S08.03: UDP syslog from FreeRTOS reaches the oracle

[DavidCozens]

Parent epic: #10 (E08: RTOS Examples)

Scope

Wire FreeRTOS-Plus-TCP UDP into the SolidSyslog UDP path so the existing UDP-side BDD scenarios pass against the FreeRTOS-on-QEMU target — using the same stdin contract that the Linux examples (Example/SingleTask, Example/Threaded) use to receive scenario commands.

Deliverables:

• FreeRTOS example application under Example/FreeRtos/ that:
  • Initialises FreeRTOS-Plus-TCP with a static IP suitable for QEMU networking.
  • Reads scenario commands from a stdin contract identical to the existing examples.
  • Sends them via SolidSyslogUdpSender.
• A new SolidSyslogFreeRtosDatagram implementation of the SolidSyslogDatagram extension point, wrapping the FreeRTOS-Plus-TCP socket API.
• BDD harness updated so the target (Linux example vs FreeRTOS-on-QEMU) is parameterised; existing UDP scenarios run unchanged against the QEMU target.
• Oracle wiring: the existing syslog-ng oracle is reused; only the QEMU networking glue is new (e.g. -netdev user with port forwarding, or a TAP device).

Sliced as: #299 (slice 1) → #290 (slice 2) → #292 (slice 3a) → #295 (slice 3b.1) → #298 (slice 3b.1.5) → #296 (slice 3b.2) → #302 (slice 4) → #304 (slice 5). Slice 5 landed the BDD harness; the per-feature acceptance below is the work of follow-up slices that remove the @freertoswip tags one by one.

Acceptance criteria — BDD scenarios pass against QEMU

• syslog.feature — walking-skeleton end-to-end. (Tagged @freertoswip: composite assertion includes system hostname, current timestamp, and PID of example program — FreeRTOS uses literal FreeRtosExample, the RFC 5424 publication-date placeholder, and PROCID 1.)
• header_fields.feature — RFC 5424 header fields. (1 of 3 scenarios passing today: App name matches the example program. Hostname and PID scenarios tagged @freertoswip for the same hardcoded-values reason.)
• message_fields.feature — message body / MSG field. (Tagged @freertoswip: scenarios use --message-id / --message cmdline args; FreeRTOS has no getopt port — needs cmdline-flag → set NAME VALUE translation in the driver.)
• timestamp.feature — timestamp formatting and accuracy. (Tagged @freertoswip: FreeRTOS example uses the RFC 5424 publication-date placeholder; needs a real RTC-backed clock callback.)
• prival.feature — facility / severity encoding. (Tagged @freertoswip: cmdline-args reason as above.)
• structured_data.feature — SD-element formatting. (Tagged @freertoswip: FreeRTOS example wires no meta SD — sequenceId, sysUpTime, language all absent.)
• origin.feature — origin SD parameters. (Tagged @freertoswip: no origin SD wired in the FreeRTOS example.)
• time_quality.feature — timeQuality SD. (Tagged @freertoswip: no timeQuality SD wired.)

Docs and header surface

• Platform/FreeRtos/Interface/SolidSyslogFreeRtosDatagram.h added. (S08.03 slice 1: SolidSyslogFreeRtosDatagram adapter (host-TDD) #299; SolidSyslogFreeRtosStaticResolver.h added alongside in S08.03 slice 3a: FreeRTOS static resolver #292.)
• CLAUDE.md "Public header audiences" — new row. (Rows for both SolidSyslogFreeRtosDatagram.h and SolidSyslogFreeRtosStaticResolver.h added.)

Out of scope

• Concurrent emission — covered by S08.04.
• Store-and-forward — covered by S08.05.
• TCP / TLS — covered by S08.06 / S08.07.

References

• Parent epic E08 E08: FreeRTOS example #10 — UDP scenario list under "Story decomposition" item 3.
• Existing UDP path: SolidSyslogUdpSender + SolidSyslogPosixDatagram (POSIX) — FreeRTOS gets a parallel SolidSyslogFreeRtosDatagram.
• Predecessor S08.02 — provides the CI plumbing this builds on.