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Google Cloud Functions

What is Google Cloud Functions?​

GCF is a serverless execution environment for building and connecting cloud services. It allows you to run a webhook for your SignalWire application without having to host a web server, and it is a good alternative in case you need some simple logic that cannot be achieved just by using XML.

The example application sets up a webhook to handle a phone call. In this case we will check the day of the week, and return a different greeting depending on the day. This is simple logic, yet hard to accomplish using static cXML applications, and you might not want to set up a full web server just to host this snippet.

Setting up Google Cloud Functions​

Start with the Google Cloud Functions HTTP tutorial.

You will have to set up a few things:

  • The gcloud command-line tool
  • A Google Cloud account with billing enabled
  • Your first project
  • gcloud login

Configuring the Code​

The function we developed as a sample is pretty straightforward, and as you can see is plain Node Javascript, without anything specific to being deployed on Google Cloud Functions. Make sure to have NodeJS version 10 installed.

const { RestClient } = require('@signalwire/compatibility-api')

exports.helloLaml = (req, res) => {
  const response = new RestClient.LaML.VoiceResponse();
  try {
    var d = new Date();
    if (d.getDay() == 0) {
      response.say('Happy Sunday! Our store is closed today');
    } else {
      response.say('Hello! Our store is open from 9 to 6 today.');
    }
  } catch(err) {
    console.log(err.message);
  } finally {
    res.status(200)
      .set('Content-Type', 'text/xml')
      .send(response.toString());
  }
};

Deploying the Code to Google Cloud Functions​

After setting up the necessary prerequisites above, clone this repository and deploy your function using the command below:

cloud functions deploy hello-laml --trigger-http --runtime nodejs10 --entry-point=helloLaml --allow-unauthenticated

In the above, we deploy a function named hello-laml, specifying it should use the helloLaml method from the index.js file as entrypoint, and we allow requests to come in unauthenticated.

The GCF CLI output will contain an URL similar to https://us-central1-yourprojectname.cloudfunctions.net/hello-laml. That is the URL to use as your webhook in the SignalWire Dashboard.

Sign Up Here​

If you would like to test this example out, you can create a SignalWire account and Space here.

Please feel free to reach out to us on our Community Slack or create a Support ticket if you need guidance!