Hello World Go Example

Make sure serverless is installed. See installation guide.

Once installed the Serverless CLI can be called with serverless or the shorthand sls command.

$ sls

Commands
* You can run commands with "serverless" or the shortcut "sls"
* Pass "--verbose" to this command to get in-depth plugin info
* Pass "--no-color" to disable CLI colors
* Pass "--help" after any <command> for contextual help

You should also have go and make

It is good practice to organize your go projects within GOPATH, unless using Go modules, to maximize the benefits of go tooling.

1. Create a service

The Serverless Framework includes starter templates for various languages and providers. There are three templates for go.

aws-go

aws-go fetches dependencies using standard go get.

sls create --template aws-go --path myService

aws-go-dep

aws-go-dep uses go dep and requires your project to be in $GOPATH/src.

sls create --template aws-go-dep --path myService

aws-go-mod

aws-go-mod uses standard Go modules and requires your project to be outside $GOPATH and to use Go 1.13+.

sls create --template aws-go-mod --path myService

Using the create command we can specify one of the available templates. For this example use aws-go-dep with the --template or shorthand -t flag.

The --path or shorthand -p is the location to be created with the template service files.

Change directories into 'myService' folder and you can see this project has 2 handler functions: hello and world split into 2 separate go packages (folders):

.
├── hello/
│   └── main.go
├── world/
│   └── main.go

This because a main() function is required as entry point for each handler executable.

2. Build using go build to create static binaries

Run make build to build both functions. Successful build should generate the following binaries:

.
├── bin/
│   |── hello
│   └── world

3. Deploy

sls deploy

This will deploy your function to AWS Lambda based on the settings in serverless.yml.

4. Invoke deployed function

sls invoke -f hello
sls invoke -f world

Invoke either deployed function with command invoke and --function or shorthand -f.

In your terminal window you should see the response from AWS Lambda.

serverless invoke -f hello

{
    "message": "Go Serverless v1.0! Your function executed successfully!"
}

serverless invoke -f world

{
    "message": "Okay so your other function also executed successfully!"
}

Congrats you have deployed and ran your Hello World function!

GitHub
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