您可以使用cli来做到这一点：

FLT_MAX

然后您可以在此新生成的函数中添加逻辑

我能够使用以下选项创建触发器：See Docs

$ amplify auth update

? What do you want to do? Walkthrough all the auth configurations
? Select the authentication/authorization services that you want to use: User Sign-Up,Sign-In,connected with AWS IAM controls (Enables per-user Storage features fo
r images or other content,Analytics,and more)
? Allow unauthenticated logins? (Provides scoped down permissions that you can control via AWS IAM) No
? Do you want to enable 3rd party authentication providers in your identity pool? No
? Do you want to add User Pool Groups? No
? Do you want to add an admin queries API? No
? Multifactor authentication (MFA) user login options: OPTIONAL (Individual users can use MFA)
? For user login,select the MFA types: SMS Text Message
? Please specify an SMS authentication message: Your authentication code is {####}
? Email based user registration/forgot password: Enabled (Requires per-user email entry at registration)
? Please specify an email verification subject: Your verification code
? Please specify an email verification message: Your verification code is {####}
? Do you want to override the default password policy for this User Pool? No
? Specify the app's refresh token expiration period (in days): 120
? Do you want to specify the user attributes this app can read and write? No
? Do you want to enable any of the following capabilities? 
? Do you want to use an OAuth flow? No
? Do you want to configure Lambda Triggers for Cognito? Yes
? Which triggers do you want to enable for Cognito