tailscale proxy: collect sanitized Telemt active IP list

Telemt's Prometheus endpoint exposes only active-IP counts, while its loopback control API includes both the address list and sensitive proxy links. Add a root systemd timer that enters the Telemt container network namespace, filters the API response in memory, and publishes only username/address rows through the Zabbix agent key telemt.active_ips.list.\n\nThe collector refreshes every 30 seconds, writes atomically with root:zabbix 0640 permissions, and leaves the control API unexposed. Document the host installation and recommend one-day Zabbix history because client IP addresses are sensitive operational data.
2026-07-27 10:57:25 +03:00
parent d40941dbde
commit 673d747abd
5 changed files with 102 additions and 0 deletions
@@ -0,0 +1,52 @@
+#!/usr/bin/bash
+set -euo pipefail
+
+container_name="ts-lan-telemt"
+output_dir="/var/lib/zabbix"
+json_target="${output_dir}/telemt-active-ips.json"
+text_target="${output_dir}/telemt-active-ips.txt"
+
+install -d -o root -g zabbix -m 0750 "${output_dir}"
+
+container_pid="$(docker inspect --format '{{.State.Pid}}' "${container_name}")"
+if [[ -z "${container_pid}" || "${container_pid}" == "0" ]]; then
+  exit 1
+fi
+
+json_tmp="$(mktemp "${output_dir}/.telemt-active-ips.json.XXXXXX")"
+text_tmp="$(mktemp "${output_dir}/.telemt-active-ips.txt.XXXXXX")"
+trap 'rm -f "${json_tmp}" "${text_tmp}"' EXIT
+
+# The API response also contains proxy links and secrets. Filter it in-memory
+# and persist only the username and current active IP address list.
+nsenter -t "${container_pid}" -n \
+  curl --fail --silent --show-error --max-time 5 \
+  http://127.0.0.1:9091/v1/users |
+  jq --compact-output '{
+    users: [
+      .data[]
+      | {
+          username,
+          active_unique_ips: (.active_unique_ips_list // [])
+        }
+    ]
+  }' > "${json_tmp}"
+
+{
+  active_count="$(jq '[.users[].active_unique_ips[]] | length' "${json_tmp}")"
+  printf 'Active IP addresses: %s\n' "${active_count}"
+  jq --raw-output '
+    [
+      .users[] as $user
+      | $user.active_unique_ips[]
+      | "\($user.username) | \(.)"
+    ]
+    | if length == 0 then ["No active IP addresses"] else . end
+    | .[]
+  ' "${json_tmp}"
+} > "${text_tmp}"
+
+chown root:zabbix "${json_tmp}" "${text_tmp}"
+chmod 0640 "${json_tmp}" "${text_tmp}"
+mv -f "${json_tmp}" "${json_target}"
+mv -f "${text_tmp}" "${text_target}"