From 1f0ebfaad729a6d79ed7824b8be7aabc1b43f224 Mon Sep 17 00:00:00 2001
From: Selim Mustafaev <smumustafaev@sberbank.ru>
Date: Tue, 2 Jan 2024 01:21:28 +0300
Subject: [PATCH] Adding dnsmasq leases file parser

---
 CMakeLists.txt                |  4 +++-
 DataSources/DnsmasqSource.cpp | 38 +++++++++++++++++++++++++++++++++++
 DataSources/DnsmasqSource.h   | 22 ++++++++++++++++++++
 main.cpp                      | 18 ++++++++++-------
 4 files changed, 74 insertions(+), 8 deletions(-)
 create mode 100644 DataSources/DnsmasqSource.cpp
 create mode 100644 DataSources/DnsmasqSource.h

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 508e39d..5f4785e 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,5 +5,7 @@ set(CMAKE_CXX_STANDARD 20)
 
 find_package(prometheus-cpp CONFIG REQUIRED)
 
-add_executable(aliencat_exporter main.cpp)
+add_executable(aliencat_exporter main.cpp
+        DataSources/DnsmasqSource.cpp
+        DataSources/DnsmasqSource.h)
 target_link_libraries(aliencat_exporter PRIVATE prometheus-cpp::pull)
diff --git a/DataSources/DnsmasqSource.cpp b/DataSources/DnsmasqSource.cpp
new file mode 100644
index 0000000..8bbab75
--- /dev/null
+++ b/DataSources/DnsmasqSource.cpp
@@ -0,0 +1,38 @@
+//
+// Created by Мустафаев Селим Мустафаевич on 01.01.2024.
+//
+
+#include "DnsmasqSource.h"
+#include <exception>
+#include <sstream>
+#include <iostream>
+
+DnsmasqSource::DnsmasqSource() {
+    _leases.open("/var/lib/misc/dnsmasq.leases");
+    if(_leases.fail()) {
+        throw std::runtime_error("failed to open leases file");
+    }
+}
+
+std::vector<prometheus::Labels> DnsmasqSource::readLeases() {
+    _leases.clear();
+    _leases.seekg(0);
+
+    std::string line, time, mac, ip, host, id;
+    std::stringstream ss;
+    std::vector<prometheus::Labels> result;
+
+    while(std::getline(_leases, line)) {
+        ss << line;
+        ss >> time >> mac >> ip >> host >> id;
+        result.push_back({
+            {"time", time},
+            {"mac", mac},
+            {"ip", ip},
+            {"host", host},
+            {"id", id}
+        });
+    }
+
+    return result;
+}
diff --git a/DataSources/DnsmasqSource.h b/DataSources/DnsmasqSource.h
new file mode 100644
index 0000000..9117114
--- /dev/null
+++ b/DataSources/DnsmasqSource.h
@@ -0,0 +1,22 @@
+//
+// Created by Мустафаев Селим Мустафаевич on 01.01.2024.
+//
+
+#ifndef ALIENCAT_EXPORTER_DNSMASQSOURCE_H
+#define ALIENCAT_EXPORTER_DNSMASQSOURCE_H
+
+#include <prometheus/counter.h>
+#include <fstream>
+#include <vector>
+
+class DnsmasqSource {
+private:
+    std::ifstream _leases;
+
+public:
+    DnsmasqSource();
+    std::vector<prometheus::Labels> readLeases();
+};
+
+
+#endif //ALIENCAT_EXPORTER_DNSMASQSOURCE_H
diff --git a/main.cpp b/main.cpp
index 63fb10e..80d5450 100644
--- a/main.cpp
+++ b/main.cpp
@@ -1,3 +1,5 @@
+#include "DataSources/DnsmasqSource.h"
+
 #include <iostream>
 #include <chrono>
 #include <thread>
@@ -7,20 +9,22 @@
 #include <prometheus/counter.h>
 
 int main() {
-    prometheus::Exposer exposer{"127.0.0.1:9000"};
-    prometheus::Registry registry;
+    prometheus::Exposer exposer{"0.0.0.0:9000"};
+    auto registry = std::make_shared<prometheus::Registry>();
+    DnsmasqSource dnsmasq;
 
     auto& gouge = prometheus::BuildGauge()
             .Name("aliencat_dnsmasq_leases")
-            .Register(registry);
+            .Help("Dnsmasq leases detail info")
+            .Register(*registry);
 
-    auto& counter = prometheus::BuildCounter()
-            .Name("aliencat_dnsmasq_leases")
-            .Register(registry);
+    exposer.RegisterCollectable(registry);
 
     for (;;) {
         std::this_thread::sleep_for(std::chrono::seconds(1));
-        gouge.Add({"mac", ""}).Set(0);
+        for(const auto& leaseLabels: dnsmasq.readLeases()) {
+            gouge.Add(leaseLabels).Set(1);
+        }
     }
 
     return 0;