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Your Cloud Run function runs in an environment consisting of an
operating system version with add-on packages, language support, and
theGo Functions Frameworklibrary that supports and invokes your function. This environment is identified
by the language version, and is known as the runtime ID.
Function preparation
You can prepare a function directly from the Google Cloud console or write it on
your local machine and upload it. To prepare your local machine for Go
development, seeSet up a Go development environment.
You can select one of the supported Go runtimes for your function during
deployment.
You can select a runtime version using the Google Cloud console, or the
gcloud CLI. Click the tab for instructions on using the tool of
your choice:
gcloud
Specify theGo base imagefor your function using the--base-imageflag,
while deploying your function. For example:
gcloud run deployFUNCTION\
--source . \
--functionFUNCTION_ENTRYPOINT\
--base-image go125
Replace:
FUNCTIONwith the name of the function you are
deploying. You can omit this parameter entirely,
but you will be prompted for the name if you omit it.
FUNCTION_ENTRYPOINTwith the entry point to your function in
your source code. This is the code Cloud Run executes when your
function runs. The value of this flag must be a function name or
fully-qualified class name that exists in your source code.
You can select a runtime version when you create or update a Cloud Run function in the Google Cloud console. For detailed
instructions on deploying a function, seeDeploy functions in Cloud Run.
To select a runtime in the Google Cloud console when you create a function, follow these steps:
In the Google Cloud console, go to the Cloud Run page:
ClickCreate, and wait for Cloud Run to create the service
using a placeholder revision.
The console will redirect you to theSourcetab where you can see the source code of your function. ClickSave and redeploy.
For detailed instructions on updating the runtime version after your function is
deployed, seeRe-deploy new source code.
Source code structure
For Cloud Run functions to find your function's definition, your
source code must follow a specific structure. SeeWrite Cloud Run functionsfor more
information.
Specify dependencies
Cloud Run functions in Go must provide all of their dependencies
either with Go modules and ago.modfile, or with avendordirectory. For
more information, seeSpecify dependencies in Go.
Environment variables
Your Go runtime automatically sets certain environment variables for your function
to use as needed. For details, seeConfigure environment variables.
Contexttype
Go'scontextpackagedefines theContexttype, which carries deadlines, cancellation signals, and other request-scoped
values across API boundaries and between processes.
The following code shows an example of context access by a
Pub/Sub client:
// Package helloworld provides a set of Cloud Functions samples.packagehelloworldimport("context""fmt""log""github.com/GoogleCloudPlatform/functions-framework-go/functions""github.com/cloudevents/sdk-go/v2/event")funcinit(){functions.CloudEvent("HelloPubSub",helloPubSub)}// MessagePublishedData contains the full Pub/Sub message// See the documentation for more details:// https://cloud.google.com/eventarc/docs/cloudevents#pubsubtypeMessagePublishedDatastruct{MessagePubSubMessage}// PubSubMessage is the payload of a Pub/Sub event.// See the documentation for more details:// https://cloud.google.com/pubsub/docs/reference/rest/v1/PubsubMessagetypePubSubMessagestruct{Data[]byte`json:"data"`}// helloPubSub consumes a CloudEvent message and extracts the Pub/Sub message.funchelloPubSub(ctxcontext.Context,eevent.Event)error{varmsgMessagePublishedDataiferr:=e.DataAs(&msg);err!=nil{returnfmt.Errorf("event.DataAs: %w",err)}name:=string(msg.Message.Data)// Automatically decoded from base64.ifname==""{name="World"}log.Printf("Hello, %s!",name)returnnil}
[[["Easy to understand","easyToUnderstand","thumb-up"],["Solved my problem","solvedMyProblem","thumb-up"],["Other","otherUp","thumb-up"]],[["Hard to understand","hardToUnderstand","thumb-down"],["Incorrect information or sample code","incorrectInformationOrSampleCode","thumb-down"],["Missing the information/samples I need","missingTheInformationSamplesINeed","thumb-down"],["Other","otherDown","thumb-down"]],["Last updated 2025-09-04 UTC."],[],[],null,["# The Go runtime\n\nYour Cloud Run function runs in an environment consisting of an\noperating system version with add-on packages, language support, and\nthe [Go Functions Framework](https://github.com/GoogleCloudPlatform/functions-framework-go)\nlibrary that supports and invokes your function. This environment is identified\nby the language version, and is known as the runtime ID.\n\nFunction preparation\n--------------------\n\nYou can prepare a function directly from the Google Cloud console or write it on\nyour local machine and upload it. To prepare your local machine for Go\ndevelopment, see [Set up a Go development environment](/go/docs/setup).\n\nSupported Go runtimes and base images\n-------------------------------------\n\n| **Note:** Go's [release policy](https://go.dev/doc/devel/release#policy) states that each major Go release is supported until there are two newer major releases. Thus, depending on when newer versions of Go are made publicly available, key dates such as end of support, deprecation, and decommission might be postponed.\n\nSelect your runtime\n-------------------\n\nYou can select one of the supported Go runtimes for your function during\ndeployment.\n\nYou can select a runtime version using the Google Cloud console, or the\ngcloud CLI. Click the tab for instructions on using the tool of\nyour choice: \n\n### gcloud\n\nSpecify the [Go base image](/run/docs/configuring/services/runtime-base-images#how_to_obtain_base_images) for your function using the `--base-image` flag,\nwhile deploying your function. For example: \n\n gcloud run deploy \u003cvar translate=\"no\"\u003eFUNCTION\u003c/var\u003e \\\n --source . \\\n --function \u003cvar translate=\"no\"\u003eFUNCTION_ENTRYPOINT\u003c/var\u003e \\\n --base-image go125\n\nReplace:\n\n- \u003cvar translate=\"no\"\u003eFUNCTION\u003c/var\u003e with the name of the function you are\n deploying. You can omit this parameter entirely,\n but you will be prompted for the name if you omit it.\n\n- \u003cvar translate=\"no\"\u003eFUNCTION_ENTRYPOINT\u003c/var\u003e with the entry point to your function in\n your source code. This is the code Cloud Run executes when your\n function runs. The value of this flag must be a function name or\n fully-qualified class name that exists in your source code.\n\nFor detailed instructions on deploying a function using the gcloud CLI, see [Deploy functions in Cloud Run](/run/docs/deploy-functions#gcloud).\n\n### Console\n\nYou can select a runtime version when you create or update a Cloud Run function in the Google Cloud console. For detailed\ninstructions on deploying a function, see [Deploy functions in Cloud Run](/run/docs/deploy-functions#deploy-functions).\n\nTo select a runtime in the Google Cloud console when you create a function, follow these steps:\n\n1. In the Google Cloud console, go to the Cloud Run page:\n\n [Go to Cloud Run](https://console.cloud.google.com/run)\n2. Click **Write a function**.\n\n3. In the **Runtime** list, select a Go runtime version.\n\n4. Click **Create**, and wait for Cloud Run to create the service\n using a placeholder revision.\n\n5. The console will redirect you to the **Source**\n tab where you can see the source code of your function. Click **Save and redeploy**.\n\nFor detailed instructions on updating the runtime version after your function is\ndeployed, see\n[Re-deploy new source code](/run/docs/deploy-functions#update-code-functions).\n\nSource code structure\n---------------------\n\nFor Cloud Run functions to find your function's definition, your\nsource code must follow a specific structure. See\n[Write Cloud Run functions](/run/docs/write-functions#go) for more\ninformation.\n\nSpecify dependencies\n--------------------\n\nCloud Run functions in Go must provide all of their dependencies\neither with Go modules and a `go.mod` file, or with a `vendor` directory. For\nmore information, see [Specify dependencies in Go](/run/docs/runtimes/go-dependencies).\n\nEnvironment variables\n---------------------\n\nYour Go runtime automatically sets certain environment variables for your function\nto use as needed. For details, see\n[Configure environment variables](/run/docs/configuring/services/environment-variables).\n\n`Context` type\n--------------\n\n[Go's `context` package](https://golang.org/pkg/context/) defines the `Context`\ntype, which carries deadlines, cancellation signals, and other request-scoped\nvalues across API boundaries and between processes.\n\nThe following code shows an example of context access by a\nPub/Sub client: \n\n\n // Package helloworld provides a set of Cloud Functions samples.\n package helloworld\n\n import (\n \t\"context\"\n \t\"fmt\"\n \t\"log\"\n\n \t\"github.com/GoogleCloudPlatform/functions-framework-go/functions\"\n \t\"github.com/cloudevents/sdk-go/v2/event\"\n )\n\n func init() {\n \tfunctions.CloudEvent(\"HelloPubSub\", helloPubSub)\n }\n\n // MessagePublishedData contains the full Pub/Sub message\n // See the documentation for more details:\n // https://cloud.google.com/eventarc/docs/cloudevents#pubsub\n type MessagePublishedData struct {\n \tMessage PubSubMessage\n }\n\n // PubSubMessage is the payload of a Pub/Sub event.\n // See the documentation for more details:\n // https://cloud.google.com/pubsub/docs/reference/rest/v1/PubsubMessage\n type PubSubMessage struct {\n \tData []byte `json:\"data\"`\n }\n\n // helloPubSub consumes a CloudEvent message and extracts the Pub/Sub message.\n func helloPubSub(ctx context.Context, e event.Event) error {\n \tvar msg MessagePublishedData\n \tif err := e.DataAs(&msg); err != nil {\n \t\treturn fmt.Errorf(\"event.DataAs: %w\", err)\n \t}\n\n \tname := string(msg.Message.Data) // Automatically decoded from base64.\n \tif name == \"\" {\n \t\tname = \"World\"\n \t}\n \tlog.Printf(\"Hello, %s!\", name)\n \treturn nil\n }"]]
