Is it possible to run a lambda as part of a deployment? So I could say something to effect of this psuedo resource:

Service(..., dependsOn: migrationLambdaRun)

Edit: Found the command package 🙂

There's also https://github.com/pulumi/pulumi/issues/2545 which would allow you to call your lambda inside an Output.Apply and then wait for that. But for now the command package is probably the best choice.