Add CUPS print server container for Brother HL-4150CDN

2026-10-18 09:16:37 +02:00
commit 6f3162849b
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+# Spec Delta
+
+## Purpose
+
+Provide a containerized CUPS print server that shares the Brother HL-4150CDN network printer as an AirPrint and IPP printer so clients can print without installing local printer drivers.
+
+## ADDED Requirements
+
+### Requirement: Container image builds with required dependencies
+The container SHALL include CUPS, Avahi/mDNS, DBus, and required 32-bit runtime libraries to run Brother HL-4150CDN i386 binaries.
+
+#### Scenario: Image contains CUPS
+- **WHEN** the image is built
+- **THEN** CUPS is installed and available at /usr/sbin/cupsd
+
+#### Scenario: Image supports 32-bit Brother binaries
+- **WHEN** the image is built
+- **THEN** required 32-bit libraries are present for the Brother i386 filters
+
+### Requirement: Brother HL-4150CDN driver is installed in container
+The container SHALL install the Brother HL-4150CDN CUPS wrapper, PPD, LPR/filter components from the provided driver artifacts.
+
+#### Scenario: Driver files present
+- **WHEN** the container image is built
+- **THEN** the HL-4150CDN PPD and Brother filters are installed in standard system locations
+
+#### Scenario: CUPS recognizes HL-4150CDN
+- **WHEN** CUPS starts with the driver installed
+- **THEN** CUPS is able to use the HL-4150CDN PPD
+
+### Requirement: Printer is shared and discoverable
+The system SHALL share the Brother HL-4150CDN printer over IPP and make it discoverable via AirPrint (mDNS/DNS-SD) on the container network.
+
+#### Scenario: IPP printer is shared
+- **WHEN** CUPS runs in the container
+- **THEN** the printer is shared via IPP for network clients
+
+#### Scenario: AirPrint discovery
+- **WHEN** Avahi runs alongside CUPS
+- **THEN** the printer is advertised via AirPrint so macOS/iOS clients can discover it without driver installation
+
+### Requirement: Runtime configuration is exposed
+The container SHALL expose CUPS on port 631 and mDNS on UDP port 5353.
+
+#### Scenario: CUPS port exposed
+- **WHEN** the container runs
+- **THEN** port 631 is available for CUPS administration and IPP
+
+#### Scenario: mDNS port exposed
+- **WHEN** the container runs
+- **THEN** UDP port 5353 is available for AirPrint discovery
+
+### Requirement: No client drivers required
+The shared printer SHALL be exposed in a way that client devices can print without installing vendor printer drivers.
+
+#### Scenario: AirPrint compatibility
+- **WHEN** a client discovers the printer via AirPrint
+- **THEN** the client uses native IPP/AirPrint drivers
+
+### Requirement: Printer endpoint and advertised name are configurable at runtime
+The container SHALL accept the network printer address and the advertised printer name through environment variables so the same image can target a different printer or name without rebuilding.
+
+#### Scenario: Printer IP is provided
+- **WHEN** the container is started with `PRINTER_IP` set
+- **THEN** a device URI is derived from that address and the Brother HL-4150CDN queue is created pointing at it
+
+#### Scenario: Printer protocol is selected
+- **WHEN** the container is started with `PRINTER_IP` and `PRINTER_PROTOCOL`
+- **THEN** the device URI uses that protocol (lpd, socket or ipp)
+
+#### Scenario: Full URI override
+- **WHEN** `PRINTER_URI` is set
+- **THEN** it is used as the device URI and `PRINTER_IP` is ignored
+
+#### Scenario: Custom advertised name
+- **WHEN** the container is started with `PRINTER_NAME`
+- **THEN** the CUPS queue uses that name and it is the name advertised via AirPrint/DNS-SD
+
+#### Scenario: Custom CUPS description
+- **WHEN** the container is started with `PRINTER_DESCRIPTION`
+- **THEN** the queue's CUPS Description (Info) is set to that value