From db34e6c37a78a74bf6092ea08ec15879dc82920f Mon Sep 17 00:00:00 2001
From: Selim Mustafaev <selim@fastmail.fm>
Date: Wed, 3 Jan 2024 22:42:04 +0300
Subject: [PATCH] Fixed parsing dhcp leases

---
 CMakeLists.txt                |  2 +-
 DataSources/DnsmasqSource.cpp | 23 ++++++++++++-----------
 DataSources/DnsmasqSource.h   |  9 +++++++++
 main.cpp                      |  1 +
 4 files changed, 23 insertions(+), 12 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 316c290..c5559ee 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,7 +1,7 @@
 cmake_minimum_required(VERSION 3.27)
 project(aliencat_exporter)
 
-set(CMAKE_CXX_STANDARD 20)
+set(CMAKE_CXX_STANDARD 23)
 
 find_package(prometheus-cpp CONFIG REQUIRED)
 
diff --git a/DataSources/DnsmasqSource.cpp b/DataSources/DnsmasqSource.cpp
index 8bbab75..561e6c4 100644
--- a/DataSources/DnsmasqSource.cpp
+++ b/DataSources/DnsmasqSource.cpp
@@ -6,6 +6,11 @@
 #include <exception>
 #include <sstream>
 #include <iostream>
+#include <ranges>
+#include <array>
+#include <algorithm>
+
+namespace views = std::ranges::views;
 
 DnsmasqSource::DnsmasqSource() {
     _leases.open("/var/lib/misc/dnsmasq.leases");
@@ -18,20 +23,16 @@ std::vector<prometheus::Labels> DnsmasqSource::readLeases() {
     _leases.clear();
     _leases.seekg(0);
 
-    std::string line, time, mac, ip, host, id;
-    std::stringstream ss;
+    std::string line;
     std::vector<prometheus::Labels> result;
+    auto labels = std::array{ "time", "mac", "ip", "host", "id" };
 
     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}
-        });
+        prometheus::Labels lineMap;
+        for(const auto [index, item]: std::views::split(line, ' ') | views::enumerate) {
+            lineMap[labels[index]] = std::string_view(item);
+        }
+        result.push_back(lineMap);
     }
 
     return result;
diff --git a/DataSources/DnsmasqSource.h b/DataSources/DnsmasqSource.h
index 9117114..d2fc87e 100644
--- a/DataSources/DnsmasqSource.h
+++ b/DataSources/DnsmasqSource.h
@@ -10,6 +10,15 @@
 #include <vector>
 
 class DnsmasqSource {
+public:
+    enum LeaseField: int {
+        EXPIRY_TIME = 0,
+        MAC         = 1,
+        IP          = 2,
+        HOST        = 3,
+        ID          = 4
+    };
+
 private:
     std::ifstream _leases;
 
diff --git a/main.cpp b/main.cpp
index 80d5450..9db103d 100644
--- a/main.cpp
+++ b/main.cpp
@@ -24,6 +24,7 @@ int main() {
         std::this_thread::sleep_for(std::chrono::seconds(1));
         for(const auto& leaseLabels: dnsmasq.readLeases()) {
             gouge.Add(leaseLabels).Set(1);
+            std::cout << "mac: " << leaseLabels.at("mac") << std::endl;
         }
     }