Generate STS token on Google Cloud with PHP

Question

I have a function that I use with AWS to generate tokens to access Kubernetes cluster, I want to create a version of it to work with GCP, but I am confused about the inputs and the classes to be used

Right now I created a service account, and that service account gave me a JSON file that I use it to connect to the cluster and that works just fine. I am looking for a way to generate the token with PHP and without depending on the CLI.

This is the code that I am using with AWS, what would be the equivalent to the code below.

        $validator = Validator::make($paramsArray, [
            'region' => 'required',
            'clusterName' => 'required',
            'accessKeyId' => 'required',
            'secretAccessKey' => 'required'
        ]);

        if ($validator->fails()) {
            foreach($validator->errors()->all() as $error){
                $this->error($error);
                $this->newLine();
            }
            throw new \Exception('Missing required params');
        }        

        $region = $paramsArray['region'];
        $clusterName = $paramsArray['clusterName'];
        $expiry = Carbon::now()->addMinutes(15);
        
        $request = new Request('GET', "https://sts.{$region}.amazonaws.com/?Action=GetCallerIdentity&Version=2011-06-15", [
            'x-k8s-aws-id' => $clusterName,
        ]);
        
        $signer = new SignatureV4('sts', $region, []);
        $credentialsProvider = CredentialProvider::fromCredentials(new Credentials($paramsArray['accessKeyId'], $paramsArray['secretAccessKey']))()->wait();
        $signature = $signer->presign($request, $credentialsProvider, $expiry);        
        // @see https://github.com/aws/aws-cli/commit/3ef2a3cf895cb64cf45a28284ca3291cd1c33755
        $token = 'k8s-aws-v1.'.rtrim(base64_encode($signature->getUri()), '='); 

I did try a similar approach with GCP, but that did not work