HTTP Tutorial

This simple tutorial demonstrates writing, deploying, and triggering an HTTP Cloud Function.

Objectives

Costs

This tutorial uses billable components of Cloud Platform, including:

  • Google Cloud Functions

Use the Pricing Calculator to generate a cost estimate based on your projected usage.

Before you begin

  1. Sign in to your Google Account.

    If you don't already have one, sign up for a new account.

  2. In the Google Cloud Console, on the project selector page, select or create a Google Cloud project.

    Go to the project selector page

  3. Make sure that billing is enabled for your Cloud project. Learn how to confirm that billing is enabled for your project.

  4. Enable the Cloud Functions and Cloud Build APIs.

    Enable the APIs

  5. Install and initialize the Cloud SDK.
  6. If you already have the Cloud SDK installed, update it by running the following command:

    gcloud components update
  7. Prepare your development environment.

Preparing the application

  1. Clone the sample app repository to your local machine:

    Node.js

    git clone https://github.com/GoogleCloudPlatform/nodejs-docs-samples.git

    Alternatively, you can download the sample as a zip file and extract it.

    Python

    git clone https://github.com/GoogleCloudPlatform/python-docs-samples.git

    Alternatively, you can download the sample as a zip file and extract it.

    Go

    git clone https://github.com/GoogleCloudPlatform/golang-samples.git

    Alternatively, you can download the sample as a zip file and extract it.

    Java

    git clone https://github.com/GoogleCloudPlatform/java-docs-samples.git

    Alternatively, you can download the sample as a zip file and extract it.

    C#

    git clone https://github.com/GoogleCloudPlatform/dotnet-docs-samples.git

    Alternatively, you can download the sample as a zip file and extract it.

    Ruby

    git clone https://github.com/GoogleCloudPlatform/ruby-docs-samples.git

    Alternatively, you can download the sample as a zip file and extract it.

  2. Change to the directory that contains the Cloud Functions sample code:

    Node.js

    cd nodejs-docs-samples/functions/helloworld/

    Python

    cd python-docs-samples/functions/helloworld/

    Go

    cd golang-samples/functions/helloworld/

    Java

    cd java-docs-samples/functions/helloworld/helloworld/

    C#

    cd dotnet-docs-samples/functions/helloworld/HelloWorld/

    Ruby

    cd ruby-docs-samples/functions/helloworld/

  3. Take a look at the sample code:

    Node.js

    /**
     * HTTP Cloud Function.
     * This function is exported by index.js, and is executed when
     * you make an HTTP request to the deployed function's endpoint.
     *
     * @param {Object} req Cloud Function request context.
     *                     More info: https://expressjs.com/en/api.html#req
     * @param {Object} res Cloud Function response context.
     *                     More info: https://expressjs.com/en/api.html#res
     */
    exports.helloGET = (req, res) => {
      res.send('Hello World!');
    };

    Python

    def hello_get(request):
        """HTTP Cloud Function.
        Args:
            request (flask.Request): The request object.
            <https://flask.palletsprojects.com/en/1.1.x/api/#incoming-request-data>
        Returns:
            The response text, or any set of values that can be turned into a
            Response object using `make_response`
            <https://flask.palletsprojects.com/en/1.1.x/api/#flask.make_response>.
        Note:
            For more information on how Flask integrates with Cloud
            Functions, see the `Writing HTTP functions` page.
            <https://cloud.google.com/functions/docs/writing/http#http_frameworks>
        """
        return 'Hello World!'

    Go

    
    // Package helloworld provides a set of Cloud Functions samples.
    package helloworld
    
    import (
    	"fmt"
    	"net/http"
    )
    
    // HelloGet is an HTTP Cloud Function.
    func HelloGet(w http.ResponseWriter, r *http.Request) {
    	fmt.Fprint(w, "Hello, World!")
    }
    

    Java

    
    package functions;
    
    import com.google.cloud.functions.HttpFunction;
    import com.google.cloud.functions.HttpRequest;
    import com.google.cloud.functions.HttpResponse;
    import java.io.BufferedWriter;
    import java.io.IOException;
    
    public class HelloWorld implements HttpFunction {
      // Simple function to return "Hello World"
      @Override
      public void service(HttpRequest request, HttpResponse response)
          throws IOException {
        BufferedWriter writer = response.getWriter();
        writer.write("Hello World!");
      }
    }

    C#

    using Google.Cloud.Functions.Framework;
    using Microsoft.AspNetCore.Http;
    using System.Threading.Tasks;
    
    namespace HelloWorld
    {
        public class Function : IHttpFunction
        {
            public async Task HandleAsync(HttpContext context)
            {
                await context.Response.WriteAsync("Hello World!");
            }
        }
    }

    Ruby

    require "functions_framework"
    
    FunctionsFramework.http "hello_get" do |_request|
      # The request parameter is a Rack::Request object.
      # See https://www.rubydoc.info/gems/rack/Rack/Request
    
      # Return the response body as a string.
      # You can also return a Rack::Response object, a Rack response array, or
      # a hash which will be JSON-encoded into a response.
      "Hello World!"
    end

Deploying the function

To deploy the function with an HTTP trigger, run the following command in the directory that contains the sample code (or in the case of Java, the pom.xml file):

Node.js

gcloud functions deploy helloGET \
--runtime nodejs10 --trigger-http --allow-unauthenticated
You can use the following values for the --runtime flag to specify your preferred Node.js version:
  • nodejs10
  • nodejs12
  • nodejs14 (public preview)

Python

gcloud functions deploy hello_get \
--runtime python38 --trigger-http --allow-unauthenticated
You can use the following values for the --runtime flag to specify your preferred Python version:
  • python37
  • python38
  • python39 (public preview)

Go

gcloud functions deploy HelloGet \
--runtime go113 --trigger-http --allow-unauthenticated
You can use the following values for the --runtime flag to specify your preferred Go version:
  • go111 (Deprecated)
  • go113

Java

gcloud functions deploy java-http-function \
--entry-point functions.HelloWorld \
--runtime java11 \
--memory 512MB --trigger-http --allow-unauthenticated

C#

gcloud functions deploy csharp-http-function \
--entry-point HelloWorld.Function \
--runtime dotnet3 --trigger-http --allow-unauthenticated

Ruby

gcloud functions deploy hello_get --runtime ruby26 --trigger-http --allow-unauthenticated
You can use the following values for the --runtime flag to specify your preferred Ruby version:
  • ruby26
  • ruby27

The --allow-unauthenticated flag lets you reach the function without authentication. To require authentication, omit the flag.

Triggering the function

To make an HTTP request to your function, run the following command:

Node.js

curl "https://REGION-PROJECT_ID.cloudfunctions.net/helloGET" 

Python

curl "https://REGION-PROJECT_ID.cloudfunctions.net/hello_get" 

Go

curl "https://REGION-PROJECT_ID.cloudfunctions.net/HelloGet" 

Java

curl "https://REGION-PROJECT_ID.cloudfunctions.net/java-http-function" 

C#

curl "https://REGION-PROJECT_ID.cloudfunctions.net/csharp-http-function" 

Ruby

curl "https://REGION-PROJECT_ID.cloudfunctions.net/hello_get" 

where

  • REGION is the region where your function is deployed. This is visible in your terminal when your function finishes deploying.
  • PROJECT_ID is your Cloud project ID. This is visible in your terminal when your function finishes deploying.

You can also visit the deployed function's endpoint in your browser to see the "Hello World!" message.

Cleaning up

To avoid incurring charges to your Google Cloud account for the resources used in this tutorial, either delete the project that contains the resources, or keep the project and delete the individual resources.

Deleting the project

The easiest way to eliminate billing is to delete the project that you created for the tutorial.

To delete the project:

  1. In the Cloud Console, go to the Manage resources page.

    Go to Manage resources

  2. In the project list, select the project that you want to delete, and then click Delete.
  3. In the dialog, type the project ID, and then click Shut down to delete the project.

Deleting the Cloud Function

Deleting Cloud Functions does not remove any resources stored in Cloud Storage.

To delete the Cloud Function you created in this tutorial, run the following command:

Node.js

gcloud functions delete helloGET 

Python

gcloud functions delete hello_get 

Go

gcloud functions delete HelloGet 

Java

gcloud functions delete java-http-function 

C#

gcloud functions delete csharp-http-function 

Ruby

gcloud functions delete hello_get 

You can also delete Cloud Functions from the Google Cloud Console.