containerfile

name	containerfile
version	1.1
last_updated	2026-08-08
id	containerfile
one_line_purpose	Modify and locally test the common Containerfile build.
entry_point	docs/skills/containerfile/SKILL.md
category	ci-ops
mcp_compliance_level	partial
optimization_status	draft
status	active
dependencies	[]
tags	["containerfile","build","oci"]
description	Containerfile build structure and local testing. Use when modifying the Containerfile, adding binaries, updating wallpaper sources, or using just overlay.
metadata	{"type":"reference"}

Containerfile — common OCI layer build

When to Use

Use when modifying the Containerfile, adding new external binaries, updating wallpaper sources, changing the umotd/uwelcome version pins, or running just overlay to test system_files/ changes locally.

When Not to Use

Do not use this skill for changes that only affect system_files/ content without touching the Containerfile build stages, or for downstream image Containerfiles outside projectbluefin/common.

Build Stages Overview

The Containerfile uses four named stages:

Stage	Purpose
umotd-build	Go builder for the MOTD tips binary
uwelcome-build	Go builder for the CLI welcome banner binary
build	Downloads and assembles all artifacts into /out/
ctx	Scratch image: the OCI layer consumed by downstream builds

See references/build-stages.md for the full stage details, wallpaper source caveat, and ujust completion generation.

Key Rules

• Never download a pre-built binary for umotd/uwelcome — use the Go builder stage pattern.
• Never add a curl download without a paired sha256sum -c check.
• Git checkout pins must be commit SHAs, not tags or branch names.
• Place shared binaries in /out/shared/, Bluefin-specific in /out/bluefin/.

Red Flags

• checkout tags/... or --branch in a Go builder stage — tags are mutable.
• A curl block without an inline sha256sum -c.
• Editing generated ujust completions directly instead of fixing the sed pattern.
• Using ghcr.io/projectbluefin/ for the wallpaper source (it is ).