module.yml

---
# Copyright 2019 widdix GmbH
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
AWSTemplateFormatVersion: '2010-09-09'
Description: 'cfn-modules: ElastiCache Serverless Valkey'
# cfn-modules:implements(ExposeName, ExposeDnsName)
Parameters:
  VpcModule:
    Description: 'Stack name of vpc module.'
    Type: String
  ClientSgModule:
    Description: 'Stack name of client-sg module.'
    Type: String
  AlertingModule:
    Description: 'Optional but recommended stack name of alerting module.'
    Type: String
    Default: ''
  BastionModule:
    Description: 'Optional but recommended stack name of module implementing Bastion.'
    Type: String
    Default: ''
  KmsKeyModule:
    Description: 'Optional but recommended stack name of kms-key module (ignored when DBSnapshotIdentifier is set, value used from snapshot).'
    Type: String
    Default: ''
  SnapshotRetentionLimit:
    Description: 'The number of days for which ElastiCache retains automatic snapshots before deleting them (set to 0 to disable backups).'
    Type: Number
    Default: 35
    MinValue: 0
    MaxValue: 35
  CacheName:
    Description: 'The unique name for the cache.'
    Type: String
  MaxDataStorageLimit:
    Description: 'The maximum amount of data stored in the cache.'
    Type: 'Number'
    Default: 10
  MaxECPUPerSecondLimit:
    Description: 'Maximum number of ECPU per second. Must be between 1000 and 15000000. You can set the value to zero to remove the limit.'
    Type: 'Number'
    Default: 1000
Conditions:
  HasAlertingModule: !Not [!Equals [!Ref AlertingModule, '']]
  HasBastionModule: !Not [!Equals [!Ref BastionModule, '']]
  HasKmsKeyModule: !Not [!Equals [!Ref KmsKeyModule, '']]
Resources:
  SecurityGroup:
    Type: 'AWS::EC2::SecurityGroup'
    Properties:
      GroupDescription: !Ref 'AWS::StackName'
      VpcId: {'Fn::ImportValue': !Sub '${VpcModule}-Id'}
      SecurityGroupIngress:
      - IpProtocol: tcp
        FromPort: 6379
        ToPort: 6379
        SourceSecurityGroupId: {'Fn::ImportValue': !Sub '${ClientSgModule}-SecurityGroupId'}
  SecurityGroupInSSHBastion:
    Type: 'AWS::EC2::SecurityGroupIngress'
    Condition: HasBastionModule
    Properties:
      GroupId: !Ref SecurityGroup
      IpProtocol: tcp
      FromPort: 6379
      ToPort: 6379
      SourceSecurityGroupId: {'Fn::ImportValue': !Sub '${BastionModule}-SecurityGroupId'}
  ServerlessCache:
    Type: 'AWS::ElastiCache::ServerlessCache'
    Properties:
      CacheUsageLimits:
        DataStorage:
          Unit: 'GB'
          Maximum: !Ref MaxDataStorageLimit
        ECPUPerSecond:
          Maximum: !Ref MaxECPUPerSecondLimit
      DailySnapshotTime: '03:00'
      Engine: 'valkey'
      KmsKeyId: !If [HasKmsKeyModule, {'Fn::ImportValue': !Sub '${KmsKeyModule}-Arn'}, !Ref 'AWS::NoValue']
      SecurityGroupIds:
      - !Ref SecurityGroup
      ServerlessCacheName: !Ref CacheName
      SnapshotRetentionLimit: !Ref SnapshotRetentionLimit
      SubnetIds: !Split [',', {'Fn::ImportValue': !Sub '${VpcModule}-SubnetIdsPrivate'}]
  BytesUsedForCacheAlarm:
    Condition: HasAlertingModule
    Type: 'AWS::CloudWatch::Alarm'
    Properties:
      AlarmActions:
      - 'Fn::ImportValue': !Sub '${AlertingModule}-Arn'
      AlarmDescription: '80% of maximum data storage limit reached.'
      OKActions:
      - 'Fn::ImportValue': !Sub '${AlertingModule}-Arn'
      EvaluationPeriods: 1
      ComparisonOperator: GreaterThanThreshold
      Threshold: !Ref MaxDataStorageLimit
      Metrics:
      - Id: 'o'
        Expression: 'm*0.8'
      - Id: 'm'
        MetricStat:
          Metric:
            Namespace: 'AWS/ElastiCache'
            MetricName: 'BytesUsedForCache'
            Dimensions:
            - Name: 'clusterId'
              Value: !Ref CacheName
          Unit: 'Gigabytes'
          Period: 900
          Stat: 'Max'
  ElastiCacheProcessingUnitsAlarm:
    Condition: HasAlertingModule
    Type: 'AWS::CloudWatch::Alarm'
    Properties:
      AlarmActions:
      - 'Fn::ImportValue': !Sub '${AlertingModule}-Arn'
      AlarmDescription: '80% of maximum procession units reached.'
      OKActions:
      - 'Fn::ImportValue': !Sub '${AlertingModule}-Arn'
      EvaluationPeriods: 1
      ComparisonOperator: GreaterThanThreshold
      Threshold: !Ref MaxECPUPerSecondLimit
      Metrics:
      - Id: 'o'
        Expression: 'm/900*0.8'
      - Id: 'm'
        MetricStat:
          Metric:
            Namespace: 'AWS/ElastiCache'
            MetricName: 'ElastiCacheProcessingUnits'
            Dimensions:
            - Name: 'clusterId'
              Value: !Ref CacheName
          Period: 900
          Stat: 'SUM'
Outputs:
  ModuleId:
    Value: 'elasticache-serverless'
  ModuleVersion:
    Value: '0.2.0'
  StackName:
    Value: !Ref 'AWS::StackName'
  Name:
    Description: 'The name of the cluster'
    Value: !Ref CacheName
    Export:
      Name: !Sub '${AWS::StackName}-Name'
  DnsName:
    Description: 'The DNS address of the Serverless cache.'
    Value: !GetAtt 'ServerlessCache.Endpoint.Address'
    Export:
      Name: !Sub '${AWS::StackName}-DnsName'