Peers discovered over mDNS could still attribute later library sync traffic to
temporary QUIC source ports. In a real GUI LAN run this made Host B try to
push its library to Host A's outbound port instead of Host A's advertised
listener, so Host A discovered the peer but never saw its games.
Carry the stable listener address in Hello and HelloAck, and key library sync
messages by peer_id instead of inferring identity from the transport source
address. The handshake path now explicitly refreshes an empty peer library from
the known listener address, matching the reliability of the direct-connect CLI
path without overwriting richer snapshot state when it already arrived.
This changes the current wire protocol, so PROTOCOL_VERSION is bumped to 3 and
all peers must be rebuilt together. The architecture note now documents that
listener addresses come from mDNS or Hello/HelloAck, never from ephemeral QUIC
source ports.
Test Plan:
- just fmt
- just test
- just clippy
- just build
- git diff --check
Refs: Local Linux/Win11 GUI LAN test logs from 2026-05-18.
The peer runtime previously accepted an `enable_mdns: bool` flag, plumbed
through `PeerStartOptions`, `spawn_peer_runtime`, `run_peer`, `Ctx`, and
`PeerCtx`. The lanspread-peer-cli harness exposed the toggle as
`--no-mdns` so test scenarios could fall back to explicit `connect`
commands when mDNS could not be relied on, in particular when multiple
peers ran inside `--network host` containers and could not advertise
independently.
That host-networking workaround no longer exists: the previous commit
moves harness containers onto a macvlan network, where each peer is a
real LAN device and mDNS just works between them. There is no scenario
left in the codebase where disabling mDNS is desirable. Per the project's
protocol policy in CLAUDE.md ("there is only one wire version, no
compatibility shims, no fallback paths"), an opt-out path with no current
caller is exactly the kind of dead code we should not carry.
Remove the flag and every plumbing point that exists only to support it:
- `PeerStartOptions::enable_mdns` and the custom `Default` impl that set
it to `true`; the struct now derives `Default` and just carries
`state_dir`.
- The `enable_mdns` parameter on `start_peer_with_options`,
`spawn_peer_runtime`, `run_peer`, and `Ctx::new`.
- The `enable_mdns` fields on `Ctx` and `PeerCtx` and the propagation
through `to_peer_ctx`.
- The `if ctx.enable_mdns` guard in `spawn_startup_services`;
`spawn_peer_discovery_service` is now always spawned.
- The `if ctx.enable_mdns { ... } else { ... }` branch in
`run_server_component`: the mDNS advertiser and event monitor are now
unconditionally started, and the no-mDNS-fallback log line that read
"mDNS disabled; direct peer address is ..." is gone. The
`direct_connect_addr` helper is kept because the mDNS-on branch still
uses it as a fallback when `local_peer_addr` has not yet been
populated.
- The internal test helpers in `handlers.rs`, `services/local_monitor.rs`,
and `services/stream.rs` that passed `true` as the trailing
`enable_mdns` arg to `Ctx::new`.
- In `lanspread-peer-cli`: the `--no-mdns` arg parsing, the
`Args::enable_mdns` field, the `mdns` key on the `cli-started` event
payload, and the `--no-mdns` mention in the help text and the crate
README.
The `Args::name` field is wired to the harness identity but is otherwise
untouched. The macvlan network created by `just peer-cli-net` is the
runtime prerequisite for this change to be observable across containers;
on a single workstation, two harness binaries on `127.0.0.1` discover
each other through mDNS on the loopback interface as before.
Test Plan:
- `just fmt`
- `just clippy`
- `just test`
- `just peer-cli-build`
- Two peers on macvlan: `just peer-cli-run alpha` and
`just peer-cli-run beta`; check that each emits `peer-discovered` and
`peer-connected` events without an explicit `connect` JSONL command.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
The follow-up backlog had drifted into three settled peer/runtime issues: the
legacy game-list fallback contradicted the one-wire-version policy, the Tauri
shell still re-derived local install state from disk after peer snapshots, and
`Availability::Downloading` existed even though active operations are already
reported through a separate operation table.
Remove the legacy `AnnounceGames` request and fallback service. Discovery now
ignores peers that do not advertise the current protocol and a peer id, and
library changes are sent through the current delta path only. This keeps the
runtime aligned with the documented current-build-only interoperability model.
Make peer `LocalGamesUpdated` snapshots authoritative for local fields in the
Tauri database. The GUI-side catalog still owns static metadata such as names,
sizes, and descriptions, but downloaded, installed, local version, and
availability now come from the peer runtime instead of a second whole-library
filesystem scan. Snapshot reconciliation also pins the missing-begin and
missing-finish lifecycle cases in tests.
Collapse availability back to the settled `Ready` and `LocalOnly` states.
Aggregation now counts only `Ready` peers as download sources, and the frontend
no longer carries a dead `Downloading` enum value.
The core peer also exposes the small non-GUI hooks needed by scripted callers:
startup options for state and mDNS, a local-ready event, direct connection, peer
snapshots, and an explicit post-download install policy. Those hooks reuse the
same current protocol path and do not add compatibility shims.
Test Plan:
- `git diff --check`
- `just fmt`
- `just clippy`
- `just test`
Refs: BACKLOG.md, FINDINGS.md, IMPL_DECISIONS.md
FINDINGS.md identified three merge blockers in the post-plan install/update
flow.
Updates now use FetchLatestFromPeers so the Tauri update command bypasses
local manifest serving and asks peers that advertise the latest version for
fresh file metadata. PeerGameDB now aggregates and validates file descriptions
from latest-version peers, keeping stale cached metadata for older versions
from poisoning chunk planning when filenames stay the same but sizes change.
Download-to-install handoff now performs explicit async state transitions.
The download task mutates Downloading to Installing or Updating under the
active-operation write lock, clears the cancellation token, and then runs the
install transaction. OperationGuard remains armed only as crash or abort
cleanup and is disarmed after normal explicit cleanup, so final refreshes no
longer race a deferred Drop cleanup.
Local library index writers now serialize the load/mutate/save window with one
async mutex. The index fingerprint also includes the root version.ini contents
so a same-length version rewrite in the same mtime second still updates the
reported local version.
The tradeoff is that local index mutations are serialized in-process instead
of moved into a dedicated actor. That keeps the fix small and scoped to the
merge blockers while preserving the existing scanner API.
Test Plan:
- just fmt
- just test
- just clippy
- just build
- git diff --check
Refs:
- FINDINGS.md
Move the repeated test TempDir implementations into a single peer
test_support module. The shared helper keeps the existing automatic cleanup
behavior and uses an atomic suffix plus timestamp so parallel tests do not
collide on the same path.
This is intentionally limited to test hygiene. It does not change the
availability model, split download.rs, or touch production scan/install
behavior beyond importing the shared helper from test modules.
Test Plan:
- git diff --check
- just fmt
- just clippy
- just test
Follow-up-Plan: FOLLOW_UP_2.md
Local operation spinners were driven by begin, finish, and failure event
history. If one of those lifecycle events was missed, the Tauri bridge could
keep a stale active operation and the React state would keep showing an
in-progress spinner until restart.
Peer local scan updates now carry an authoritative active-operation snapshot.
The peer still suppresses active game roots from peer-facing library deltas,
but it emits LocalGamesUpdated to the UI even when no library delta changed so
the snapshot can clear stale state after rollback or completion. The Tauri
bridge replaces its active-operation map from that snapshot, emits it with the
games-list payload, and the React merge uses it to restore download, install,
update, and uninstall spinners from current peer state rather than event
history alone.
This also enables the Tauri lib unit-test target so the reconciliation helper
can stay covered by the workspace test recipe.
Test Plan:
- git diff --check
- just fmt
- just clippy
- just test
Follow-up-Plan: FOLLOW_UP_2.md
The follow-up review found a few stale lifecycle edges around local game
transactions. Recovery could sweep active roots, post-operation refreshes
still re-ran full startup recovery, and the UI kept inferring local-only state
from downloaded and installed flags instead of the backend availability.
This updates the peer lifecycle so startup recovery skips active operations,
install/update/uninstall refresh only the affected game after the operation
guard is dropped, and path-changing game-directory updates are rejected while
operations are active. It also removes the dead UpdateGame command, drops the
unused manifest_hash write field while preserving old JSON reads, renames the
internal install-finished event, and carries availability through the DB,
peer summaries, Tauri refreshes, and the React model.
The included follow-up documents record the review source, implementation
decisions, and the remaining FOLLOW_UP_2.md work so later commits can stay
small instead of reopening the completed plan items.
Test Plan:
- git diff --check
- just fmt
- just clippy
- just test
Follow-up-Plan: FOLLOW_UP_PLAN.md
Implement the peer-owned state model from PLAN.md. A root-level version.ini
is now the download completion sentinel, local/ as a directory is the install
predicate, and exact root-level version.ini detection prevents nested files
from becoming sentinels by accident.
Add the peer operation table that gates downloads, installs, updates, and
uninstalls by game ID. Serving paths now reject non-catalog games, active
operations, missing sentinels, and any request that points under local/.
Remote aggregation treats LocalOnly peers as non-downloadable so they do not
contribute peer counts, candidate source selection, or latest-version checks.
Move install-side filesystem mutation into lanspread-peer::install. The new
module writes atomic .lanspread.json intents, uses .local.installing and
.local.backup with .lanspread_owned markers, and performs startup recovery
from recorded intent plus filesystem state. Downloads now buffer version.ini
chunks in memory and commit the sentinel last through .version.ini.tmp.
Replace the fixed 15-second monitor with notify-backed non-recursive watches,
per-ID rescan gating, and a 300-second fallback scan. The optimized rescan
path updates one cached library-index entry and active operation IDs preserve
their previous summary during scans.
Test Plan:
- just fmt
- just clippy
- just test
- just build
Refs: PLAN.md
Replace the detached tokio::spawn pattern in the peer runtime with a
supervised model built on tokio_util's CancellationToken and TaskTracker.
Long-lived services and child tasks now have an explicit parent, a
cancellation path, and a join point. Tauri can request a clean shutdown
on app exit instead of leaking work into process termination.
Background
~~~~~~~~~~
start_peer() previously returned only a command sender. The four startup
services (QUIC server, mDNS discovery, peer liveness, local library
monitor) and their child tasks (ping workers, handshake jobs, download
workers, announcement fan-outs, connection/stream handlers) were spawned
with raw tokio::spawn and detached. Closing the command channel sent
Goodbye notifications but did not stop those services. The mDNS blocking
worker had no cancellation path at all. Active downloads were stored as
JoinHandle<()> and force-aborted, which could interrupt file writes
mid-chunk.
Supervisor
~~~~~~~~~~
The runtime now owns a CancellationToken and a TaskTracker, threaded
through Ctx and PeerCtx. Each long-lived service is spawned through a
small supervisor (spawn_supervised_service) that wraps the service in
catch_unwind and enforces an explicit SupervisionPolicy:
QuicServer: Required (fatal; cancels the runtime if it dies)
Discovery: Restart(5s) (matches the prior self-restart loop)
Liveness: Restart(5s)
LocalMonitor: BestEffort (logs and exits, no restart)
A Required failure emits a new RuntimeFailed { component, error } event
to the UI and cancels the runtime; the command loop and goodbye
notifications still run to completion. The Tauri layer forwards the
event as "peer-runtime-failed" so a future UI can surface it.
mDNS cancellation
~~~~~~~~~~~~~~~~~
MdnsBrowser previously blocked on receiver.recv() forever. It now
exposes next_service_timeout(Duration) returning an MdnsServicePoll
enum (Service/Timeout/Closed) via recv_timeout(). The discovery worker
polls at 250ms and checks the shutdown flag between ticks, so
cancellation reaches the blocking thread within one poll interval
instead of waiting for the next mDNS event.
Downloads
~~~~~~~~~
active_downloads is now HashMap<String, CancellationToken>. Each
download gets a child token of the runtime shutdown, checked at chunk
and peer-attempt boundaries (never inside file writes). When all peers
with a game disappear, liveness cancels the token and emits
DownloadGameFilesAllPeersGone; the download exits Ok(()) without
emitting a duplicate Failed event.
DownloadStateGuard (context.rs) is held inside the download task and
clears downloading_games + active_downloads on Drop, covering the happy
path, error returns, cancellation, and task abort. Drop falls back to
spawning the cleanup if write-lock contention prevents try_write.
Public API and Tauri integration
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
start_peer() now returns PeerRuntimeHandle exposing:
fn sender(&self) -> UnboundedSender<PeerCommand>
fn shutdown(&self)
async fn wait_stopped(&mut self)
The Tauri layer stores the handle in managed state and switches its
main loop from .run(ctx) to .build(ctx).run(|h, e| ...). On
RunEvent::Exit it calls handle.shutdown() and blocks up to 2s on
wait_stopped(), giving services time to cancel and Goodbye packets time
to flush over a healthy LAN while staying short enough not to delay
process exit noticeably on a dead network.
The command loop distinguishes graceful shutdown from unexpected
channel closure: if recv() returns None and shutdown.is_cancelled() is
set, the loop returns Ok(()) silently. Only an unexpected close (no
cancellation observed) still emits RuntimeFailed. This avoids a
spurious failure event on every normal app close.
User-visible behavior changes
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
- Closing the app no longer leaks services into process termination;
Goodbye notifications are reliably attempted before exit.
- Downloads cancel cleanly (between chunks) instead of force-aborting
mid-write.
- A new "peer-runtime-failed" Tauri event fires when a Required service
cannot recover. No frontend handler exists yet — that is a follow-up.
Tradeoffs
~~~~~~~~~
- Workspace tokio-util now requires the "rt" feature for TaskTracker.
- The mDNS worker still runs in spawn_blocking and may stay parked
briefly between 250ms polls — acceptable for a desktop app.
- The 2s shutdown timeout on app exit is a deliberate compromise.
Tests
~~~~~
New unit tests:
- DownloadStateGuard clears tracking on completion, cancellation, and
parent-task abort (context.rs).
- Required failure cancels the runtime and emits RuntimeFailed
(startup.rs).
- Restart policy restarts until shutdown is requested (startup.rs).
- PeerRuntimeHandle.shutdown() observable via wait_stopped()
(startup.rs).
- Peers-gone cancellation emits only PeersGone, no duplicate Failed
(services/liveness.rs).
Test plan
~~~~~~~~~
cargo test --workspace
cargo clippy --workspace --all-targets
Manual smoke test on two peers on the same LAN:
1. Start a download, verify chunks transfer.
2. Close the receiving app mid-download — verify the sending peer
logs a Goodbye, not a connection-reset error.
3. Stop the sending peer mid-download — verify the receiver emits
DownloadGameFilesAllPeersGone, not Failed.
Follow-ups
~~~~~~~~~~
- Frontend handler for "peer-runtime-failed".
- Consider exposing the runtime handle's stopped watch to the frontend
for a reconnecting indicator on Required failures.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Peer startup used to bootstrap itself by spawning the runtime and immediately
sending a SetGameDir command back through its own control channel. The Tauri
integration then polled shared state until a directory appeared and waited two
seconds before asking peers for games. That made startup ordering implicit and
left a race-prone sleep in the UI bridge.
Install the initial game directory directly into the peer context instead. The
runtime now attempts the initial local-library scan before starting discovery,
then launches the server, discovery, liveness, and local monitor services from
that initialized context. Later directory changes still use SetGameDir, so the
existing UI command surface stays intact.
Use PathBuf and Path references across peer filesystem boundaries so directory
state is represented as a path rather than an optional string. The Tauri layer
now validates a selected game directory before storing it, loads the bundled
catalog on first use, and starts or updates the peer runtime from one helper.
Peer event fan-out is split into named handlers so the Tauri setup closure only
wires state and starts the event loop.
Shutdown goodbye notifications are still best-effort, but they are now awaited
with a short timeout instead of being spawned and forgotten. The tradeoff is a
small bounded wait during peer runtime shutdown in exchange for clearer task
ownership.
Test Plan:
- cargo test -p lanspread-peer
- cargo clippy
- cargo clippy --benches
- cargo clippy --tests
- cargo +nightly fmt
- git diff --check
Refs: none
ddidderr
