Getting Started on Okteto Cloud with Go

Okteto Cloud gives instant access to secure Kubernetes namespaces to enable developers to code, build, and run Kubernetes applications entirely in the cloud.

This tutorial will show you how to create an account in Okteto Cloud and how to develop a Go sample application.

Prerequisites

Step 1: Deploy the Go Sample App

Get a local version of the Go Sample App by executing the following commands:

$ git clone https://github.com/okteto/go-getting-started
$ cd go-getting-started

The k8s.yml file contains the Kubernetes manifests of the Go Sample App. Deploy a dev version of the application by executing:

$ kubectl apply -f k8s.yml
deployment.apps "hello-world" created
service "hello-world" created

Open your browser and go to the URL of the application. You can get the URL by logging into Okteto Cloud and clicking on the application's endpoint:

Did you notice that you are accessing your application through an HTTPs endpoint? This is because Okteto Cloud will automatically create them for you when you deploy your application. Cool no ๐Ÿ˜Ž?

Step 2: Activate your development container

With the Go Sample Application deployed, run the following command:

$ okteto up
โœ“ Development container activated
โœ“ Files synchronized
Namespace: cindy
Name: hello-world
Forward: 8080 -> 8080
2345 -> 2345
Welcome to your development container. Happy coding!
okteto>

The okteto up command starts a development container, which means:

  • The Go Sample App container is updated with the docker image okteto/hello-world:golang-dev. This image contains the required dev tools to build, test, debug and run a Go application. Check the Dockerfile to see how it is generated.
  • A file synchronization service is created to keep your changes up-to-date between your local filesystem and your development container.
  • Container ports 8080 (the application) and 2345 (the debugger) are forwarded to localhost.
  • A remote shell is started in your development container. Build, test and run your application as if you were in your local machine.

All of this (and more) can be customized via the okteto.yml manifest file. You can also use the file .stignore to skip files from file synchronization. This is useful to avoid synchronizing build artifacts or git metadata.

To run the application, execute in the development container shell:

okteto> go run main.go
Starting hello-world server...

Go back to the browser, and reload the page to test that your application is running.

Step 3: Develop directly in Okteto Cloud

Open the file main.go in your favorite local IDE and modify the response message on line 17 to be Hello world from Okteto!. Save your changes.

func helloServer(w http.ResponseWriter, r *http.Request) {
fmt.Fprint(w, "Hello world from Okteto!")
}

Okteto will synchronize your changes to your development container. Cancel the execution of go run main.go from the development container shell by pressing ctrl + c. Rerun your application:

okteto> go run main.go
Starting hello-world server...

Go back to the browser and reload the page. Your code changes were instantly applied. No commit, build or push required ๐Ÿ˜Ž!

Step 4: Debug directly in Okteto Cloud

Okteto enables you to debug your applications directly from your favorite IDE. Let's take a look at how that works in VS Code, one of the most popular IDEs for Go development. If you haven't done it yet, install the Go extension available from Visual Studio marketplace.

Cancel the execution of go run main.go from the development container shell by pressing ctrl + c. Rerun your application in debug mode:

okteto> dlv debug --headless --listen=:2345 --log --api-version=2
API server listening at: [::]:2345
2019-10-17T14:39:24Z info layer=debugger launching process with args: [/app/__debug_bin]

In your local machine, open VS Code, and install the Go extension.

The sample application is already configured for remote debugging. Open the Debug view in VS Code and run the Connect to okteto debug configuration (or just press the F5 shortcut) to start the remote debugger:

{
"version": "0.2.0",
"configurations": [
{
"name": "Connect to okteto",
"type": "go",
"request": "attach",
"mode": "remote",
"remotePath": "/app",
"port": 2345,
"host": "127.0.0.1"
}
]
}

Add a breakpoint on main.go, line 17. Go back to the browser, and reload the page. The execution will halt at your breakpoint. You can then inspect the request, the available variables, etc...

Your code is executing in Okteto Cloud, but you can debug it from your local machine without any extra services or tools. Pretty cool no? ๐Ÿ˜‰

Step 5: Redeploy the Go Sample App

Once you are happy with your changes, exit your development container with ctrl + c + ctrl + d.

If you want to keep your changes running, execute the following command in your local shell:

$ okteto push
i Running your build in Okteto Cloud
[+] Building 16.0s (16/16)
...
โœ“ Source code pushed to 'hello-world'

okteto push automatically builds a new image tag using the Okteto Build Service, pushes it to the Okteto Registry and redeploys your application with the new image tag ๐Ÿ’ฅ!

Alternatively, you can also rollback the Go Sample App to its original state (the one before running okteto up) by executing:

$ okteto down
โœ“ Development container deactivated

Next steps

Congratulations, you just developed your first application in Okteto Cloud ๐Ÿš€.

Okteto lets you develop your applications directly in Kubernetes. This way you can:

  • Eliminate integration issues by developing in a realistic environment
  • Test your application end to end as fast as you type code
  • No more CPU cycles wasted in your machine. Develop at the speed of the cloud!

Okteto uses the okteto.yml file to determine the name of your development container, the docker image to use and where to upload your code. Check the Okteto manifest docs to customize your development containers with your own dev tools, images, and dependencies to adapt Okteto to your own application.

Ready to develop your application on Okteto Cloud? Read our step by step tutorial on how to configure an Okteto Pipeline to deploy realistic environments for your application in just one click.

Find more advanced samples with Okteto in this repository or join our #okteto channel in the Kubernetes community Slack to make questions or share your feedback.