If you are creating a new function, see the Console Quickstart on Cloud Run. The content on this page only applies to existing legacy functions created with the Cloud Functions v1 API.

JVM Languages

It's possible to write your function in using different JVM languages (such as Kotlin , Groovy , or Scala ) as long as they conform to the following rules:

The function is a public class that implements one of the function interfaces ( HttpFunction , BackgroundFunction , or RawBackgroundFunction ) and has a public no-argument constructor.
If you are deploying from source:
- It can be built from Maven.
- The build file contains all the plugins to produce compiled classes.
If you are deploying from a pre-built JAR:
- You can use any build tools to produce this JAR.
- The pre-built JAR must be a Fat JAR with all of its dependency classes, or its manifest must contain a Class-Path entry with the relative locations of jars containing those dependency classes.

HTTP function examples

You use HTTP functions when you want to invoke your function via an HTTP(S) request. The following examples output the message "Hello World!"

Kotlin

  import 
  
 com.google.cloud.functions.HttpFunction 
 import 
  
 com.google.cloud.functions.HttpRequest 
 import 
  
 com.google.cloud.functions.HttpResponse 
 import 
  
 java.io.IOException 
 import 
  
 java.util.logging.Logger 
 class 
  
 HelloWorld 
  
 : 
  
 HttpFunction 
  
 { 
  
 // Simple function to return "Hello World" 
  
 @Throws 
 ( 
 IOException 
 :: 
 class 
 ) 
  
 override 
  
 fun 
  
 service 
 ( 
 request 
 : 
  
 HttpRequest 
 , 
  
 response 
 : 
  
 HttpResponse 
 ) 
  
 { 
  
 response 
 . 
 writer 
 . 
 write 
 ( 
 "Hello World!" 
 ) 
  
 } 
 }

Groovy

  import 
  
 com.google.cloud.functions.HttpFunction 
 import 
  
 com.google.cloud.functions.HttpRequest 
 import 
  
 com.google.cloud.functions.HttpResponse 
 class 
  
 GroovyHelloWorld 
  
 implements 
  
 HttpFunction 
  
 { 
  
 @Override 
  
 void 
  
 service 
 ( 
 HttpRequest 
  
 request 
 , 
  
 HttpResponse 
  
 response 
 ) 
  
 { 
  
 response 
 . 
 writer 
 . 
 write 
 ( 
 "Hello World!" 
 ) 
  
 } 
 }

Scala

  class 
  
 ScalaHelloWorld 
  
 extends 
  
 HttpFunction 
  
 { 
  
 override 
  
 def 
  
 service 
 ( 
 httpRequest 
 : 
  
 HttpRequest 
 , 
  
 httpResponse 
 : 
  
 HttpResponse 
 ): 
  
 Unit 
  
 = 
  
 { 
  
 httpResponse 
 . 
 getWriter 
 . 
 write 
 ( 
 "Hello World!" 
 ) 
  
 } 
 }

`pom.xml` file for HTTP examples

Here are the pom.xml files for the above samples:

Kotlin

 < project 
  
 xmlns 
 = 
 "http://maven.apache.org/POM/4.0.0" 
  
 xmlns 
 : 
 xsi 
 = 
 "http://www.w3.org/2001/XMLSchema-instance" 
  
 xsi 
 : 
 schemaLocation 
 = 
 "http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" 
>  
< modelVersion>4 
 .0.0 
< / 
 modelVersion 
>  
< groupId>com 
 . 
 example 
 . 
 functions 
< / 
 groupId 
>  
< artifactId>functions 
 - 
 kotlin 
 - 
 hello 
 - 
 world 
< / 
 artifactId 
>  
< properties 
>  
< maven 
 . 
 compiler 
 . 
 target>11 
< / 
 maven 
 . 
 compiler 
 . 
 target 
>  
< maven 
 . 
 compiler 
 . 
 source>11 
< / 
 maven 
 . 
 compiler 
 . 
 source 
>  
< project 
 . 
 build 
 . 
 sourceEncoding>UTF 
 - 
 8 
< / 
 project 
 . 
 build 
 . 
 sourceEncoding 
>  
< kotlin 
 . 
 version>1 
 .9.22 
< / 
 kotlin 
 . 
 version 
>  
< / 
 properties 
>  
< dependencies 
>  
< !-- 
  
 Required 
  
 for 
  
 Function 
  
 primitives 
  
 -- 
>  
< dependency 
>  
< groupId>com 
 . 
 google 
 . 
 cloud 
 . 
 functions 
< / 
 groupId 
>  
< artifactId>functions 
 - 
 framework 
 - 
 api 
< / 
 artifactId 
>  
< version>1 
 .1.0 
< / 
 version 
>  
< scope>provided 
< / 
 scope 
>  
< / 
 dependency 
>  
< dependency 
>  
< groupId>org 
 . 
 jetbrains 
 . 
 kotlin 
< / 
 groupId 
>  
< artifactId>kotlin 
 - 
 stdlib 
 - 
 jdk8 
< / 
 artifactId 
>  
< version>$ 
 { 
 kotlin 
 . 
 version 
 } 
< / 
 version 
>  
< / 
 dependency 
>  
< dependency 
>  
< groupId>org 
 . 
 jetbrains 
 . 
 kotlin 
< / 
 groupId 
>  
< artifactId>kotlin 
 - 
 test 
< / 
 artifactId 
>  
< version>$ 
 { 
 kotlin 
 . 
 version 
 } 
< / 
 version 
>  
< scope>test 
< / 
 scope 
>  
< / 
 dependency 
>  
< / 
 dependencies 
>  
< build 
>  
< plugins 
>  
< plugin 
>  
< !-- 
  
 Google 
  
 Cloud 
  
 Functions 
  
 Framework 
  
 Maven 
  
 plugin 
  
 This 
  
 plugin 
  
 allows 
  
 you 
  
 to 
  
 run 
  
 Cloud 
  
 Functions 
  
 Java 
  
 code 
  
 locally 
 . 
  
 Use 
  
 the 
  
 following 
  
 terminal 
  
 command 
  
 to 
  
 run 
  
 a 
  
 given 
  
 function 
  
 locally 
 : 
  
 mvn 
  
 function 
 : 
 run 
  
 - 
 Drun 
 . 
 functionTarget 
 = 
 your 
 . 
 package 
 . 
 yourFunction 
  
 -- 
>  
< groupId>com 
 . 
 google 
 . 
 cloud 
 . 
 functions 
< / 
 groupId 
>  
< artifactId>function 
 - 
 maven 
 - 
 plugin 
< / 
 artifactId 
>  
< version>0 
 .11.0 
< / 
 version 
>  
< configuration 
>  
< functionTarget>functions 
 . 
 HelloWorld 
< / 
 functionTarget 
>  
< / 
 configuration 
>  
< / 
 plugin 
>  
< plugin 
>  
< groupId>org 
 . 
 jetbrains 
 . 
 kotlin 
< / 
 groupId 
>  
< artifactId>kotlin 
 - 
 maven 
 - 
 plugin 
< / 
 artifactId 
>  
< version>$ 
 { 
 kotlin 
 . 
 version 
 } 
< / 
 version 
>  
< executions 
>  
< execution 
>  
< id>compile 
< / 
 id 
>  
< phase>compile 
< / 
 phase 
>  
< goals 
>  
< goal>compile 
< / 
 goal 
>  
< / 
 goals 
>  
< configuration 
>  
< sourceDirs 
>  
< source>src 
 / 
 main 
 / 
 kotlin 
< / 
 source 
>  
< / 
 sourceDirs 
>  
< / 
 configuration 
>  
< / 
 execution 
>  
< execution 
>  
< id>test 
 - 
 compile 
< / 
 id 
>  
< phase>test 
 - 
 compile 
< / 
 phase 
>  
< goals 
>  
< goal>test 
 - 
 compile 
< / 
 goal 
>  
< / 
 goals 
>  
< / 
 execution 
>  
< / 
 executions 
>  
< configuration 
>  
< jvmTarget>1 
 .8 
< / 
 jvmTarget 
>  
< / 
 configuration 
>  
< / 
 plugin 
>  
< / 
 plugins 
>  
< / 
 build 
>
< / 
 project 
>

Groovy

 < project 
  
 xmlns 
 = 
 "http://maven.apache.org/POM/4.0.0" 
  
 xmlns 
 : 
 xsi 
 = 
 "http://www.w3.org/2001/XMLSchema-instance" 
  
 xsi 
 : 
 schemaLocation 
 = 
 "http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" 
>  
< modelVersion>4 
 .0.0 
< / 
 modelVersion 
>  
< groupId>com 
 . 
 example 
 . 
 functions 
< / 
 groupId 
>  
< artifactId>functions 
 - 
 groovy 
 - 
 hello 
 - 
 world 
< / 
 artifactId 
>  
< properties 
>  
< maven 
 . 
 compiler 
 . 
 target>11 
< / 
 maven 
 . 
 compiler 
 . 
 target 
>  
< maven 
 . 
 compiler 
 . 
 source>11 
< / 
 maven 
 . 
 compiler 
 . 
 source 
>  
< project 
 . 
 build 
 . 
 sourceEncoding>UTF 
 - 
 8 
< / 
 project 
 . 
 build 
 . 
 sourceEncoding 
>  
< groovy 
 . 
 version>3 
 .0.20 
< / 
 groovy 
 . 
 version 
>  
< / 
 properties 
>  
< dependencyManagement 
>  
< dependencies 
>  
< dependency 
>  
< artifactId>libraries 
 - 
 bom 
< / 
 artifactId 
>  
< groupId>com 
 . 
 google 
 . 
 cloud 
< / 
 groupId 
>  
< scope>import 
< / 
 scope 
>  
< type>pom 
< / 
 type 
>  
< version>26 
 .32.0 
< / 
 version 
>  
< / 
 dependency 
>  
< / 
 dependencies 
>  
< / 
 dependencyManagement 
>  
< dependencies 
>  
< !-- 
  
 Required 
  
 for 
  
 Function 
  
 primitives 
  
 -- 
>  
< dependency 
>  
< groupId>com 
 . 
 google 
 . 
 cloud 
 . 
 functions 
< / 
 groupId 
>  
< artifactId>functions 
 - 
 framework 
 - 
 api 
< / 
 artifactId 
>  
< version>1 
 .1.0 
< / 
 version 
>  
< scope>provided 
< / 
 scope 
>  
< / 
 dependency 
>  
< !-- 
  
 Required 
  
 for 
  
 groovy 
  
 samples 
  
 -- 
>  
< dependency 
>  
< groupId>org 
 . 
 codehaus 
 . 
 groovy 
< / 
 groupId 
>  
< artifactId>groovy 
 - 
 all 
< / 
 artifactId 
>  
< version>$ 
 { 
 groovy 
 . 
 version 
 } 
< / 
 version 
>  
< type>pom 
< / 
 type 
>  
< / 
 dependency 
>  
< / 
 dependencies 
>  
< build 
>  
< plugins 
>  
< plugin 
>  
< !-- 
  
 Google 
  
 Cloud 
  
 Functions 
  
 Framework 
  
 Maven 
  
 plugin 
  
 This 
  
 plugin 
  
 allows 
  
 you 
  
 to 
  
 run 
  
 Cloud 
  
 Functions 
  
 Java 
  
 code 
  
 locally 
 . 
  
 Use 
  
 the 
  
 following 
  
 terminal 
  
 command 
  
 to 
  
 run 
  
 a 
  
 given 
  
 function 
  
 locally 
 : 
  
 mvn 
  
 function 
 : 
 run 
  
 - 
 Drun 
 . 
 functionTarget 
 = 
 your 
 . 
 package 
 . 
 yourFunction 
  
 -- 
>  
< groupId>com 
 . 
 google 
 . 
 cloud 
 . 
 functions 
< / 
 groupId 
>  
< artifactId>function 
 - 
 maven 
 - 
 plugin 
< / 
 artifactId 
>  
< version>0 
 .11.0 
< / 
 version 
>  
< configuration 
>  
< functionTarget>functions 
 . 
 GroovyHelloWorld 
< / 
 functionTarget 
>  
< / 
 configuration 
>  
< / 
 plugin 
>  
< plugin 
>  
< groupId>org 
 . 
 codehaus 
 . 
 gmavenplus 
< / 
 groupId 
>  
< artifactId>gmavenplus 
 - 
 plugin 
< / 
 artifactId 
>  
< version>3 
 .0.2 
< / 
 version 
>  
< executions 
>  
< execution 
>  
< id>groovy 
 - 
 compile 
< / 
 id 
>  
< phase>process 
 - 
 resources 
< / 
 phase 
>  
< goals 
>  
< goal>addSources 
< / 
 goal 
>  
< goal>compile 
< / 
 goal 
>  
< / 
 goals 
>  
< / 
 execution 
>  
< / 
 executions 
>  
< dependencies 
>  
< dependency 
>  
< groupId>org 
 . 
 codehaus 
 . 
 groovy 
< / 
 groupId 
>  
< artifactId>groovy 
 - 
 all 
< / 
 artifactId 
>  
< !-- 
  
 any 
  
 version 
  
 of 
  
 Groovy 
  
 \ 
> = 
  
 1.5.0 
  
 should 
  
 work 
  
 here 
  
 -- 
>  
< version>$ 
 { 
 groovy 
 . 
 version 
 } 
< / 
 version 
>  
< scope>runtime 
< / 
 scope 
>  
< type>pom 
< / 
 type 
>  
< / 
 dependency 
>  
< / 
 dependencies 
>  
< / 
 plugin 
>  
< / 
 plugins 
>  
< / 
 build 
>
< / 
 project 
>

Scala

 < project 
  
 xmlns 
 = 
 "http://maven.apache.org/POM/4.0.0" 
  
 xmlns 
 : 
 xsi 
 = 
 "http://www.w3.org/2001/XMLSchema-instance" 
  
 xsi 
 : 
 schemaLocation 
 = 
 "http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" 
>  
< modelVersion>4 
 .0.0 
< / 
 modelVersion 
>  
< groupId>com 
 . 
 example 
 . 
 functions 
< / 
 groupId 
>  
< artifactId>functions 
 - 
 scala 
 - 
 hello 
 - 
 world 
< / 
 artifactId 
>  
< properties 
>  
< maven 
 . 
 compiler 
 . 
 target>11 
< / 
 maven 
 . 
 compiler 
 . 
 target 
>  
< maven 
 . 
 compiler 
 . 
 source>11 
< / 
 maven 
 . 
 compiler 
 . 
 source 
>  
< project 
 . 
 build 
 . 
 sourceEncoding>UTF 
 - 
 8 
< / 
 project 
 . 
 build 
 . 
 sourceEncoding 
>  
< / 
 properties 
>  
< dependencyManagement 
>  
< dependencies 
>  
< dependency 
>  
< artifactId>libraries 
 - 
 bom 
< / 
 artifactId 
>  
< groupId>com 
 . 
 google 
 . 
 cloud 
< / 
 groupId 
>  
< scope>import 
< / 
 scope 
>  
< type>pom 
< / 
 type 
>  
< version>26 
 .32.0 
< / 
 version 
>  
< / 
 dependency 
>  
< / 
 dependencies 
>  
< / 
 dependencyManagement 
>  
< dependencies 
>  
< !-- 
  
 Required 
  
 for 
  
 scala 
  
 samples 
  
 -- 
>  
< dependency 
>  
< groupId>org 
 . 
 scala 
 - 
 lang 
< / 
 groupId 
>  
< artifactId>scala 
 - 
 library 
< / 
 artifactId 
>  
< version>2 
 .13.5 
< / 
 version 
>  
< / 
 dependency 
>  
< !-- 
  
 Required 
  
 for 
  
 Function 
  
 primitives 
  
 -- 
>  
< dependency 
>  
< groupId>com 
 . 
 google 
 . 
 cloud 
 . 
 functions 
< / 
 groupId 
>  
< artifactId>functions 
 - 
 framework 
 - 
 api 
< / 
 artifactId 
>  
< version>1 
 .1.0 
< / 
 version 
>  
< scope>provided 
< / 
 scope 
>  
< / 
 dependency 
>  
< / 
 dependencies 
>  
< build 
>  
< plugins 
>  
< plugin 
>  
< !-- 
  
 Google 
  
 Cloud 
  
 Functions 
  
 Framework 
  
 Maven 
  
 plugin 
  
 This 
  
 plugin 
  
 allows 
  
 you 
  
 to 
  
 run 
  
 Cloud 
  
 Functions 
  
 Java 
  
 code 
  
 locally 
 . 
  
 Use 
  
 the 
  
 following 
  
 terminal 
  
 command 
  
 to 
  
 run 
  
 a 
  
 given 
  
 function 
  
 locally 
 : 
  
 mvn 
  
 function 
 : 
 run 
  
 - 
 Drun 
 . 
 functionTarget 
 = 
 your 
 . 
 package 
 . 
 yourFunction 
  
 -- 
>  
< groupId>com 
 . 
 google 
 . 
 cloud 
 . 
 functions 
< / 
 groupId 
>  
< artifactId>function 
 - 
 maven 
 - 
 plugin 
< / 
 artifactId 
>  
< version>0 
 .11.0 
< / 
 version 
>  
< configuration 
>  
< functionTarget>functions 
 . 
 ScalaHelloWorld 
< / 
 functionTarget 
>  
< / 
 configuration 
>  
< / 
 plugin 
>  
< plugin 
>  
< groupId>net 
 . 
 alchim31 
 . 
 maven 
< / 
 groupId 
>  
< artifactId>scala 
 - 
 maven 
 - 
 plugin 
< / 
 artifactId 
>  
< version>4 
 .4.1 
< / 
 version 
>  
< executions 
>  
< execution 
>  
< id>scala 
 - 
 compile 
< / 
 id 
>  
< phase>process 
 - 
 resources 
< / 
 phase 
>  
< goals 
>  
< goal>add 
 - 
 source 
< / 
 goal 
>  
< goal>compile 
< / 
 goal 
>  
< / 
 goals 
>  
< / 
 execution 
>  
< / 
 executions 
>  
< / 
 plugin 
>  
< / 
 plugins 
>  
< / 
 build 
>
< / 
 project 
>

Deploying the HTTP functions

Kotlin

  gcloud 
  
 functions 
  
 deploy 
  
 kotlin 
 - 
 helloworld 
  
 -- 
 entry 
 - 
 point 
  
 functions 
 . 
 KotlinHelloWorld 
  
 -- 
 no 
 - 
 gen2 
  
 -- 
 runtime 
  
 java17 
  
 -- 
 trigger 
 - 
 http 
  
 -- 
 allow 
 - 
 unauthenticated 
  
 -- 
 memory 
  
 512 
 MB

Groovy

  gcloud 
  
 functions 
  
 deploy 
  
 groovy 
 - 
 helloworld 
  
 -- 
 entry 
 - 
 point 
  
 functions 
 . 
 GroovyHelloWorld 
  
 -- 
 no 
 - 
 gen2 
  
 -- 
 runtime 
  
 java17 
  
 -- 
 trigger 
 - 
 http 
  
 -- 
 allow 
 - 
 unauthenticated 
  
 -- 
 memory 
  
 512 
 MB

Scala

  gcloud 
  
 functions 
  
 deploy 
  
 scala 
 - 
 helloworld 
  
 -- 
 entry 
 - 
 point 
  
 functions 
 . 
 ScalaHelloWorld 
  
 -- 
 no 
 - 
 gen2 
  
 -- 
 runtime 
  
 java17 
  
 -- 
 trigger 
 - 
 http 
  
 -- 
 allow 
 - 
 unauthenticated 
  
 -- 
 memory 
  
 512 
 MB

Event-driven function examples

You use event-driven functions when you want to have your Cloud Run function invoked indirectly in response to an asynchronous event, such as a message on a Pub/Sub topic, a change in a Cloud Storage bucket, or a Firebase event.

There are two types of event-driven functions : background functions and CloudEvent functions. The JVM languages only support background functions .

Kotlin

  import 
  
 com.google.cloud.functions.BackgroundFunction 
 import 
  
 com.google.cloud.functions.Context 
 import 
  
 functions.eventpojos.PubsubMessage 
 import 
  
 java.nio.charset.StandardCharsets 
 import 
  
 java.util.Base64 
 import 
  
 java.util.logging.Logger 
 class 
  
 KotlinHelloPubSub 
  
 : 
  
 BackgroundFunction<PubsubMessage> 
  
 { 
  
 override 
  
 fun 
  
 accept 
 ( 
 message 
 : 
  
 PubsubMessage 
 , 
  
 context 
 : 
  
 Context 
 ) 
  
 { 
  
 // name's default value is "world" 
  
 var 
  
 name 
  
 = 
  
 "world" 
  
 if 
  
 ( 
 message 
 ?. 
 data 
  
 != 
  
 null 
 ) 
  
 { 
  
 name 
  
 = 
  
 String 
 ( 
  
 Base64 
 . 
 getDecoder 
 (). 
 decode 
 ( 
 message 
 . 
 data 
 !! 
 . 
 toByteArray 
 ( 
 StandardCharsets 
 . 
 UTF_8 
 )), 
  
 StandardCharsets 
 . 
 UTF_8 
 ) 
  
 } 
  
 LOGGER 
 . 
 info 
 ( 
 String 
 . 
 format 
 ( 
 "Hello %s!" 
 , 
  
 name 
 )) 
  
 return 
 ; 
  
 } 
  
 companion 
  
 object 
  
 { 
  
 private 
  
 val 
  
 LOGGER 
  
 = 
  
 Logger 
 . 
 getLogger 
 ( 
 KotlinHelloPubSub 
 :: 
 class 
 . 
 java 
 . 
 name 
 ) 
  
 } 
 }

When developing background functions, you define classes for the events triggering your functions. However, GSON marshalling may not work out of the box for Kotlin, if your event class doesn't follow certain guidelines .

In your Kotlin event class, properties must conform to these guidelines:

They are able to be set to null .
They don't have a default value assigned to them.
They are not delegate properties.

Another approach is to create your event classes in Java, and use them from your Kotlin function class.

Groovy

  import 
  
 com.google.cloud.functions.BackgroundFunction 
 import 
  
 com.google.cloud.functions.Context 
 import 
  
 functions.eventpojos.PubsubMessage 
 import 
  
 java.nio.charset.StandardCharsets 
 import 
  
 java.util.logging.Logger 
 class 
  
 GroovyHelloPubSub 
  
 implements 
  
 BackgroundFunction<PubsubMessage> 
  
 { 
  
 private 
  
 static 
  
 final 
  
 Logger 
  
 LOGGER 
  
 = 
  
 Logger 
 . 
 getLogger 
 ( 
 GroovyHelloPubSub 
 . 
 class 
 . 
 name 
 ) 
  
 @Override 
  
 void 
  
 accept 
 ( 
 PubsubMessage 
  
 message 
 , 
  
 Context 
  
 context 
 ) 
  
 { 
  
 // name's default value is "world" 
  
 String 
  
 name 
  
 = 
  
 "world" 
  
 if 
  
 ( 
 message 
 ?. 
 data 
 ) 
  
 { 
  
 name 
  
 = 
  
 new 
  
 String 
 ( 
 Base64 
 . 
 decoder 
 . 
 decode 
 ( 
 message 
 . 
 data 
 ), 
  
 StandardCharsets 
 . 
 UTF_8 
 ) 
  
 } 
  
 LOGGER 
 . 
 info 
 ( 
 "Hello ${name}!" 
 ) 
  
 return 
  
 } 
 }

Scala

  import 
  
 java 
 . 
 nio 
 . 
 charset 
 . 
 StandardCharsets 
 import 
  
 java 
 . 
 util 
 . 
 Base64 
 import 
  
 java 
 . 
 util 
 . 
 logging 
 . 
 Logger 
 import 
  
 com 
 . 
 google 
 . 
 cloud 
 . 
 functions 
 .{ 
 BackgroundFunction 
 , 
  
 Context 
 } 
 import 
  
 functions 
 . 
 eventpojos 
 . 
 PubsubMessage 
 class 
  
 ScalaHelloPubSub 
  
 extends 
  
 BackgroundFunction 
 [ 
 PubsubMessage 
 ] 
  
 { 
  
 val 
  
 LOGGER 
  
 = 
  
 Logger 
 . 
 getLogger 
 ( 
 this 
 . 
 getClass 
 . 
 getName 
 ) 
  
 override 
  
 def 
  
 accept 
 ( 
 message 
 : 
  
 PubsubMessage 
 , 
  
 context 
 : 
  
 Context 
 ): 
  
 Unit 
  
 = 
  
 { 
  
 // name's default value is "world" 
  
 var 
  
 name 
  
 = 
  
 "world" 
  
 if 
  
 ( 
 message 
  
 != 
  
 null 
 && 
 message 
 . 
 getData 
  
 != 
  
 null 
 ) 
  
 { 
  
 name 
  
 = 
  
 new 
  
 String 
 ( 
 Base64 
 . 
 getDecoder 
 . 
 decode 
 ( 
  
 message 
 . 
 getData 
 . 
 getBytes 
 ( 
 StandardCharsets 
 . 
 UTF_8 
 )), 
  
 StandardCharsets 
 . 
 UTF_8 
 ) 
  
 } 
  
 LOGGER 
 . 
 info 
 ( 
 String 
 . 
 format 
 ( 
 "Hello %s!" 
 , 
  
 name 
 )) 
  
 } 
 }

Deploying the background functions

Kotlin

  gcloud 
  
 functions 
  
 deploy 
  
 kotlin 
 - 
 hello 
 - 
 pubsub 
  
 -- 
 entry 
 - 
 point 
  
 functions 
 . 
 KotlinHelloPubSub 
  
 -- 
 no 
 - 
 gen2 
  
 -- 
 runtime 
  
 java17 
  
 -- 
 trigger 
 - 
 topic 
  
 my 
 - 
 topic 
  
 -- 
 allow 
 - 
 unauthenticated 
  
 -- 
 memory 
  
 512 
 MB

Groovy

  gcloud 
  
 functions 
  
 deploy 
  
 groovy 
 - 
 hello 
 - 
 pubsub 
  
 -- 
 entry 
 - 
 point 
  
 functions 
 . 
 GroovyHelloPubSub 
  
 -- 
 no 
 - 
 gen2 
  
 -- 
 runtime 
  
 java17 
  
 -- 
 trigger 
 - 
 topic 
  
 my 
 - 
 topic 
  
 -- 
 allow 
 - 
 unauthenticated 
  
 -- 
 memory 
  
 512 
 MB

Scala

  gcloud 
  
 functions 
  
 deploy 
  
 scala 
 - 
 hello 
 - 
 pubsub 
  
 -- 
 entry 
 - 
 point 
  
 functions 
 . 
 ScalaHelloPubSub 
  
 -- 
 no 
 - 
 gen2 
  
 -- 
 runtime 
  
 java17 
  
 -- 
 trigger 
 - 
 topic 
  
 my 
 - 
 topic 
  
 -- 
 allow 
 - 
 unauthenticated 
  
 -- 
 memory 
  
 512 
 MB

Test the background examples

You can test the background examples as follows:

Publish a message to your Pub/Sub Topic to trigger your function:

gcloud  
pubsub  
topics  
publish  
my-topic  
--message  
Flurry

Look at the logs:

gcloud  
functions  
logs  
 read 
  
--limit  
 10

You should see something like this, with a message that includes the name you published to the Pub/Sub topic:

 D      my-function  ...  Function execution started
I      my-function  ...  Hello Flurry!
D      my-function  ...  Function execution took 39 ms, finished with status: 'ok'

JVM Languages

HTTP function examples

Kotlin

Groovy

Scala

pom.xml file for HTTP examples

Kotlin

Groovy

Scala

Deploying the HTTP functions

Kotlin

Groovy

Scala

Event-driven function examples

Kotlin

Groovy

Scala

Deploying the background functions

Kotlin

Groovy

Scala

Test the background examples

`pom.xml` file for HTTP examples