This tutorial will show you how to develop and debug a Ruby application using Okteto
Run the following command to deploy the Ruby Sample App:
kubectl apply -f k8s.yml
deployment.apps/hello-world created
service/hello-world created
The dev section of the Okteto Manifest defines how to activate a development container for the Ruby Sample App:
dev:
hello-world:
command: bash
sync:
- .:/opt/app/
forward:
- 8080:8080
- 1234:1234
volumes:
- /usr/local/bundle/cache
The hello-world
key matches the name of the hello world Deployment. The meaning of the rest of fields is:
command
: the start command of the development container.sync
: the folders that will be synchronized between your local machine and the development container.forward
: a list of ports to forward from your development container to localhost in your machine. This is needed to access the port 8080 of your application on localhost and to configure the Ruby remote debugger.volumes
: a list of paths in your development container to be mounted as persistent volumes. For example, this is useful to persist the bundle cache.
Also, note that there is a .stignore
file to indicate which files shouldn't be synchronized to your development container.
This is useful to avoid synchronizing binaries, build artifacts or git metadata.
Next, execute the following command to activate your development container:
okteto up
✓ Images successfully pulled
✓ Files synchronized
Namespace: cindy
Name: hello-world
Forward: 8080 -> 8080
1234 -> 1234
Welcome to your development container. Happy coding!
cindy:hello-world app>
Working in your development container is the same as working on your local machine. Start the application in hot-reload mode by running the following command:
cindy:hello-world app> ruby app.rb
[2022-07-04 16:50:53] INFO WEBrick 1.6.1
[2022-07-04 16:50:53] INFO ruby 2.7.6 (2022-04-12) [x86_64-linux]
== Sinatra (v2.0.8.1) has taken the stage on 8080 for production with backup from WEBrick
[2022-07-04 16:50:53] INFO WEBrick::HTTPServer#start: pid=79 port=8080
Open your browser and load the page http://localhost:8080
to test that your application is running.
You should see the message:
Hello world!
Open the app.rb
file in your favorite local IDE and modify the response message on line 7 to be Hello world from Okteto!. Save your changes.
get "/" do
message = "Hello world from Okteto!"
message
end
Okteto will synchronize your changes to your development container in Kubernetes and Sinatra automatically detects them and reloads your application.
Go back to the browser and reload the page. Your code changes were instantly applied. No commit, build, or push required 😎!
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 Ruby development. If you haven't done it yet, install the Ruby extension available from Visual Studio marketplace. This extension comes with debug definitions covering the default ruby-debug-ide
client setup.
Now, cancel the execution of ruby app.rb
from the development container shell by pressing ctrl + c
. Rerun your application in debug mode:
cindy:hello-world app> rdebug-ide --host 0.0.0.0 app.rb
Fast Debugger (ruby-debug-ide 0.7.0, debase 0.2.4.1, file filtering is supported) listens on 0.0.0.0:1234
Open the Run view in VS Code and run the Connect to okteto debug configuration (or press the F5 shortcut):
{
"version": "0.2.0",
"configurations": [
{
"name": "Connect to okteto",
"type": "Ruby",
"request": "attach",
"remotePort": "1234",
"remoteHost": "localhost",
"remoteWorkspaceRoot": "/opt/app",
"cwd": "${workspaceRoot}"
}
]
}
You should replace the value of
remoteWorkspaceRoot
with wherever your application code is.
Add a breakpoint on app.rb
, line 8. 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, but you can debug it from your local machine without any extra services or tools. Pretty cool no? 😉