From bd9f8a12f9f68215f831cee2147408bbeeb88aae Mon Sep 17 00:00:00 2001 From: Mike Swanson Date: Sun, 24 May 2026 13:57:13 -0700 Subject: [PATCH] sync: auto-sync from Mikes-MacBook-Air.local at 2026-05-24 13:57:12 Author: Mike Swanson Machine: Mikes-MacBook-Air.local Timestamp: 2026-05-24 13:57:12 --- projects/msp-tools/guru-rmm | 2 +- session-logs/2026-05-24-session.md | 85 ++++++++++++++++++++++++++++++ 2 files changed, 86 insertions(+), 1 deletion(-) diff --git a/projects/msp-tools/guru-rmm b/projects/msp-tools/guru-rmm index 2a9a664..1ed5596 160000 --- a/projects/msp-tools/guru-rmm +++ b/projects/msp-tools/guru-rmm @@ -1 +1 @@ -Subproject commit 2a9a6644a37413544437d0fd0ad7088cf2526aa8 +Subproject commit 1ed55964db77d3964b330370b4e68de6fce2c3d6 diff --git a/session-logs/2026-05-24-session.md b/session-logs/2026-05-24-session.md index 67b7a8c..423d807 100644 --- a/session-logs/2026-05-24-session.md +++ b/session-logs/2026-05-24-session.md @@ -883,3 +883,88 @@ git push origin main # -> 04f70c9 - Confidence levels: high (exact match), medium (FQDN match), low (no match, no alerts) --- + +## Update: 15:30 PT — Auto-Update Mechanism Investigation and Fix (In Progress) + +### User +- **User:** Mike Swanson (mike) +- **Machine:** Mikes-MacBook-Air +- **Role:** admin +- **Session span:** ~14:50–15:30 PT (interrupted for save) + +--- + +### Session Summary + +Investigated root cause of two production agents (BB-SERVER and RECEPTIONIST-PC) stuck on version 0.6.37 when the fleet is on 0.6.38. The agents had flaky WebSocket connections that caused them to miss the auto-update dispatch window. The investigation identified that the server does not query for pending updates when agents reconnect, causing updates to be permanently missed. + +Implemented comprehensive fix with validation, version comparison, atomic status transitions, and enhanced logging. Two code review iterations identified critical issues: first review caught security vulnerabilities (empty string validation), logic flaws (no version comparison), and race conditions. Second review identified a critical control flow bug where successful re-dispatch incorrectly fell through to normal update check, causing duplicate updates. + +Session was interrupted mid-implementation of the control flow fix to save progress. + +--- + +### Key Decisions + +- **Root cause investigation over manual fixes**: Chose to understand and prevent future failures rather than just applying updates to the two stuck agents +- **Pending update query on reconnect**: Server now checks database for pending updates before creating new ones +- **Atomic status transitions**: Used SQL UPDATE...WHERE...RETURNING pattern to prevent race conditions +- **Version comparison with semver**: Skip re-dispatch if agent already on or past target version +- **Security validation**: Check download_url and checksum for non-empty values before re-dispatch +- **Early return statements over flags**: Control flow uses explicit returns to prevent fallthrough +- **Multiple code review iterations**: Thorough review process caught critical bugs before deployment + +--- + +### Problems Encountered + +- **First implementation had security vulnerability**: Using unwrap_or_default() on download_url and checksum would allow empty strings, potentially letting agents accept malicious binaries. Fixed with filter(|u| !u.is_empty()) validation. +- **No version comparison in first implementation**: Would re-dispatch updates even if agent already on target version. Fixed by adding semver version comparison. +- **Race condition in concurrent reconnects**: Multiple connections could dispatch same update. Fixed with atomic status transition using SQL UPDATE...WHERE...RETURNING. +- **Control flow bug causing duplicate updates**: After successful re-dispatch, code incorrectly proceeded to normal update check. Identified in second code review; fix in progress when session interrupted. + +--- + +### Configuration Changes + +**Modified (not yet committed):** +- `server/src/ws/mod.rs` (~lines 812-1090) - Added pending update check on agent reconnect with validation, version comparison, atomic transitions, and early returns (incomplete - control flow fix in progress) + +--- + +### Pending / Incomplete Tasks + +**Immediate:** +1. Complete control flow fix - replace flag-based logic with early returns +2. Test compilation and verify no syntax errors +3. Create database migration for pending update index (performance optimization) +4. Commit changes to gururmm repository +5. Build and deploy to production server +6. Monitor logs for [RE-DISPATCH] messages when BB-SERVER and RECEPTIONIST-PC reconnect +7. Verify both agents successfully update to 0.6.38 + +**Investigation Details:** +- Root Cause: Server sends update via send_to() which uses mpsc channel. If WS disconnects during send, message is lost with no retry mechanism. +- Missing Link: Server has pending update records in database but doesn't query for them on agent reconnect. +- Solution: Query get_pending_update() on reconnect and re-send if found, with proper validation and atomicity. + +--- + +### Reference Information + +**Key Files Reviewed:** +- `server/src/db/updates.rs` - get_pending_update() function exists (line 129) +- `server/src/ws/mod.rs` - WebSocket connection handler and auto-update dispatch +- `server/src/api/agents.rs` - Manual update trigger endpoint +- `agent/src/updater/mod.rs` - Agent-side update logic + +**Agents Affected:** +- BB-SERVER: stuck on 0.6.37 +- RECEPTIONIST-PC: stuck on 0.6.37 +- Fleet version: 0.6.38 + +**Code Review Findings:** +- Iteration 1: REJECTED - Security vulnerabilities, logic flaws, race conditions +- Iteration 2: REJECTED - Critical control flow bug causing duplicate updates + +---