feat(serve): opt-in etcd-lease presence for the daemon's live sessions#487
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The mu-daemon slice of lease-backed dialogue presence (push-mailbox spec §1; completes the trio: mu#482 server read side, agent_tools#48 cc watch holder). One lease per daemon + one reconciliation task: every TTL/3 it keepalives and syncs /mu/dialogue/v1/peers/ against the LIVE session registry (mu:<daemon_id>:<session_id> per session + a daemon key) — no lifecycle hooks, so every create/remove path (workers included) is covered on the next tick, and a crashed daemon's keys vanish with its single lease. Rehydrated read-only ghosts are excluded via a new Sessions::live_session_ids() (inner + workers only). Strictly opt-in per operator requirement (adopting mu must not require etcd): spawned only when events_dir is set (production; same hermeticity posture as the supervisor mailbox) AND [dialogue.presence] enabled=true is present in the config mu-core carries opaquely (mu#485). No cargo feature: reqwest is already in the dep tree via rmcp's reqwest transport and base64 is a workspace dep, so the compile-cost delta is nil — config-gating alone keeps the adoption barrier flat. Fail-open: etcd trouble degrades to activity-derived presence and retries; sessions are never affected. Verified live against etcd 3.6.5 + the production dialogue server: mu serve start -> daemon peer visible as presence=lease on the channel; kill -> liveness claim dropped at lease expiry.
sahuagin
approved these changes
Jul 13, 2026
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What
The mu-daemon slice of lease-backed dialogue presence — completes the trio (mu#482 server read side, agent_tools#48 cc watch holder):
mu serveregisters its live sessions (mu:<daemon_id>:<session_id>) plus a daemon key under one etcd lease, so mu peers show uppresence:"lease"on the dialogue channel and are addressable by broadcast without ever saying/polling. Crash → the single lease expires → all the daemon's keys vanish. The lease IS the liveness proof.Design: a reconciliation task (every TTL/3: keepalive + diff the keyspace against
Sessions::live_session_ids(), a new accessor coveringinner+workersand deliberately excluding rehydrated read-only ghosts) — no per-lifecycle hooks, so every create/remove path including spawned workers is covered on the next tick.Adoption barrier (operator requirement)
Strictly opt-in, no cargo feature needed:
events_diris set (production; same hermeticity posture as the supervisor mailbox — tests spawn nothing) and[dialogue.presence] enabled = trueis in the config (carried opaquely by mu-core since fix(mu-core): tolerate the [dialogue] config section owned by mu-dialogue #485).Testing
just cigreen.mu servestart → daemon peer visible aspresence:"lease"viaagent dialogue peers; kill → liveness claim dropped at lease expiry.🤖 Generated with Claude Code
https://claude.ai/code/session_019YY9xpjK6mWLJDMaYnvC6T