What is the process of using Twingate with Google Cloud Functions in TypeScript

Question

Pulumi · Accepted Answer

To use Twingate with Google Cloud Functions, you would typically deploy a Cloud Function that interacts with the Twingate API. You can manage access to the Cloud Function using IAM (Identity and Access Management) to ensure that only authenticated Twingate users or networks can invoke it.

Here is the step-by-step process described in code to create a Google Cloud Function and set IAM policies using Pulumi with TypeScript:

1. **Install the necessary Pulumi GCP package**: You need the `@pulumi/gcp` package installed in your project. You can install it using your package manager, for example by running `npm install @pulumi/gcp`.

2. **Google Cloud Function**: Define a Cloud Function using Pulumi's `gcp.cloudfunctions.Function` resource. You'll also need to supply the source code for your Cloud Function, which you can do by specifying the path to a ZIP archive or a source repository.

3. **IAM Policy for Cloud Function**: Secure the Cloud Function by applying an IAM policy that specifies who or what can invoke the function.

In the following Pulumi TypeScript program, we are creating a Cloud Function, and we'll assume you have the zipped source code for the function ready.

```typescript
import * as pulumi from '@pulumi/pulumi';
import * as gcp from '@pulumi/gcp';

// Define the Cloud Function.
const myFunction = new gcp.cloudfunctions.Function('myFunction', {
    runtime: 'nodejs14', // specify the runtime
    entryPoint: 'handler', // the name of the function within your code
    sourceArchiveBucket: 'my-bucket', // the GCS bucket containing the zipped source code
    sourceArchiveObject: 'source-code.zip', // the object name of the zipped source code
    triggerHttp: true, // indicate that we want to trigger the function via HTTP requests
    // Optional parameters like environment variables, memory, and timeout could be configured here.
});

// Export the function's URL.
export const functionUrl = myFunction.httpsTriggerUrl;

// IAM policy to specify access for the Twingate network.
const iamMember = new gcp.cloudfunctions.FunctionIamMember('myFunctionIamMember', {
    project: myFunction.project, // define the project
    region: myFunction.region, // define the region
    cloudFunction: myFunction.name, // the name of the cloud function
    role: 'roles/cloudfunctions.invoker', // role that allows invocation of the function
    member: 'serviceAccount:your-twinge-connector@your-project-id.iam.gserviceaccount.com', // the service account used by Twingate
});

// Ensure IAM policies are applied after the function is created.
iamMember.dependsOn = [myFunction];
```

In this program:

- We import the `@pulumi/pulumi` and `@pulumi/gcp` modules.
- We create a Cloud Function with specified runtime (e.g., Node.js 14), entry point, source bucket, and source archive.
- We define that the function should be triggered over HTTP.
- We export the URL at which the Cloud Function can be triggered.
- We set an IAM policy on the Cloud Function, granting the "roles/cloudfunctions.invoker" role to the Twingate service account, thus securing it. Make sure to replace `'serviceAccount:your-twinge-connector@your-project-id.iam.gserviceaccount.com'` with your actual Twingate service account.
- We use `dependsOn` to ensure that the IAM Member policy is applied only after the Cloud Function has been created.

Remember to replace placeholders with your specific information, like the bucket name, the source code archive, and the Twingate service account.

To run this Pulumi program, save it in a `index.ts` file in a Pulumi project directory, run `pulumi up`, and follow the prompts. This will provision your Cloud Function along with the called IAM policies on your GCP project. Be sure to have your Pulumi and GCP configurations set up correctly in your environment.