juergen
adaa11e416
Moves the completed change to openspec/changes/archive/2026-10-18-add-cups-printserver-container/ and syncs the printserver/cups capability into openspec/specs/.
58 lines
2.4 KiB
Markdown
58 lines
2.4 KiB
Markdown
# Proposal
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## Why
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Run a Podman container that shares the Brother HL-4150CDN network printer over
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IPP/AirPrint, so clients on macOS, iOS/iPadOS, Linux and Windows can print.
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The HL-4150CDN already emulates BR-Script3 (PostScript 3) and accepts PostScript
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on its AppSocket/LPD ports, so the container can forward PostScript directly to
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the printer instead of shipping Brother's 32-bit Linux CUPS wrapper plus
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Ghostscript rasterisation. This removes the i386 dependency, the multiarch
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runtime and the fragile vendor filter chain.
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The previous approach (Brother Linux `.deb` packages) turned out not to work in
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`debian:bookworm-slim`: the vendor filter `filterhl4150cdn` needs `file` (with
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`a2ps` as a fallback), which are not installed, so it exits with an error and
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produces no output. The official BR-Script3 PPD avoids that entire code path.
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## What Changes
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- Create a Containerfile for Podman based on Debian stable running CUPS, Avahi
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and D-Bus (no i386 multiarch).
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- Install Brother's official **BR-Script3 PPD** (committed under
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`assets/Brother HL-4150CDN/ppd/`) so CUPS emits device options — paper source
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(tray), duplex and colour/mono, plus media type, print quality, toner save and
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secure print — as PostScript `setpagedevice`.
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- Point the queue at the printer with a raw AppSocket URI (`socket://<ip>:9100`)
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by default.
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- Convert incoming client formats (URF/Apple Raster, PWG Raster, PDF, PostScript)
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to PostScript inside CUPS and pass them through to the printer's PostScript
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interpreter.
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- Share the queue over IPP and advertise it via mDNS/DNS-SD (Avahi/AirPrint).
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- Keep runtime configuration (printer address, protocol, queue name) in
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environment variables.
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- Document the supported client matrix.
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## Capabilities
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### New Capabilities
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- `printserver/cups`: Containerised CUPS print server which shares the Brother
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HL-4150CDN over IPP/AirPrint and prints by sending PostScript (BR-Script3)
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directly to the printer.
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### Modified Capabilities
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None
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## Impact
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- Containerfile plus supporting `cupsd.conf` and `entrypoint.sh` in the
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repository root.
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- Uses `assets/Brother HL-4150CDN/ppd/BR4150_2.PPD`.
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- Runtime ports: CUPS/IPP (631/tcp), mDNS/DNS-SD (5353/udp).
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- No 32-bit runtime libraries; the image no longer depends on the host CPU
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architecture.
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- Windows clients install Brother's own BR-Script3 Windows driver client-side.
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- The unused Brother Linux `.deb` packages previously under
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`assets/Brother HL-4150CDN/` have been removed.
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