Improve Zabbix agent service detection

Use systemctl cat to reliably detect zabbix-agent2 or zabbix-agent units, add fallback when no agent is present, and warn instead of failing. Guard stop/start calls so they only run when an agent service was found, and use [[ ]] for safer string comparisons. Adjust package upgrade logic to handle both agent2 and agent cases accordingly.

ct/zabbix.sh

@@ -35,15 +35,18 @@ function update_script() {
     exit
   fi
 
-  if systemctl list-unit-files | grep -q zabbix-agent2.service; then
+  if systemctl cat zabbix-agent2.service &>/dev/null; then
     AGENT_SERVICE="zabbix-agent2"
-  else
+  elif systemctl cat zabbix-agent.service &>/dev/null; then
     AGENT_SERVICE="zabbix-agent"
+  else
+    AGENT_SERVICE=""
+    msg_warn "No Zabbix Agent service found, skipping agent actions"
   fi
 
   msg_info "Stopping Services"
   systemctl stop zabbix-server
-  systemctl stop "$AGENT_SERVICE"
+  [[ -n "$AGENT_SERVICE" ]] && systemctl stop "$AGENT_SERVICE"
   msg_ok "Stopped Services"
 
   read -rp "Choose Zabbix version [1] 7.0 LTS  [2] 7.4 (Latest Stable)  [3] Latest available (default: 2): " ZABBIX_CHOICE
@@ -83,13 +86,13 @@ function update_script() {
 
   $STD apt install --only-upgrade zabbix-server-pgsql zabbix-frontend-php php8.4-pgsql
 
-  if [ "$AGENT_SERVICE" = "zabbix-agent2" ]; then
+  if [[ "$AGENT_SERVICE" == "zabbix-agent2" ]]; then
     $STD apt install --only-upgrade zabbix-agent2 zabbix-agent2-plugin-postgresql
     if [ -f /etc/zabbix/zabbix_agent2.d/plugins.d/nvidia.conf ]; then
       sed -i 's|^Plugins.NVIDIA.System.Path=.*|# Plugins.NVIDIA.System.Path=/usr/libexec/zabbix/zabbix-agent2-plugin-nvidia-gpu|' \
         /etc/zabbix/zabbix_agent2.d/plugins.d/nvidia.conf
     fi
-  else
+  elif [[ "$AGENT_SERVICE" == "zabbix-agent" ]]; then
     $STD apt install --only-upgrade zabbix-agent
   fi
 
@@ -105,7 +108,7 @@ function update_script() {
 
   msg_info "Starting Services"
   systemctl start zabbix-server
-  systemctl start "$AGENT_SERVICE"
+  [[ -n "$AGENT_SERVICE" ]] && systemctl start "$AGENT_SERVICE"
   systemctl restart apache2
   msg_ok "Started Services"
   msg_ok "Updated successfully!"

misc/alpine-install.func

@@ -34,6 +34,42 @@ EOF
   fi
 }
 
+set -Eeuo pipefail
+trap 'error_handler $? $LINENO "$BASH_COMMAND"' ERR
+trap on_exit EXIT
+trap on_interrupt INT
+trap on_terminate TERM
+
+error_handler() {
+  local exit_code="$1"
+  local line_number="$2"
+  local command="$3"
+
+  if [[ "$exit_code" -eq 0 ]]; then
+    return 0
+  fi
+
+  printf "\e[?25h"
+  echo -e "\n${RD}[ERROR]${CL} in line ${RD}$line_number${CL}: exit code ${RD}$exit_code${CL}: while executing command ${YW}$command${CL}\n"
+  exit "$exit_code"
+}
+
+on_exit() {
+  local exit_code="$?"
+  [[ -n "${lockfile:-}" && -e "$lockfile" ]] && rm -f "$lockfile"
+  exit "$exit_code"
+}
+
+on_interrupt() {
+  echo -e "\n${RD}Interrupted by user (SIGINT)${CL}"
+  exit 130
+}
+
+on_terminate() {
+  echo -e "\n${RD}Terminated by signal (SIGTERM)${CL}"
+  exit 143
+}
+
 # This function sets up the Container OS by generating the locale, setting the timezone, and checking the network connection
 setting_up_container() {
   msg_info "Setting up Container OS"

misc/install.func

@@ -172,7 +172,7 @@ network_check() {
   fi
 
   set -e
-  trap 'error_handler' ERR
+  trap 'error_handler $LINENO "$BASH_COMMAND"' ERR
 }
 
 # ==============================================================================