nginx-log-analyzer/index.js

Nginx Log Analyzer

#!/usr/bin/env node

const fs = require("fs");
const readline = require("readline");
const chalk = require("chalk");
const uaParser = require("ua-parser-js");

// Function to analyze the log file
async function analyzeLogFile(filePath) {
  const logData = {
    totalRequests: 0,
    statusCodes: {},
    referrers: {},
    urls: {},
    browsers: {},
  };

  try {
    const fileStream = fs.createReadStream(filePath);
    const rl = readline.createInterface({
      input: fileStream,
      crlfDelay: Infinity,
    });

    console.log(chalk.blue("Reading log file..."));

    // Process each line of the log file
    for await (const line of rl) {
      // Extract relevant data from the log line
      const logParts = line.match(/"([^"]*)"|(\S+)/g);
      if (!logParts || logParts.length < 10) continue; // Skip malformed or empty lines

      logData.totalRequests += 1; // Count only valid lines

      const method = logParts[5]?.replace(/"/g, "").split(" ")[0];
      const url = logParts[5]?.replace(/"/g, "").split(" ")[1];
      const statusCode = logParts[6];
      const referrer = logParts[8];
      const userAgent = logParts[9]?.replace(/"/g, "");

      // Count HTTP status codes
      if (statusCode) {
        logData.statusCodes[statusCode] =
          (logData.statusCodes[statusCode] || 0) + 1;
      }

      if (referrer) {
        logData.referrers[referrer] = (logData.referrers[referrer] || 0) + 1;
      }

      // Count accessed URLs
      if (url) {
        logData.urls[url] = (logData.urls[url] || 0) + 1;
      }

      // Parse User-Agent and count browsers
      if (userAgent) {
        const parsedUA = uaParser(userAgent);
        const browserName = parsedUA.browser.name || "Unknown";
        logData.browsers[browserName] = (logData.browsers[browserName] || 0) + 1;
      }
    }

    console.log(chalk.green("Log analysis completed!"));
    return logData;
  } catch (error) {
    console.error(chalk.red(`Error: ${error.message}`));
    return null;
  }
}

// Function to print analysis results
function printAnalysisResults(logData) {
  if (!logData) {
    console.log(chalk.red("Log analysis failed."));
    return;
  }

  console.log(chalk.yellow("\n--- Log Analysis Results ---\n"));
  console.log(chalk.green(`Total Requests: ${logData.totalRequests}`));

  console.log(chalk.grey("\nReferrers:"));
  for (const [status, count] of Object.entries(logData.referrers).sort(
    (a, b) => b[1] - a[1]
  )) {
    const percentage = ((count / logData.totalRequests) * 100).toFixed(2);
    console.log(`  ${status}: ${count} (${percentage}%)`);
  }

  console.log(chalk.blue("\nHTTP Status Codes:"));
  for (const [status, count] of Object.entries(logData.statusCodes).sort(
    (a, b) => b[1] - a[1]
  )) {
    const percentage = ((count / logData.totalRequests) * 100).toFixed(2);
    console.log(`  ${status}: ${count} (${percentage}%)`);
  }

  console.log(chalk.magenta("\nMost Frequently Accessed PATHs:"));
  const sortedUrls = Object.entries(logData.urls).sort((a, b) => b[1] - a[1]);
  sortedUrls.slice(0, 10).forEach(([url, count]) => {
    const percentage = ((count / logData.totalRequests) * 100).toFixed(2);
    console.log(`  ${url}: ${count} (${percentage}%)`);
  });

  console.log(chalk.cyan("\nTop Browsers:"));
  const sortedBrowsers = Object.entries(logData.browsers).sort(
    (a, b) => b[1] - a[1]
  );
  sortedBrowsers.slice(0, 5).forEach(([browser, count]) => {
    const percentage = ((count / logData.totalRequests) * 100).toFixed(2);
    console.log(`  ${browser}: ${count} (${percentage}%)`);
  });
}

// Read file path from command-line arguments and analyze the log
const logFilePath = process.argv[2];

if (!logFilePath) {
  console.log(chalk.red("Log file parameter is required."));
  process.exit();
}

analyzeLogFile(logFilePath).then(printAnalysisResults);