neuron-tai/docs/issues/46-tracker-env-and-first-node-autojoin.md

US-046 — Tracker .env awareness + first-node auto-join bootstrap

Status: in progress Priority: High (blocks the US-044 two-machine test; auto-join dead on fresh trackers)

Context

Reported 2026-07-06: a node auto-joining a fresh tracker prints (auto-join unavailable: HTTP Error 503) and then cannot download the model from the tracker. Two independent causes:

1. Bootstrap chicken-and-egg. _handle_network_assign handles an empty registry by falling back to the first deployable recommended preset — but deployability is computed from the registered pool only (_deployment_summary(all_nodes, preset)), which is empty, so nothing is ever deployable and the first node always gets 503. The caller's own vram_mb / ram_mb (already sent in the query) are ignored.
2. Tracker ignores .env. meshnet-node loads .env (cwd) and ~/.config/meshnet/secrets.env at startup; meshnet-tracker does not. The repo .env sets MESHNET_DOWNLOAD_DIR=/run/media/popov/DATA/llm/safetensor/models, but the tracker only reads --models-dir / MESHNET_MODELS_DIR, so models_dir stays unset → /v1/model-files/download returns 404 "tracker model-file source is not enabled" and assignments carry no model_sources.
3. Symlink tars (found while verifying). HF cache snapshots are symlink farms into blobs/; both the tracker's /v1/model-files/download and the node's write_shard_archive tarred the symlinks themselves (tarfile default dereference=False), so receivers extracted dangling links instead of weights.

Fix

1. In the empty-registry branch of _handle_network_assign, synthesize a candidate _NodeEntry from the caller's vram_mb/ram_mb query params and include it in the pool used for the deployability gate (and the reported deployment summary), so a recommended preset that fits pool + caller bootstraps the network.
2. Tracker CLI loads env defaults the same way the node CLI does (.env in cwd, then ~/.config/meshnet/secrets.env, never overriding already-set env vars).
3. TrackerServer models-dir resolution falls back --models-dir → MESHNET_MODELS_DIR → MESHNET_DOWNLOAD_DIR (the node store and tracker source are the same directory on a box running both).
4. Archive with dereference=True in both tar writers so model file contents ship instead of snapshot symlinks.

Acceptance criteria

• Fresh tracker (empty registry) + caller with enough memory for a recommended preset → /v1/network/assign returns 200 with that preset, gap_found=true, and model_sources populated when the tracker holds a local snapshot. (Verified live: 128 GB caller got qwen3.6-35b-a3b 0–39 with tracker model_sources.)
• Fresh tracker + caller too small for any recommended preset → still 503. (Verified live with a 4 GB caller.)
• meshnet-tracker start in a directory with .env setting MESHNET_DOWNLOAD_DIR serves /v1/model-files/download from that dir with no extra flags. (Verified live; tar entries are regular files, not symlinks.)
• Explicit --models-dir and MESHNET_MODELS_DIR still take precedence, in that order.
• python -m pytest passes from repo root (two known env-dependent failures occur only while a live meshnet-node holds port 7000).