Devcontainer CLI (NVIM Plugin)

Develop your next Repo in a Devcontainer using nvim thanks to the Devconatiner CLI and this plugin

As you can see in the GIF above, guake with tmux is being used. Any of the ones recommended here would work. For dotfiles setup I created a version of my dotfiles that doesn't have any private submodules. These dotfiles are probably more than what anyone would want, but if feel free to use them. The one gotcha with them is that it requires the environment variable DEV_WORKSPACE to be set. I would recommend looking at the devcontainer-cli branch of my dotfiles. The install.sh script ends up calling script/devcontainer-cli which is quite simple, but should get you some pretty good ideas of how things can be setup.

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Intro

First, what problem is this plugin trying to solve?

Situation:

Your favorite editor is nvim and you are currently developing a containerized application (using Docker).

Problem:

Your team is using a devcontainer (or a docker container) and you want to still use nvim with LSP and DAP (among other plugins), but you don't want to have to run all the cumbersome commands.

Solution:

There are multiple IDEs out there who give you the possibility to execute themself inside the Docker container you are developing, fixing the problems above, but there is nothing which works out-of-the-box for nvim. Recently, Microsoft opened the command line tool, (Devconatiner CLI), which allows developers to run devcontainers without VScode.

The current nvim plugin aims to take advantage of devcontainer-cli for creating your own local development environment on top of a containerized applications. This plugin allows you use LSP capabilities for external modules (installed inside the Docker container), and also debug your application (DAP).

But, what is happening under the hood?

1. First, devcontainer-cli is used for setting up your devcontainer, building the image based on the instructions defined in your devcontainer.json and initializing a container based on such image.
2. Once the container is running, your dotfiles are installed in the docker container together with a set of dependencies. To install any dependencies you need either the dotfiles setup script will need to do that or you can use devcontainer features to install them. A very nice devcontainer feature that can do this is apt package.
3. The last step is connecting inside the container via devcontainer exec (here).

The main thing this plugin does is bringup your devcontainer and execute commands via a convenient interface. It attempts to stay out of your way and allows you to do things as you wish, but gives you the tools to do that easily.

Inspiration:

This plugin has been inspired by the work previously done by arnaupv, esensar and by jamestthompson3. The main difference between this version and arnaupv is that it tries to not make assumptions about how you work.

Dependencies

• docker
• devcontainer-cli
• toggleterm

🔧 Installation

• lazy.nvim

{
  "erichlf/devcontainer-cli.nvim",
  dependencies = { 'akinsho/toggleterm.nvim' },
  keys = {
    -- stylua: ignore
    {
      "<leader>Du",
      ":DevcontainerUp<CR>",
      desc = "Bring up the DevContainer",
    },
    {
      "<leader>Dc",
      ":DevcontainerConnect<CR>",
      desc = "Connect to DevContainer",
    },
    {
      "<leader>Dd",
      ":DevcontainerDown<CR>",
      desc = "Kill the current DevContainer",
    },
    {
      "<leader>De",
      ":DevcontainerExec direction='vertical' size='40'<CR>",
      desc = "Execute a command in DevContainer",
    },
    {
      "<leader>Db",
      ":DevcontainerExec cd build && make<CR>",
      desc = "Execute build command in DevContainer",
    },
    {
      "<leader>Dt",
      ":DevcontainerExec cmd='cd build && make test' direction='horizontal'<CR>",
      desc = "Execute test command in DevContainer",
    },
    {
      "<leader>DT",
      "<CMD>DevContainerToggle<CR>",
      desc = "Toggle the current DevContainer Terminal"
    },
  },
  init = function()
    local opts = {
      -- whather to verify that the final devcontainer should be run
      interactive = false,
      -- search for the devcontainer directory closest to the root in the
      -- directory tree
      toplevel = true,
      -- Remove existing container each time DevcontainerUp is executed
      -- If set to True [default_value] it can take extra time as you force to
      -- start from scratch
      remove_existing_container = true,
      -- By default, if no extra config is added, following nvim_dotfiles are
      -- installed: "https://github.com/erichlf/dotfiles"
      -- This is an example for configuring other dotfiles inside the docker container
      dotfiles_repository = "https://github.com/erichlf/dotfiles.git",
      dotfiles_branch = "devcontainer-cli", -- branch to clone from dotfiles_repository`
      dotfiles_targetPath = "~/dotfiles", -- location to install dotfiles
      -- script to run after dotfiles are cloned
      dotfiles_intallCommand = "install.sh", 
      shell = "bash", -- shell to use when executing commands
      -- The particular binary to use for connecting to in the devcontainer
      -- Most likely this should remain nvim
      nvim_binary = "nvim",
      -- Set the logging level for console (notifications) and file logging. 
      -- The available levels are trace, debug, info, warn, error, or fatal.
      -- Set the log level for file logging
      log_level = "debug",
      -- Set the log level for console logging
      console_level = "info",
    }
    require('devcontainer-cli').setup(opts)
  end,
}

The default_config can be found here.

How to use?

There are 3 main commands: :DevcontainerUp, :DevcontainerExec, and :DevcontainerConnect.

1. First, you should be in the main direcotry or subdirectory of your project container you .devcontainer directory. This file is used by the Devcontainer CLI. As a first approach you can copy-paste the .devcontainer folder of the current project and adapt it for your repo. You can also find more information about the devcontainer.json file here.
2. Then open a nvim session and execute the first command: DevcontainerUp, which will create the image based on your .devcontainer\devcontainer.json. Once created it will initialize a container with the previously created image, and then clone your dotfiles, and finally run the specified setup script. The new devcontainer running can be easily checked with the following command: docker ps -a.
3. If the process above finishes successfully, you can choose to close the current nvim session and open a new session within the devcontainer via the command: :DevcontainerConnect. Alternatively, you could choose to continue working in your current session and run commands in the devcontainer via DevcontainerExec.

During execution using DevcontainerUp or DevcontainerExec it is possible to toggle the terminal via t while in normal mode and then to bring it back you can run :DevContainerToggle. Additionally you could bring it back through :TermSelect.

During the execution of a Devcontainer process you can also type q or <esc> to kill the process and exit the terminal window.

Tests

Tests are executed automatically on each PR using Github Actions.

In case you want to run Github Actions locally, it is recommended to use act. And then execute:

act -W .github/workflows/default.yml

Another option would be to connect to the devcontainer following the How to use? section. Once connected to the devcontainer, execute:

make test

FEATUREs (in order of priority)

1. Capability to create and run a devcontainer using the Devconatiner CLI.
2. Capability to attach in a running devcontainer.
3. The floating window created during the devcontainer Up process (:DevcontainerUp<cr>) is closed when the process finishes successfully.
4. Give the possibility of defining custom dotfiles when setting up the devcontainer
5. Add unit tests using plenary.busted lua module.
6. Create a logger.
7. Convert bash scripts in lua code.