GCP - Create api with Cloud Functions and API Gateway

Introduction

In this article, we will explore how to create an API using Google Cloud Platform (GCP) Cloud Functions and API Gateway. Cloud Functions allow you to build serverless applications that can scale automatically based on demand. API Gateway is a service that acts as a central point of entry for your API requests, allowing you to handle tasks such as routing, authentication, rate limiting, and more.

By combining these two services, you can create a highly scalable and flexible API that can handle a wide range of use cases.

Prerequisites

Before we get started, make sure you have the following:

• A GCP working account

Tasks:

There are total3 tasks for this activity
Task 1 - service account creation
Task 2 - cloud function creation
Task 3 - api gateway creation

Task-1: Create 2 Service Account

Let's create two service accounts.

1. For Cloud function - backend-function
2. For api-gateway - api-gateway

• Go to iam -> Service Accounts -> +CREATE SERVICE ACCOUNT

• copy the email generated for api-gateway service account

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Task-2: Create Cloud function

• Go to - Cloud Functions -> +CREATE FUNCTION

• choose backend-function service account

• Leave all other function details to default -

• Now, Deploy the function
• After this, a function will be deployed

Change the permission for cloud function

• add principal
  

• give the permission to api-gateway account for function invocation.

• Save it and policy will be updated and it will look like below image

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Task-3: Create Api-Gateway

• Get the address from cloud function from trigger section

• make api-spec file and change the address value which is found in above step

swagger: '2.0'
info:
  title: test-name-spec
  description: Sample API on API Gateway with a Google Cloud Functions backend
  version: 1.0.0
schemes:
  - https
produces:
  - application/json
paths:
  /hello:
    get:
      summary: Greet a user
      operationId: hello
      x-google-backend:
        address: https://us-central1-qwiklabs-gcp-03-3b06fe0404f2.cloudfunctions.net/cloud-backend-function
      responses:
        '200':
          description: A successful response
          schema:
            type: string

• Create the gateway with above file and add the details similar to given screenshot

• Wait for the API Gateway to be created, it will look like this after completion

• Go to newly created api-gateway and get the URL for api gateway from gateways tab

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• add hello after the given url and we will be able to access the api like this