAM resource creation when deploying clusters or generating custom AMIs.
      WARNING - setting this to true grants IAM admin privileges to the Lambda function
    Type: String
    Default: false
    AllowedValues:
      - true
      - false

  EnableFSxS3Access:
    Description: |
      When set to true the ParallelCluster API can access, write to the S3 buckets specified in the Filed FsxS3Bucket, it is needed to import/export from/to S3 when creating an FSx filesystem.
      NOTE - setting this to true grants the Lambda function S3 Get*, List* and PutObject privileges on the buckets specified in FsxS3Buckets.
    Type: String
    Default: false
    AllowedValues:
      - true
      - false

  FsxS3Buckets:
    Description: |
      Comma separated list of S3 bucket ARNs, to allow the lambda function to import/export from/to S3 when creating an FSx filesystem.
      NOTE - The setting is used only when EnableFSxS3Access is set to true. (example arn:aws:s3:::<S3_BUCKET_1>,arn:aws:s3:::<S3_BUCKET_2>)
    Type: String
    Default: ''
    AllowedPattern: ^((arn:[a-z\-\*]*:s3:[a-z0-9\-]*:([0-9]{12})*:[^,\s\/]+)?(,arn:[a-z\-\*]*:s3:[a-z0-9\-]*:([0-9]{12})*:[^,\s\/]+)*)$|^\*$
    ConstraintDescription: |
      The list of S3 buckets is incorrectly formatted. The list should have the format: arn:<PARTITION>:s3:<REGION>:<ACCOUNT_ID>:<BUCKET_NAME>[,arn:<PARTITION>:s3:<REGION>:<ACCOUNT_ID>:<BUCKET_NAME>,...]
      Example: arn:aws:s3:::test-bucket-1,arn:aws:s3:::test-bucket-2,arn:aws:s3:::test-bucket-3

  PermissionsBoundaryPolicy:
    Description: |
      ARN of a IAM policy to use as PermissionsBoundary for all IAM resources created by ParallelCluster API.
      When specified, IAM permissions assumed by the API are conditionally restricted to the usage of the given PermissionsBoundary
    Type: String
    Default: ''

  CreateApiUserRole:
    Description: Creates a IAM role authorized to invoke the API. The Api is configured with a resource based policy to grant invoke permission to the created user only.
    Type: String
    Default: true
    AllowedValues:
      - true
      - false

  CustomBucket:
    Description: (Debug only) bucket to retrieve S3 artifacts for internal resources.
    Type: String
    Default: ''

Mappings:
  ParallelCluster:
    Constants:
      Version: 3.8.0  # major.minor.patch+alpha/beta_identifier
      ShortVersion: 3.8.0  # major.minor.patch
      Stage: prod


# More info about Globals: https://github.com/awslabs/serverless-application-model/blob/master/docs/globals.rst
Globals:
  Function:
    Timeout: 30
    Tags:
      'parallelcluster:version': !FindInMap [ParallelCluster, Constants, Version]

  Api:
    Auth:
      DefaultAuthorizer: AWS_IAM
      ResourcePolicy:
        CustomStatements:
          Effect: 'Deny'
          Action: 'execute-api:Invoke'
          Resource: ['execute-api:/*/*/*']
          Principal: '*'
          Condition:
            StringNotLike:
              # This allows also creds assumed through sts for the ParallelClusterApiUserRole role
              aws:PrincipalArn: !If
                - CreateApiUserRoleCondition
                - !Sub
                  - arn:${AWS::Partition}:*::${AWS::AccountId}:*/ParallelClusterApiUserRole-${StackIdSuffix}*
                  - { StackIdSuffix: !Select [2, !Split ['/', !Ref 'AWS::StackId']] }
                - '*'
    TracingEnabled: True
    EndpointConfiguration:
      Type: REGIONAL
    MethodSettings:
      - HttpMethod: '*'
        ResourcePath: '/*'
        ThrottlingRateLimit: 100
        ThrottlingBurstLimit: 10
        MetricsEnabled: true

Conditions:
  UseCustomParallelClusterFunctionRole: !Not [!Equals [!Ref ParallelClusterFunctionRole, '']]
  CreateIamResources: !Not [!Condition UseCustomParallelClusterFunctionRole]
  UseCustomDomain: !Not [!Equals [!Ref CustomDomainName, '']]
  UseRoute53Configuration: !Not [!Equals [!Ref CustomDomainHostedZoneId, '']]
  UseCustomDomainAndRoute53Configuration: !And
    - !Condition UseCustomDomain
    - !Condition UseRoute53Configuration
  UsePrivateVpcEndpoint: !And
    - !Not [!Condition UseCustomDomainAndRoute53Configuration]
    - !Not [!Equals [!Ref VpcEndpointId, '']]
  DoNotUseCustomDomain: !And
    - !Not [!Condition UsePrivateVpcEndpoint]
    - !Not [!Condition UseCustomDomainAndRoute53Configuration]
  CreateApiUserRoleCondition: !Equals [!Ref CreateApiUserRole, true]
  UseCustomBucket: !Not [!Equals [!Ref CustomBucket, '']]
  UseCustomPoliciesTemplateUri: !Not [!Equals [!Ref PoliciesTemplateUri, '']]

Resources:
  # Policies nested stack
  PclusterPolicies:
    Type: AWS::CloudFormation::Stack
    Condition: CreateIamResources
    Properties:
      TemplateURL: !If
        - UseCustomPoliciesTemplateUri
        - !Ref PoliciesTemplateUri
        - !Sub
          - "https://${AWS::Region}-aws-parallelcluster.s3.${AWS::Region}.${AWS::URLSuffix}/parallelcluster/${Version}/templates/policies/policies.yaml"
          - { Version: !FindInMap [ParallelCluster, Constants, Version] }
      TimeoutInMinutes: 10
      Parameters:
        Region: !Ref Region
        EnableFSxS3Access: !Ref EnableFSxS3Access
        EnableIamAdminAccess: !Ref EnableIamAdminAccess
        FsxS3Buckets: !Ref FsxS3Buckets
        PermissionsBoundaryPolicy: !Ref PermissionsBoundaryPolicy
        EnableBatchAccess: true

  PclusterLayer:
    Type: AWS::Lambda::LayerVersion
    Properties:
      LayerName: !Sub
        - PCLayer-${StackIdSuffix}
        - { StackIdSuffix: !Select [2, !Split ['/', !Ref 'AWS::StackId']] }
      Description: Library which contains aws-parallelcluster python package and dependencies
      Content:
        S3Bucket: !If [ UseCustomBucket, !Ref CustomBucket, !Sub "${AWS::Region}-aws-parallelcluster" ]
        S3Key: !Sub
          - parallelcluster/${Version}/layers/aws-parallelcluster/lambda-layer.zip
          - { Version: !FindInMap [ParallelCluster, Constants, Version]}
      CompatibleRuntimes:
        - python3.9

  # We need to define three AWS::Serverless::Api due to an issue with the handling of AWS::NoValue
  # See related GitHub issue: https://github.com/aws/serverless-application-model/issues/1435
  ApiGatewayApiWithCustomDomainAndRoute53Configuration:
    Condition: UseCustomDomainAndRoute53Configuration
    Type: AWS::Serverless::Api
    Properties:
      Tags:
        'parallelcluster:version': !FindInMap [ParallelCluster, Constants, Version]
      StageName: !FindInMap [ParallelCluster, Constants, Stage]
      DefinitionBody:
        Fn::Transform:
          Name: AWS::Include
          Parameters:
            Location: !Ref ApiDefinitionS3Uri
      Domain:
        DomainName: !Ref CustomDomainName
        CertificateArn: !Ref CustomDomainCertificate
        Route53:
          HostedZoneId: !Ref CustomDomainHostedZoneId

  ApiGatewayApiWithoutCustomDomain:
    Condition: DoNotUseCustomDomain
    Type: AWS::Serverless::Api
    Properties:
      Tags:
        'parallelcluster:version': !FindInMap [ParallelCluster, Constants, Version]
      StageName: !FindInMap [ParallelCluster, Constants, Stage]
      DefinitionBody:
        Fn::Transform:
          Name: AWS::Include
          Parameters:
            Location: !Ref ApiDefinitionS3Uri

  ApiGatewayApiWithPrivateVpcEndpoint:
    Condition: UsePrivateVpcEndpoint
    Type: AWS::Serverless::Api
    Properties:
      Tags:
        'parallelcluster:version': !FindInMap [ParallelCluster, Constants, Version]
      StageName: !FindInMap [ParallelCluster, Constants, Stage]
      DefinitionBody:
        Fn::Transform:
          Name: AWS::Include
          Parameters:
            Location: !Ref ApiDefinitionS3Uri
      EndpointConfiguration:
        Type: PRIVATE
        VPCEndpointIds: [!Ref VpcEndpointId]
      Auth:
        DefaultAuthorizer: AWS_IAM
        ResourcePolicy:
          IntrinsicVpceWhitelist: [!Ref VpcEndpointId]

  # Note that even for Chinese regions here we need to use apigateway.amazonaws.com instead of apigateway.amazonaws.com.cn
  APIGatewayExecutionRole:
   Type: AWS::IAM::Role
   Properties:
     AssumeRolePolicyDocument:
       Version: 2012-10-17
       Statement:
         - Effect: Allow
           Principal:
             Service:
               - apigateway.amazonaws.com
           Action:
             - 'sts:AssumeRole'
     Policies:
       - PolicyName: lambda-invoke
         PolicyDocument:
           Version: '2012-10-17'
           Statement:
             - Effect: Allow
               Action: lambda:InvokeFunction
               Resource: !GetAtt ParallelClusterFunction.Arn

  ParallelClusterFunction:
    Type: AWS::Lambda::Function
    Properties:
      TracingConfig:
        Mode: Active
      MemorySize: 2048
      Timeout: 30
      Role: !If [UseCustomParallelClusterFunctionRole, !Ref ParallelClusterFunctionRole, !GetAtt [ PclusterPolicies, Outputs.ParallelClusterLambdaRoleArn ]]
      Tags:
        - Key: 'parallelcluster:resource'
          Value: api
        - Key: 'parallelcluster:version'
          Value: !FindInMap [ParallelCluster, Constants, Version]
      Runtime: python3.9
      Handler: pcluster.api.awslambda.entrypoint.lambda_handler
      Layers:
        - !Ref PclusterLayer
      # Lambda fails creation without specifying a non-empty code or container
      Code:
        ZipFile: " "

  ParallelClusterApiUserRole:
    Type: AWS::IAM::Role
    Condition: CreateApiUserRoleCondition
    Properties:
      RoleName:  !Sub
        - ParallelClusterApiUserRole-${StackIdSuffix}
        - { StackIdSuffix: !Select [2, !Split ['/', !Ref 'AWS::StackId']] }
      AssumeRolePolicyDocument:
        Statement:
          - Effect: Allow
            Action: sts:AssumeRole
            Principal:
              AWS:
                - !Sub arn:${AWS::Partition}:iam::${AWS::AccountId}:root
      Policies:
        - PolicyName: ParallelClusterApiInvokePolicy
          PolicyDocument:
            Statement:
              - Action:
                  - execute-api:Invoke
                Effect: Allow
                Resource: !Sub
                  - arn:${AWS::Partition}:execute-api:${AWS::Region}:${AWS::AccountId}:${ApiId}/*/*/*
                  - ApiId: !If
                    - UseCustomDomainAndRoute53Configuration
                    - !Ref ApiGatewayApiWithCustomDomainAndRoute53Configuration
                    - !If
                      - UsePrivateVpcEndpoint
                      - !Ref ApiGatewayApiWithPrivateVpcEndpoint
                      - !Ref ApiGatewayApiWithoutCustomDomain
            Version: '2012-10-17'

  ### -----------

  ParallelClusterFunctionLogGroup:
    Type: AWS::Logs::LogGroup
    Properties:
      LogGroupName: !Sub /aws/lambda/${ParallelClusterFunction}
      RetentionInDays: 30

Outputs:
  ParallelClusterLambdaArn:
    Description: 'ARN of the ParallelCluster Lambda function'
    Value: !GetAtt ParallelClusterFunction.Arn

  ParallelClusterApiInvokeUrl:
    Description: 'Url to reach the API endpoint'
    Export:
      Name: !Sub ${AWS::StackName}-ParallelClusterApiInvokeUrl
    Value: !If
      - UseCustomDomain
      - !Sub
        - https://${CustomDomain}
        - { CustomDomain: !Ref CustomDomainName }
      - !Sub
        - https://${Api}.execute-api.${AWS::Region}.${AWS::URLSuffix}/${StageName}
        - Api: !If
            - UsePrivateVpcEndpoint
            - !Sub
              - '${restApiId}-${vpceId}'
              - { restApiId: !Ref ApiGatewayApiWithPrivateVpcEndpoint, vpceId: !Ref VpcEndpointId }
            - !Ref ApiGatewayApiWithoutCustomDomain
          StageName: !FindInMap [ParallelCluster, Constants, Stage]

  ParallelClusterApiUserRole:
    Condition: CreateApiUserRoleCondition
    Export:
      Name: !Sub ${AWS::StackName}-ParallelClusterApiUserRole
    Description: 'IAM Role with permissions to invoke the ParallelCluster API'
    Value: !GetAtt ParallelClusterApiUserRole.Arn

  ParallelClusterLambdaLogGroup:
    Value: !Ref ParallelClusterFunctionLogGroup
    Description: 'LogGroup for the Lambda function implementing ParallelCluster Api'