Getting Started on Okteto Cloud with Go

Okteto Cloud gives you free access to secure Kubernetes namespaces, fully integrated with remote development capabilities. Develop your Kubernetes applications in Okteto Cloud and forget about slow and tedious local development forever.

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: Start your remote development environment

We are going to use the dev version of the Go Sample App we just deployed as our remote development environment. To do that, run the following command:

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

The okteto up command starts a remote development environment 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 application pods.
  • Container ports 8080 (the application) and 2345 (the debugger) are forwarded to localhost.
  • A remote shell is started in your remote development environment. 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 remote 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 remote development environnments. Cancel the execution of go run main.go from the remote 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 remote 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 environment 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 the development environment '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 environment deactivated

Next steps

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

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

  • Reduce local setup and eliminate integration issues by developing the same way your application runs in production
  • Test your application as fast as you type code, without typing either docker or kubectl in your inner loop cycle
  • No more CPU cycles wasted in your machine. Hardware and network just limited by the power of the cloud

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

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.