opcd

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    open · project · code

Reusable Dev Containers for any project — without modifying the repository.

Table of Contents

• Background
• Install
• Usage
• Configuration
• Template System
• File Injection
• API
• Contributing
• License

---

Background

opcd is a CLI that opens any project in VS Code Dev Containers using reusable, local templates.

Define your environment once and reuse it across projects.

Typical Dev Container workflows involve:

• Copying .devcontainer/ directories between projects
• Recreating environments repeatedly
• Committing configuration to repositories you do not control

opcd separates environment configuration from project code:

• Templates are stored locally
• Projects remain unchanged
• Containers are launched with a single command

---

Install

Dependencies

• VS Code with the Dev Containers extension
• Docker
• devcontainer CLI

pip install opcd

---

Usage

# Open a project (auto-detects template from container history, or uses default)
opcd open ~/projects/my-app

# Open with an explicit template
opcd open ~/projects/my-app opcd

Typical Workflow

opcd template new python-dev
opcd template edit python-dev
opcd open ~/projects/my-app python-dev

Project Switching

opcd list -a -i

Lists containers and allows reopening projects interactively.

Advanced Options

• Multiple template directories
• Verbose debugging (-v)
• Dry runs (--dry-run)
• Custom container paths

Internal Flow

1. Validate project path (must exist)
2. Resolve template (explicit → container history → settings default)
3. Launch VS Code Dev Container
4. Apply file injection rules

---

Configuration

opcd reads settings.json from:

~/.config/opcd/settings.json

Override the config directory:

OPCD_CONF_DIR=/custom/path opcd open ~/projects/my-app

The file is created automatically with defaults on first run.

settings.json

{
  "template_sources": ["~/.local/share/opcd/templates"],
  "default_template": "opcd",
  "template_write_dir": null
}

Key	Description
template_sources	Ordered list of template directories searched when resolving templates.
default_template	Template used when opcd open is called without a template argument and no container history is found. Error if unset.
template_write_dir	Directory where opcd template new writes new templates. null (default) uses the XDG data home: ~/.local/share/opcd/templates. Overridden per-invocation by --path.

---

Template System

Default Location

~/.local/share/opcd/templates/

Configure additional paths via template_sources in settings.json (see Configuration).

---

File Injection

Inject files from the host into the container at startup.

Example

{
  "customizations": {
    "opcd": {
      "cp": [
        {
          "source": "${localEnv:HOME}/.config/myapp",
          "target": "/home/vscode/.config/myapp"
        }
      ]
    }
  }
}

Fields

Field	Required	Description
source	Yes	Host path
target	Yes	Container path
override	No	Skip if target exists (default: false)
owner	No	Requires group
group	No	Requires owner
permissions	No	chmod applied recursively

Source Behavior

• Supports ${localEnv:VAR}
• Supports relative paths from .devcontainer/
• Missing environment variables cause the entry to be skipped

Copy Directory Contents

Use /. suffix:

{
  "source": "${localEnv:HOME}/.config/myapp/.",
  "target": "/home/vscode/.config/myapp/"
}

Copies directory contents instead of the directory itself.

Behavior Rules

• target/ copies into the directory
• Without trailing / copies as a file or directory
• override=false skips existing files
• Ownership and permissions are applied after copying

---

API

Full reference for all opcd commands and flags.

Global Flags

-v, --verbose   Enable debug output
--version       Show version and exit

---

opcd open

opcd open <path> [template] [options]

Open a project in VS Code using a devcontainer template.

Arguments

• <path> — Project directory (must exist)
• [template] (optional) — Template name, path to a devcontainer.json, or path to a directory containing it. Paths must start with ./, ../, /, or ~/. If omitted, opcd resolves in this order:
  1. Most recently running container for this project path
  2. Most recently stopped container for this project path
  3. default_template from settings.json (error if not set)

Options

Option	Default	Description
--dry-run	—	Print resolved configuration and actions without executing
--container-folder <path>	resolved from devcontainer config	Container mount path
--timeout <seconds>	300	Time to wait for container startup

---

opcd list

opcd list [-a] [-i]

List dev containers.

Flag	Description
-a, --all	Include stopped containers
-i, --interactive	Prompt to reopen a listed container

Interactive mode prompts Open [1-N]: — selecting a number reopens the project in VS Code.

---

opcd prune

opcd prune [path] [options]

Remove stopped dev containers. Either [path] or --all-projects is required.

Arguments

• [path] (optional) — Limit pruning to containers for this project directory.

Options

Option	Description
--all-projects	Prune stopped containers across all projects
--include-recent	Also prune the most recently used container (skipped by default)

---

opcd template

opcd template <subcommand>

Manage dev container templates.

---

opcd template new

opcd template new <name> [base] [options]

Create a new template by copying a base template.

Argument	Default	Description
[base]	opcd	Template to copy from

Option	Description
--edit	Launch the new template as a Dev Container in VS Code after creation
--path <dir>	Write the new template into <dir> instead of the configured write target

---

opcd template edit

opcd template edit <template>

Open a template directory in VS Code for editing.

---

opcd template list

opcd template list [--long]

List available templates.

Option	Description
--long	Show description and full path for each template

---

opcd template default

opcd template default [name]

Get or set the default template.

• Without name: prints the current default.
• With name: sets default_template in settings.json.

---

opcd template source

opcd template source <subcommand>

Manage template search paths stored in settings.json.

---

opcd template source list

opcd template source list

Print all configured template search paths, one per line.

---

opcd template source add

opcd template source add <path>

Append <path> to template_sources in settings.json. Prints a notice and exits cleanly if already present.

---

opcd template source remove

opcd template source remove <path>

Remove <path> from template_sources in settings.json. Exits with an error if not found.

---

opcd completion

opcd completion bash
opcd completion zsh
opcd completion fish

Print the shell completion setup command for the given shell.

Add to your shell rc file for persistent completion:

# bash (~/.bashrc)
eval "$(opcd completion bash)"

# zsh (~/.zshrc)
eval "$(opcd completion zsh)"

# fish (~/.config/fish/config.fish)
eval (opcd completion fish)

---

Contributing

Ask questions, report bugs, or request features in Issues.

PRs welcome. Open an issue first for significant changes.

Run tox (or pytest for a single-interpreter run) before submitting.

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License

MIT © Nasser Alansari (dacrystal)

See LICENSE.

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