fix(librenms): treat WORSE, BETTER and CHANGED as open alert states in get_state()

LibreNMS encodes the alert lifecycle in alerts.state with six
values (CLEAR, ACTIVE, ACKNOWLEDGED, WORSE, BETTER, CHANGED).
Only ACTIVE was mapped to WARN/CRIT, so open alerts in the
transitional states 3/4/5 were silently reported as OK. Also
accept 3, 4 and 5, matching the LibreNMS "notifiable alert"
definition used by the alerter itself.

Author: markuslf

CHANGELOG.md

@@ -8,7 +8,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
-tbd
+### Fixed
+
+* librenms.py: `get_state()` now also maps the LibreNMS alert states `WORSE` (3), `BETTER` (4) and `CHANGED` (5) to WARN/CRIT. Previously only `ACTIVE` (1) was treated as an alerting state, so open alerts in any of those three states were silently reported as OK. `WORSE` and `BETTER` exist in LibreNMS since 1.54 (July 2019); `CHANGED` was added in LibreNMS 25.2.0 (February 2025) and is now triggered whenever the alert `diff` detects a change
 
 
 ## [v3.4.0] - 2026-04-22

librenms.py

@@ -12,7 +12,7 @@
 needed by LibreNMS check plugins."""
 
 __author__ = 'Linuxfabrik GmbH, Zurich/Switzerland'
-__version__ = '2025042001'
+__version__ = '2026042401'
 
 from . import (
     base,  # pylint: disable=C0413
@@ -124,12 +124,17 @@ def get_state(librestate, severity='crit'):
     """
     Translate LibreNMS service state to a Nagios-compatible state.
 
-    LibreNMS returns a custom service state where:
-      - 0 = OK
-      - 1 = Alert
-      - 2 = Acknowledged
+    LibreNMS encodes the alert lifecycle in `alerts.state` (see
+    `LibreNMS/Enum/AlertState.php`):
+      - 0 = CLEAR / RECOVERED
+      - 1 = ACTIVE
+      - 2 = ACKNOWLEDGED
+      - 3 = WORSE
+      - 4 = BETTER
+      - 5 = CHANGED
 
-    This function maps these LibreNMS states to Nagios exit codes.
+    ACTIVE, WORSE, BETTER and CHANGED all represent an open, notifiable
+    alert, so they map to WARN/CRIT. ACKNOWLEDGED and CLEAR map to OK.
 
     ### Parameters
     - **librestate** (`int`):
@@ -154,8 +159,10 @@ def get_state(librestate, severity='crit'):
     1
     >>> get_state(1, severity='crit')
     2
+    >>> get_state(3, severity='crit')
+    2
     """
 
-    if librestate != 1:
+    if librestate not in (1, 3, 4, 5):
         return STATE_OK
     return STATE_CRIT if severity == 'crit' else STATE_WARN