Create and deploy a HTTP Cloud Function by using Go
This guide takes you through the process of writing a Cloud Function using the Go runtime. There are two types of Cloud Functions:
- An HTTP function, which you invoke from standard HTTP requests.
- An event-driven function, which you use to handle events from your Cloud infrastructure, such as messages on a Cloud Pub/Sub topic, or changes in a Cloud Storage bucket.
The sample shows how to create a simple HTTP function.
Guide structure
- Creating a GCP project using gcloud CLI
- Creating a function
- Specifying dependencies
- Deploying your function
- Testing your function
Creating a GCP project using gcloud CLI
- Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.
-
In the Google Cloud console, on the project selector page, select or create a Google Cloud project.
-
Make sure that billing is enabled for your Google Cloud project. Learn how to check if billing is enabled on a project.
-
Enable the Cloud Functions and Cloud Build APIs.
-
In the Google Cloud console, on the project selector page, select or create a Google Cloud project.
-
Make sure that billing is enabled for your Google Cloud project. Learn how to check if billing is enabled on a project.
-
Enable the Cloud Functions and Cloud Build APIs.
- Install and initialize the gcloud CLI.
- Update and install
gcloud
components:gcloud components update
- Prepare your development environment.
Creating a function
Create a directory on your local system for the function code:
Linux or Mac OS X
mkdir ~/helloworld cd ~/helloworld
Windows
mkdir %HOMEPATH%\helloworld cd %HOMEPATH%\helloworld
Create a file called
hello_http.go
in thehelloworld
directory with the following contents:This example function takes a name supplied in the HTTP request and returns a greeting, or "Hello, World!" when no name is supplied.
Specifying dependencies
This example function only uses Go standard library packages, so you don't need to declare any dependencies beyond just importing the packages.
For functions that require dependencies outside of the standard library,
you must provide the dependencies via either a go.mod
file or a vendor
directory. For more details, read
Specifying dependencies in Go.
Deploying the function
To deploy the function with an HTTP trigger, run the following
command in the helloworld
directory, specifying either go113
or
go111
as the value for the --runtime
flag, depending on which version you
are using:
gcloud functions deploy HelloHTTP --runtime go120 --trigger-http --allow-unauthenticated
The --allow-unauthenticated
flag lets you reach the function
without authentication.
To require
authentication, omit the
flag.
Testing the function
When the function finishes deploying, take note of the
httpsTrigger.url
property or find it using the following command:gcloud functions describe HelloHTTP
It should look like this:
https://GCP_REGION-PROJECT_ID.cloudfunctions.net/HelloHTTP
Visit this URL in your browser, or use cURL by running the command:
curl https://GCP_REGION-PROJECT_ID.cloudfunctions.net/HelloHTTP
You should see a "Hello, World!" message. Try passing a name in the HTTP request by running the following command:
curl -X POST https://GCP_REGION-PROJECT_ID.cloudfunctions.net/HelloHTTP -H "Content-Type:application/json" -d '{"name":"NAME"}'
You should see the message "Hello,
NAME
!"
Viewing logs
Using the command-line tool
Logs for Cloud Functions are viewable in the Cloud Logging UI, and via the Google Cloud CLI.
To view logs for your function with the gcloud CLI, use the
logs read
command, followed by
the name of the function:
gcloud functions logs read HelloHTTP
The output should resemble the following:
LEVEL NAME EXECUTION_ID TIME_UTC LOG D HelloHTTP buv9ej2k1a7r 2019-09-20 13:23:18.910 Function execution started D HelloHTTP buv9ej2k1a7r 2019-09-20 13:23:18.913 Function execution took 4 ms, finished with status code: 200
Using the Logging dashboard
You can also view logs for Cloud Functions from the Google Cloud console.