我可以在 IoT 规则 SQL 中动态设置条件吗？

Question

in this section of yaml file, I need to update condition in sql statement.

for example, user can reset condition to equal 20 instead of 30.

NotifyTemperatureAlarm:
Type: 'AWS::Serverless::Function'
DependsOn: AlertSNSTopic
Properties:
  CodeUri: src/notify_temperature_alarm/
  Handler: app.lambda_handler
  Runtime: python3.9
  Architectures:
    - x86_64
  Events:
    PutImageEvent:
      Type: IoTRule
      Properties:
        Sql: Select * FROM 'device/temperature/alarms' where value > 30
  Policies:
    Version: "2012-10-17"
    Statement:
      - Effect: Allow
        Action: "sns:*"
        Resource: "*"
  Environment:
    Variables:
      alert_sns: !Ref AlertSNSTopic

Answer 1

make your condition in parameters section such as

Parameters:
TemperatureThreshold:
  Type: Number
  Default: '20'

then update NotifyTemperatureAlarm such as

NotifyTemperatureAlarm:
Type: 'AWS::Serverless::Function'
DependsOn: AlertSNSTopic
Properties:
  CodeUri: src/notify_temperature_alarm/
  Handler: app.lambda_handler
  Runtime: python3.9
  Architectures:
    - x86_64
  Events:
    PutImageEvent:
      Type: IoTRule
      Properties:
        Sql: !Sub "SELECT * FROM 'device/temperature/alarms' where value > ${TemperatureThreshold}"
  Policies:
    Version: "2012-10-17"
    Statement:
      - Effect: Allow
        Action: "sns:*"
        Resource: "*"
  Environment:
    Variables:
      alert_sns: !Ref AlertSNSTopic

to make TemperatureThreshold Adjustable, you can update it from cloudformation such as

client = boto3.client('cloudformation')  

response = client.update_stack(
    StackName = "your_stack_name",
    UsePreviousTemplate = True,
    Capabilities = ['CAPABILITY_IAM'],
    Parameters=[
        {
            'ParameterKey': 'TemperatureThreshold',
            'ParameterValue': str(new_threshold),
        }
    ]
)