Create and deploy an HTTP Cloud Run function by using Java (1st gen)
This guide takes you through the process of writing a Cloud Run function using the Java runtime. There are two types of Cloud Run 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 Pub/Sub topic, or changes in a Cloud Storage bucket.
The document shows how to create a simple HTTP function and build it using either Maven or Gradle.
Before you begin
- 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.
-
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.
-
Enable the Cloud Functions and Cloud Build APIs.
- Install and initialize the Google Cloud SDK.
- Update and install
gcloud
components:gcloud components update
- Prepare your development environment.
Create a function
This section describes how to create a function.
Maven
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 the project structure to contain the source directory and source file.
mkdir -p src/main/java/functions touch src/main/java/functions/HelloWorld.java
Add the following contents to the
HelloWorld.java
file:This example function outputs the greeting "Hello World!"
Gradle
Create a directory on your local system for the function code:
Linux or Mac OS X:
mkdir ~/helloworld-gradle cd ~/helloworld-gradle
Windows:
mkdir %HOMEPATH%\helloworld-gradle cd %HOMEPATH%\helloworld-gradle
Create the project structure to contain the source directory and source file.
mkdir -p src/main/java/functions touch src/main/java/functions/HelloWorld.java
Add the following contents to the
HelloWorld.java
file:This example function outputs the greeting "Hello World!"
Specify dependencies
The next step is to set up dependencies:
Maven
Change directory to the helloworld
directory you created above, and create
a pom.xml
file:
cd ~/helloworld
touch pom.xml
To manage dependencies using Maven, specify the dependencies in
the <dependencies>
section inside the pom.xml file
of your project. For this exercise, copy the following contents
into your pom.xml
file.
See helloworld for a complete sample based on Maven.
Gradle
Change directory to the helloworld-gradle
directory you created above, and
create a build.gradle
file:
cd ~/helloworld-gradle
touch build.gradle
To manage dependencies using Gradle, specify the dependencies in
the build.gradle file
of your project. For this exercise, copy the following contents
into your build.gradle
file. Note that this build.gradle
file includes a
custom task to help you run functions locally.
See helloworld-gradle for a complete sample based on Gradle.
Build and test locally
Before deploying the function, you can build and test it locally:
Maven
Run the following command to confirm that your function builds:
mvn compile
Another option is to use the mvn package
command to compile your Java
code, run any tests, and package the code up in a JAR file within the target
directory. You can learn more about the Maven build lifecycle
here.
To test the function, run the following command:
mvn function:run
Gradle
Run the following command to confirm that your function builds:
gradle build
To test the function, run the following command:
gradle runFunction -Prun.functionTarget=functions.HelloWorld
If testing completes successfully, it displays the URL you can visit in your web
browser to see the function in action:
http://localhost:8080/
. You should see a Hello World!
message.
Alternatively, you can send requests to this function using curl
from another
terminal window:
curl localhost:8080
# Output: Hello World!
Deploy the function
Maven
To deploy the function with an HTTP trigger, run the following
command in the helloworld
directory:
gcloud functions deploy my-first-function --no-gen2 --entry-point functions.HelloWorld --runtime java17 --trigger-http --memory 512MB --allow-unauthenticated
where my-first-function
is the registered name by which your function
will be identified in the Google Cloud console, and --entry-point
specifies
your function's fully qualified class name (FQN).
Gradle
To deploy the function with an HTTP trigger, run the following
command in the helloworld-gradle
directory:
gcloud functions deploy my-first-function --no-gen2 --entry-point functions.HelloWorld --runtime java17 --trigger-http --memory 512MB --allow-unauthenticated
where my-first-function
is the registered name by which your function
will be identified in the Google Cloud console, and --entry-point
specifies
your function's fully qualified class name (FQN).
Test the deployed function
When the function finishes deploying, take note of the
httpsTrigger.url
property or find it using the following command:gcloud functions describe my-first-function
It should look like this:
https://GCP_REGION-PROJECT_ID.cloudfunctions.net/my-first-function
Visit this URL in your browser. You should see a
Hello World!
message.
View logs
Logs for Cloud Run functions are viewable using the Google Cloud CLI, and in the Cloud Logging UI.
Use the command-line tool
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 my-first-function
The output should resemble the following:
LEVEL NAME EXECUTION_ID TIME_UTC LOG D my-first-function k2bqgroszo4u 2020-07-24 18:18:01.791 Function execution started D my-first-function k2bqgroszo4u 2020-07-24 18:18:01.958 Function execution took 168 ms, finished with status code: 200 ...
Use the Logging dashboard
You can also view logs for Cloud Run functions from the Google Cloud console.