5-th DL fix

docs/issues/47-model-source-download-visibility.md

@@ -1,4 +1,4 @@
-# US-047 — Model-source race: visibility, sane timeouts, quiet tracker aborts
+# US-047 — Tracker-first model downloads: visibility, sane timeouts, RAM-based sizing
 
 Status: in progress
 Priority: High (follow-up to US-044/US-046; blocks usable LAN downloads)
@@ -45,14 +45,40 @@ http://192.168.0.179:8080 --model Qwen3.6-35B-A3B`):
    `BrokenPipeError`/`ConnectionResetError` around the tar stream and log a
    single line instead of a traceback.
 
+## Design revision (2026-07-06, after live retest)
+
+The race is gone. User decision: **HuggingFace is used only when the model is
+not available from a tracker/peer source, or when `--tracker-source-disabled`
+is passed.** Sources are tried sequentially with progress + failure output;
+HF (layer-filtered via the source file list, else the remote index) is the
+fallback.
+
+Second live finding: the node was assigned only layers 0–2 of 40 on a 79 GB
+box. Cause: CPU-mode nodes still report the detected-but-unusable GPU's
+`vram_mb` (RTX 4060 → 8192), and shard sizing used VRAM whenever it was > 0
+(8 GB × 0.8 ≈ 6.5 GB ≈ 3 layers). Fixed on both sides: the node now sends
+`assignment_vram_mb` (0 unless CUDA is actually usable) to `/v1/nodes/assign`,
+and the tracker only trusts `vram_mb` when `device=cuda` (all three sizing
+sites), falling back to `ram_mb`.
+
 ## Acceptance criteria
 
-- [ ] Node started with an explicit `--model` never queries
+- [x] Node started with an explicit `--model` never queries
   `/v1/network/assign` and never prints `auto-join unavailable`.
-- [ ] During the race, tracker-source progress lines appear alongside HF
-  tqdm output; a failing tracker source prints its exception.
-- [ ] A ≥2 s read stall no longer aborts a tracker model-source download
+- [x] Tracker/peer model source is preferred outright; HF is contacted only
+  when no source is advertised, every source fails, or
+  `--tracker-source-disabled` is passed (flag on both CLI parsers, plumbed
+  through config and `run_startup`).
+- [x] Tracker-source downloads print progress every 512 MB and print the
+  exception + URL on failure; nothing fails silently.
+- [x] A ≥2 s read stall no longer aborts a tracker model-source download
   (30 s socket timeout).
-- [ ] Client disconnect during `/v1/model-files/download` logs one line on
+- [x] Client disconnect during `/v1/model-files/download` logs one line on
   the tracker, no traceback.
-- [ ] `python -m pytest` passes from repo root.
+- [x] CPU node with big RAM gets a RAM-sized shard: `/v1/nodes/assign` and
+  both `/v1/network/assign` sizing paths ignore VRAM unless `device=cuda`.
+- [x] `pytest tests/test_node_startup.py tests/test_tracker_routing.py`
+  passes (139/140; the one failure is the pre-existing port-dependent
+  `test_mining_cli` case, present on clean master).
+- [ ] Live two-machine retest: Windows node downloads only from tracker at
+  LAN speed and is assigned a RAM-sized shard.