GO RESTFUL — #3
A Complete Go Development Environment With Docker and VS Code
Last time, I created a simple script launching Docker container that can sync and execute Go source code from my local machine. But I haven’t yet figured it out how to support IntelliSense and debugging, which are critical for development. Let’s do that in this article.
Considerations
I was a bit worried when I was researching solutions for this because it heavily depends on vendors of code editors/IDEs supporting working within containers. Luckily, there are two popular editors supporting it: GoLand and Visual Studio Code (or VS Code).
GoLand support looks pretty mature because it has been there for a while (originating with IntelliJ). However, this feature is only applicable in the purchased version.
The VS Code Remote-Containers extension has just recently released, so it is not as mature as GoLand. Nevertheless, the extension is officially developed and maintained by Microsoft (not open-source) and is planned to be used in a lot of future services as a web companion IDE or cloud IDE — so it is very promising. At the time writing this article, the features set looks good enough for getting started, too. Let’s go with VS Code.
Apparently, we can use Vim directly within the container and install awesome plugins into it. However, it would be my last take because I set this for not just me but my team (and yours too), and Vim’s learning curve is very heavy for most developers.
VS Code Remote-Containers
Concept
VS Code Remote-Containers is an extension that helps developers work with their VS Code UI as normal, but all commands and actions are propagated and executed inside containers. It’s actually like you’re TeamViewer-ing into a container and using VS Code within it.
VS Code implementation is strong and abstract enough that most of the extensions still work as is.
With that concept, we can containerize environment for pretty much every kind of development, not just Go.
Recipe
Install VS Code Remote-Containers extension.
Write a Dockerfile defining your image with packages and tools required to run and debug your application.
Create a .devcontainer.json at your workspace root (next to .vscode/ directory) referencing the Dockerfile.
{
"dockerFile": "Dockerfile",
"extensions": [
"ms-vscode.go"
]
}Open the folder containing your .devcontainer.json file with VS Code. VS Code will automatically detect it and ask you to reopen the project in container mode.
Then, VSCode will build Docker images and containers based on your Dockerfile (only for the first time) and set up some additional required packages so that it can work containerizedly.
After the process is finished, you are able to use VS Code as normal and have everything actually run inside containers.
Above example shows that though I do not even have go runtime installed on my local machine, I can execute Go code from my VS Code and access executing server from my Safari. Everything is done inside containers.
Implementation
Following the concept and recipe mentioned above, I create a Dockerfile.
The image is based on the officialgolang image so it can support go out-of-the-box. Then I install several different tools required by Go VS Code extension to achieve IntelliSense, linting, and debugging features.
Then I write a .devcontainer.json file.
It simply refers to the Dockerfile and lists all the extensions that VS Code should install into attached containers. It also sets port mapping from my local machine to my containers and vice versa so that I can test my application directly from my browser.
Result
I was able to write code with all of IntelliSense’s features, such as autocompletion, auto imports, code navigation, etc.
I was able to run the application without Go runtime installed on my local machine. Thanks to port mapping, I can test my application directly with my Safari, too.
I was able to use awesome debugging features supported by Go VS Code extension.
Limitations
I pretty much have everything I need. However, there’re still some limitations that I feel a bit annoying:
- I have to work around a bit to be able to use VS Code Git Push command, which requires my SSH credentials bound to the containers.
- I could not do GPG sign my commit using VS Code Git Commit command. It’s possible but it requires quite a lot of work to be able to forward GPG commands from containers to host machines.
