template.yaml

# This is in conversation with emphasizing the null functional difference
# of smart contracts and serverless architectures. Suppostion: smart
# contracts are popular because you don't have to run servers
# This solution provides a functional-facsimile to the developer at
# $0.00 cost as a result of the economies of scale of the services this
# portable architecture (Serverless Application Model [SAM]) provides.
AWSTemplateFormatVersion: '2010-09-09'
Transform: AWS::Serverless-2016-10-31
Description: >-
  XRPL-Price-Persist-Oracle
  https://github.com/yyolk/xrpl-price-persist-oracle

Parameters:
  ScheduleInterval:
    Type: Number
    Description: >-
      Frequency in minutes
    Default: 1
    MinValue: 1
  XRPLNodeJsonRpcUrl:
    Type: String
    Description: >-
      The endpoint to use to connect to the XRPL, this can be a custom node endpoint.
      The default is a Testnet node endpoint, use https://xrplcluster.com (or your own node) for Livenet
    Default: https://s.altnet.rippletest.net:51234/
  XRPLNodeEnvironment:
    Type: String
    Description: >-
      Is this the Testnet or Livenet? This is used for development,
      if the node is in the Testnet the oracle will TrustSet
      to FOO. If on the Livenet, the oracle will TrustSet to USD.
    AllowedValues:
      - Testnet
      - Mainnet
    Default: Testnet
  WalletSecret:
    Type: String
    NoEcho: True
    Description: >-
      This is the wallet seed's secret for persisting the price.
      This wallet's seed will be used to sign transactions.
      For more information see
      https://github.com/yyolk/xrpl-price-persist-oracle-sam#note-on-noecho-cloudformation-parameter-for-wallet-secret-seed
  GitCommit:
    Type: String
    Default: ""
    Description: >-
      This input is fed directly to the function's environment variables that can be deployed publicly.
      This is fed in during deployment (such as a public gh-action) which can then be atomically verified through the public,
      distributed-ledger known as the XRPL

      # This SHA can then be included in the attached memos or as a live endpoint providing it's deployed SHA.
      # This can provide verification through timed events in trustless and public platforms, with the results deployed to the block chain.
      

Conditions:
  # https://docs.aws.amazon.com/lambda/latest/dg/services-cloudwatchevents-expressions.html
  # "For a singular value the unit must be singular (for example, rate(1 day)),
  # otherwise plural (for example, rate(5 days))."
  OneMinute: !Equals
      - !Ref ScheduleInterval
      - 1
 

# More info about Globals: https://github.com/awslabs/serverless-application-model/blob/master/docs/globals.rst
Globals:
  Function:
    # we should always be below this, emprically, this runs at ~30 seconds
    Timeout: 40
    MemorySize: 128


Resources:
  OracleFunction:
    Type: AWS::Serverless::Function
    Properties:
      CodeUri: oracle/
      Handler: contract.handler
      Runtime: python3.9
      Environment:
        Variables:
          WALLET_SECRET: !Ref WalletSecret
          XRPL_JSON_RPC_URL: !Ref XRPLNodeJsonRpcUrl
          XRPL_NODE_ENVIRONMENT: !Ref XRPLNodeEnvironment
          GIT_COMMIT: !Ref GitCommit
      Events:
        OracleInvokeInterval:
          Type: Schedule
          Properties:
            Schedule: !If
              - OneMinute 
              - rate(1 minute)
              - !Sub "rate(${ScheduleInterval} minutes)"
            Description: The interval this function will be invoked
            Enabled: true
      Policies:
        - CloudWatchPutMetricPolicy: {}

Outputs:
  OracleFunction:
    Description: "Oracle Function ARN"
    Value: !GetAtt OracleFunction.Arn
  OracleFunctionIamRole:
    Description: "Implicit IAM Role created for Oracle Function"
    Value: !GetAtt OracleFunctionRole.Arn