provisioner.ts

// https://github.com/pulumi/examples/blob/master/aws-ts-ec2-provisioners/provisioners/provisioner.ts
// Copyright 2016-2019, Pulumi Corporation.  All rights reserved.

import * as pulumi from "@pulumi/pulumi"
import * as uuid from "uuid"

// Provisioner lets a custom action run the first time a resource has been created. It takes as input
// a dependent property. Anytime its value changes, the resource is replaced and will re-run its logic.
export class Provisioner<T, U> extends pulumi.dynamic.Resource {
    dep: pulumi.Output<T>
    result: pulumi.Output<U>
    constructor(name: string, props: ProvisionerProperties<T, U>, opts?: pulumi.CustomResourceOptions) {
        const provider: pulumi.dynamic.ResourceProvider = {
            diff: async (_: pulumi.ID, olds: State<T, U>, news: State<T, U>) => {
                let replace = false
                let replacementProperties = []
                if (JSON.stringify(olds.dep) !== JSON.stringify(news.dep)) {
                    replace = true
                    replacementProperties.push("dep")
                }
                // Only trigger replacement due to the `changeToken` property, IFF
                // the changeToken still has a value in the new inputs, and it doesn't
                // match with the old value. If, say, the user decides to no longer specify
                // the changeToken in the new inputs, then we don't trigger a replacement.
                if (news.changeToken && olds.changeToken !== news.changeToken) {
                    replace = true
                    replacementProperties.push("changeToken")
                }
                return {
                    changes: replace,
                    replaces: replace ? replacementProperties : undefined,
                    deleteBeforeReplace: true,
                }
            },
            create: async (inputs: State<T, U>) => {
                const result = await props.onCreate(inputs.dep)
                if (result !== undefined) {
                    inputs.result = result
                }
                return { id: uuid.v4(), outs: inputs }
            },
        }
        super(provider, name, { dep: props.dep, changeToken: props.changeToken, result: null }, opts)
    }
}

export interface ProvisionerProperties<T, U> {
    changeToken: pulumi.Input<string>
    dep: pulumi.Input<T>
    onCreate: (dep: pulumi.Unwrap<T>) => Promise<pulumi.Unwrap<U>>
}

interface State<T, U> {
    dep: pulumi.Unwrap<T>
    changeToken: pulumi.Unwrap<string>
    result: pulumi.Unwrap<U>
}