Google Cloud Functions

Google Cloud Functions is a serverless execution environment for building and connecting cloud services. With Cloud Functions you write simple, single-purpose functions that are attached to events emitted from your cloud infrastructure and services. Your function is triggered when an event being watched is fired. Your code executes in a fully managed environment. There is no need to provision any infrastructure or worry about managing any servers.

Listen and respond to a file upload to Cloud Storage, a log change, or an incoming message on a Pub/Sub topic. Cloud Functions augments existing cloud services and allows you to address an increasing number of use cases with arbitrary programming logic.

Cloud events are things that happen in your cloud environment. These might be things like changes to data in a database, files added to a storage system, or a new virtual machine instance being created.

Events occur whether or not you choose to respond to them. You create a response to an event with a trigger. A trigger is a declaration that you are interested in a certain event or set of events. Binding a function to a trigger allows you to capture and act on events.

Enable the Cloud Functions, Cloud Build, Artifact Registry, Cloud Run, and Logging APIs.

post configuration add the function code which needs to be triggered mine will be in 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!");
  }
}

Deploy a function

deploying via gcloud

To deploy the function with an HTTP trigger, run the following command in the directory that contains the sample code

gcloud functions deploy java-http-function \
--gen2 \
--runtime=java17 \
--region=REGION \
--source=. \
--entry-point=functions.HelloWorld \
--memory=512MB \
--trigger-http \
--allow-unauthenticated