logcenter

Centralized log collector for a node. Every yuno ships its log records to logcenter over UDP (the peer of the kernel’s to_udp log handler, default udp://127.0.0.1:1992). logcenter counts them by priority, writes them to size/disk-guarded rotatory files, aggregates a summary report, watches free disk/memory, and can e-mail the report or even restart the node on a queue alarm.

Architecture¶

C_LOGCENTER            <- counting, rotation, summary, monitoring, self-heal
    > C_GSS_UDP_S      <- UDP server (udp://127.0.0.1:1992), receives log records
    > C_TIMER          <- periodic disk/memory monitor

Summary e-mails are sent by publishing EV_SEND_EMAIL to the emailsender service (see emailsender).

Wire format¶

Each UDP datagram from the to_udp handler is:

<priority:1 char><sequence:8 hex><message bytes...><crc:8 hex>

logcenter verifies the trailing CRC, tracks the sequence (gaps are only logged under the debug trace), strips both, then files the message. If the message body is JSON ({...}) it is also folded into the summary tree.

What it does with each record¶

1. Counts it by syslog priority — Alert, Critical, Error, Warning, Info, Debug, Audit, Monitor.

2. Writes it to a rotatory log file under the yuno’s logs/ directory, named from log_filename (mask DD/MM/CCYY-W-ZZZ). Rotation is bounded by max_rotatoryfile_size and pauses when free disk drops below min_free_disk.

3. Aggregates JSON records into a summary grouped by msgset → msg → count (separately for errors, warnings, infos).

Configuration¶

Inspect the effective config at runtime with ycommand command-yuno id=<id> service=__yuno__ command=view-config.

Commands¶

The summary report (from display-summary / send-summary) looks like:

{
    "Global Counters": { "Alert": 0, "Critical": 0, "Error": 2, "Warning": 39, "Info": 1185, "Debug": 1937, "Audit": 0, "Monitor": 0 },
    "Node Owner": "artgins",
    "Global Errors":   { "App": { "email NOT sent": 1 }, "Liburing": { "getaddrinfo() FAILED": 1 } },
    "Global Warnings": { "Info": { "No authz db, authz only to local access": 1 } },
    "Global Infos":    { "Connect Disconnect": { "Connected": 295, "Disconnected": 386 } }
}

Monitoring & self-heal¶

• Resource watch: on its timer logcenter checks free disk and free RAM (each re-armed for 24 h after a check). When either falls to/below min_free_disk / min_free_mem it logs a warning and e-mails a report.

• Queue-alarm restart: when a record carries a queue_size field and restart_on_alarm is set with queue_size ≥ queue_restart_limit, it runs restart_yuneta_command via system(), throttled so a new restart cannot fire until timeout_restart_yuneta has elapsed. This is a last-resort watchdog for a node whose queues are runaway; it is off by default.

Debugging¶

Enable with ycommand command-yuno id=<id> service=__yuno__ command=set-gclass-trace gclass=C_LOGCENTER set=1 level=debug.