SecretsManager secretStringTemplate not using variable

[nabeelvalley]

Hi, I'm trying to generate some credentials using SecretsManager but it seems to not be behaving as expected:

I am using the following code to generate a secret:

new sm.Secret(this, "DBAdminCredentials", {
      generateSecretString: {
        secretStringTemplate: JSON.stringify({
          username: this.dbUsername,
        }),
        generateStringKey: "password",
      },
    });

Where this.dbUsername is defined at a class level:

public readonly dbUsername = "dbusername";

According to my understanding the username should be present in the secret, but the resulting object is this (Via SecretsManager in the Console):

{
    "password": "xxxxxxxxxx"
}

However, if I don't use the variable and put the username straight into the template it works fine:

new sm.Secret(this, "DBAdminCredentials", {
      generateSecretString: {
        secretStringTemplate: JSON.stringify({
          username: "dbusername",
        }),
        generateStringKey: "password",
      },
    });

I've also noticed a similar issue with the id passed to sm.Secret, but I have not investigated as completely

Not sure if this is a bug or expected behaviour - does this also apply to other constructs too - it's not what I would expect to happen in this context

[peterwoodworth]

Is it possible that this.dbUsername refers to a token when this behavior occurs? Or are you actually strictly hardcoding it as described