A simple tutorial of deployment of Go application using GAE

Manato Kuroda

Dec 6, 2019·5 min read

I’ve introduced how to deploy the Go application using GKE and Spinnaker in another post. This post will show you how to deploy it with GAE on Standard.

Example repo

You can view the example code at:

Set up Go app

First off, we prepare a very simple Go app just responding to Hello Go App!

Create a main.go :

Run it:

go run main.go

See it at http://localhost:8080:

Set up Cloud SDK

To quickly start off GCP, we use SDK provided in Google.

Go to an install page and follow the instruction to set it up:

After installation, let’s initialize gcloud account:

gcloud init

After that, you can see the configuration list:

$ gcloud config list                                                           [core]
account = xxx@gmail.com
disable_usage_reporting = TrueYour active configuration is: [default]

Make sure your account is activated:

$ gcloud auth list
                                                
Credentialed Accounts
ACTIVE  ACCOUNT
*       xxx@gmail.comTo set the active account, run:
$ gcloud config set account `ACCOUNT`

Create a project

Create a project with an id which should be unique. In this post we use golang-deploy-gae but you can name it whatever you want.

gcloud projects create golang-deploy-gae

Initialize App Engine

Initialize GAE:

gcloud app create

Select your regions where you want App Engine application located.

Please choose the region where you want your App Engine applicationlocated:[1] asia-east2    (supports standard and flexible)[2] asia-northeast1 (supports standard and flexible)[3] asia-northeast2 (supports standard and flexible)[4] asia-south1   (supports standard and flexible)[5] australia-southeast1 (supports standard and flexible)[6] europe-west   (supports standard and flexible)[7] europe-west2  (supports standard and flexible)[8] europe-west3  (supports standard and flexible)[9] europe-west6  (supports standard and flexible)[10] northamerica-northeast1 (supports standard and flexible)[11] southamerica-east1 (supports standard and flexible)[12] us-central    (supports standard and flexible)[13] us-east1      (supports standard and flexible)[14] us-east4      (supports standard and flexible)[15] us-west2      (supports standard and flexible)

And you cannot change an app’s region once it has been set.

Enable a billing account

To use some Google API, we need to enable billing settings.

If you haven’t had billing account, set it up first:

Make sure of your billing account:

$ gcloud beta billing accounts list
ACCOUNT_ID            NAME              OPEN  MASTER_ACCOUNT_ID
xxxxx-xxxxx-xxxxx  xxxx  True

Next, hook your project up to your billing account:

gcloud beta billing projects link golang-deploy-gae --billing-account {ACCOUNT_ID}

ACCOUNT_ID is supposed to be the billing account that you’ve got above.

You’ll get like this:

billingAccountName: billingAccounts/xxxxx-xxxxx-xxxxx
billingEnabled: true
name: projects/golang-deploy-gae/billingInfo
projectId: golang-deploy-gae

Install App Engine Extension for Go

Install the gcloud command that includes the GAE extension for Go:

gcloud components install app-engine-go

Set up a configuration file

Configure the App engine app’s settings by creating the app.yaml file. The file should contain at least runtime: go . You can see the details on docs.

Create a app.yaml in the root directory:

# app.yamlruntime: go113

It indicates that we’re using the Go 1.3 runtime. If you would like to use Go 1.12, replace it with go112 .

Deploying an app to GAE

Let’s deploy the app on GAE by running the command:

gcloud app deploy

After that, view the page by running the command:

gcloud app browse

Versioning app

Now that we’ve deployed the app on GAE and it can be accessed at https://[YOUR_PROJECT_ID].appspot.com . In an actual case, you probably need several environments such as staging environment, testing environment (QA) and production environment.

Let’s assume that we need staging environment on GAE.

Create staging version by running the command:

gcloud app deploy --version staging --no-promote -q

—-version option will create a specific versioning environment at https://[VERSION]-dot-[YOUR_PROJECT_ID].appspot.com and it will receive the all traffic immediately at https://[YOUR_PROJECT_ID].appspot.com as staging environment. We don’t want it to be switched immediately so add --no-promote which will disable the behavior. More options can be seen in the docs.

You can view the staging at GCP console:

And you also see the progress bar at Traffic Allocation column. Now that another version 20191206t092042 has 100% which means that it receives all traffic as https://[YOUR_PROJECT_ID].appspot.com .

Let’s access https://staging-dot-[YOUR_PROJECT_ID].appspot.com and you’ll see Hello Go App! .

If you want to change the traffic, you can switch it by running the command:

gcloud app services set-traffic default --splits staging=1 -q

And you’ll see that it switched:

Conclusion

We’ve done with deploying the Go app on GAE in this post. GAE provides two environments, Standard and Flexible and you can choose simultaneously to use both environments as microservices architecture. The differences are in docs. I think you might want to start off Standard environment and eventually when you need it to be more flexible as no vendor lock-in, you can set it up as Flexible or split it into Standard and Flexible as microservices.

Hope you’ll find it useful.

A full final codebase is at: