fix: only copy last 1000 lines of mosquitto log file during diagnostic collection

Avoid copying the entire mosquitto.log file to prevent cases where the log file is large (e.g. when no log rotation is configured)

Signed-off-by: reubenmiller <[email protected]>

Author: reubenmiller

configuration/contrib/diag-plugins/07_mosquitto.sh

@@ -34,7 +34,11 @@ mosquitto_journal() {
 
 mosquitto_log() {
     if [ -f /var/log/mosquitto/mosquitto.log ]; then
-        cp /var/log/mosquitto/mosquitto.log "$OUTPUT_DIR"/
+        # avoid copying the full file as it could be very large if logrotate is not installed and configured
+        # but still log the details as it could be helpful to diagnose
+        echo "mosquitto log file details:" >&2
+        ls -l /var/log/mosquitto/mosquitto.log >&2 ||:
+        tail -n 1000 /var/log/mosquitto/mosquitto.log > "$OUTPUT_DIR"/mosquitto.log ||:
     else
         echo "mosquitto.log not found" >&2
     fi

tests/RobotFramework/tests/tedge/diag/predefined_plugins.robot

@@ -73,8 +73,11 @@ Test Tags           theme:troubleshooting    theme:cli    theme:plugins
     FOR    ${log_name}    IN    @{log_names}
         File Size Is Not Zero    ${log_name}
     END
+    ${log_line_count}=    Execute Command
+    ...    cmd=wc -l /results/test/07_mosquitto/mosquitto.log | awk '{print $1}'
+    ...    strip=${True}
+    Should Be True    int(${log_line_count}) <= 1000
     Execute Command    diff /var/log/mosquitto/mosquitto.log /results/test/07_mosquitto/mosquitto.log
-    Log Should Contain    mosquitto-journal.log    Starting mosquitto.service
 
 
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