Get started: write, test, and deploy your first functions

Once your functions are working as desired in the emulator, you can proceed to deploying, testing, and running them in the production environment. Keep in mind that to deploy to the recommended Node.js 14 runtime environment, your project must be on the Blaze pricing plan. See Cloud Functions pricing.

To complete the tutorial, deploy your functions and then execute addMessage() to trigger makeUppercase().

1. Run this command to deploy your functions:

    firebase deploy --only functions
    

   After you run this command, the Firebase CLI outputs the URL for any HTTP function endpoints. In your terminal, you should see a line like the following:

   Function URL (addMessage): https://us-central1-MY_PROJECT.cloudfunctions.net/addMessage
   

   The URL contains your project ID as well as a region for the HTTP function. Though you don't need to worry about it now, some production HTTP functions should specify a location to minimize network latency.

   If you encounter access errors such as "Unable to authorize access to project," try checking your project aliasing.

2. Using the addMessage() URL output by the CLI, add a text query parameter, and open it in a browser:

   https://us-central1-MY_PROJECT.cloudfunctions.net/addMessage?text=uppercasemetoo
   

   The function executes and redirects the browser to the Firebase console at the database location where the text string is stored. This write event triggers makeUppercase(), which writes an uppercase version of the string.

After deploying and executing functions, you can view logs in the Google Cloud console. If you need to delete functions in development or production, use the Firebase CLI.

In production, you may want to optimize function performance and control costs by setting minimum and maximum numbers of instances to run. See Control scaling behavior for more information on these runtime options.

Review complete sample code

Here's the completed functions/index.js containing the functions addMessage() and makeUppercase(). These functions allow you to pass a parameter to an HTTP endpoint that writes a value to Cloud Firestore, and then transforms it by uppercasing all characters in the string.

// The Cloud Functions for Firebase SDK to create Cloud Functions and set up triggers.
const functions = require('firebase-functions/v1');

// The Firebase Admin SDK to access Firestore.
const admin = require("firebase-admin");
admin.initializeApp();

// Take the text parameter passed to this HTTP endpoint and insert it into
// Firestore under the path /messages/:documentId/original
exports.addMessage = functions.https.onRequest(async (req, res) => {
  // Grab the text parameter.
  const original = req.query.text;
  // Push the new message into Firestore using the Firebase Admin SDK.
  const writeResult = await admin
    .firestore()
    .collection("messages")
    .add({ original: original });
  // Send back a message that we've successfully written the message
  res.json({ result: `Message with ID: ${writeResult.id} added.` });
});

// Listens for new messages added to /messages/:documentId/original and creates an
// uppercase version of the message to /messages/:documentId/uppercase
exports.makeUppercase = functions.firestore
  .document("/messages/{documentId}")
  .onCreate((snap, context) => {
    // Grab the current value of what was written to Firestore.
    const original = snap.data().original;

    // Access the parameter `{documentId}` with `context.params`
    functions.logger.log("Uppercasing", context.params.documentId, original);

    const uppercase = original.toUpperCase();

    // You must return a Promise when performing asynchronous tasks inside a Functions such as
    // writing to Firestore.
    // Setting an 'uppercase' field in Firestore document returns a Promise.
    return snap.ref.set({ uppercase }, { merge: true });
  });
index.js

Next steps

In this documentation, you can learn more about how to manage functions for Cloud Functions as well as how to to handle all event types supported by Cloud Functions.

To learn more about Cloud Functions, you could also do the following:

• Read about use cases for Cloud Functions.
• Try the Cloud Functions codelab.
• Review and run code samples on GitHub