Real-time monitoring system

Core Requirements of Real-Time Monitoring Systems

Real-time monitoring systems need to fulfill core functionalities such as high-frequency data updates, visual presentation, and anomaly alerts. These systems typically interface with various sensors, log files, or API interfaces to acquire data at frequencies ranging from seconds to milliseconds. For example, temperature sensors on an industrial production line may upload data 10 times per second, while a server monitoring system collects CPU load metrics every minute.

Data latency must be controlled within reasonable limits, generally requiring the time difference between data generation and dashboard display to not exceed 3 seconds. For financial trading systems, this requirement may be even stricter, needing to achieve within 500 milliseconds.

Advantages of ECharts in Real-Time Monitoring

ECharts, as an open-source JavaScript visualization library from Baidu, is particularly well-suited for building real-time monitoring interfaces. Its dynamic data update capability is implemented through the setOption method, enabling efficient chart refreshes without re-rendering the entire DOM structure. Compared to lower-level libraries like D3.js, ECharts offers a more concise API, with built-in components such as timelines and data zooming that can be directly applied to monitoring scenarios.

// Basic real-time line chart example
let chart = echarts.init(document.getElementById('main'));
let option = {
  xAxis: { type: 'time' },
  yAxis: { type: 'value' },
  series: [{
    data: [],
    type: 'line',
    smooth: true
  }]
};
chart.setOption(option);

// Simulate real-time data updates
setInterval(() => {
  let newData = {
    name: new Date(),
    value: [new Date(), Math.random() * 100]
  };
  option.series[0].data.push(newData);
  // Keep the most recent 100 data points
  if(option.series[0].data.length > 100) {
    option.series[0].data.shift();
  }
  chart.setOption(option);
}, 500);

Data Communication Solution Design

Real-time monitoring systems typically employ the following combination of communication solutions:

1. WebSocket: Used for high-frequency data transmission, establishing a full-duplex communication channel
2. Server-Sent Events (SSE): Suitable for server-side unidirectional push scenarios
3. Long Polling: The most compatible fallback solution

// WebSocket connection example
const socket = new WebSocket('wss://monitor.example.com/ws');

socket.onmessage = (event) => {
  const data = JSON.parse(event.data);
  updateDashboard(data);
};

function updateDashboard(payload) {
  // Handle different types of data updates
  switch(payload.type) {
    case 'cpu':
      cpuChart.setOption({
        series: [{ data: payload.values }]
      });
      break;
    case 'memory':
      memoryGauge.setOption({
        series: [{ data: [{ value: payload.usage }]}]
      });
  }
}

Performance Optimization Strategies

Special attention must be paid to rendering performance in large-data scenarios:

1. Data Sampling: Apply downsampling algorithms like LTTB (Largest-Triangle-Three-Buckets) to historical data
2. Rendering Control: Use throttle to limit update frequency
3. Web Worker: Move data processing off the main thread

// Using the LTTB algorithm for sampling
function downsample(data, threshold) {
  if (data.length <= threshold) return data;
  
  const sampled = [];
  const bucketSize = data.length / threshold;
  let a = 0;
  
  for (let i = 0; i < threshold; i++) {
    const bucketStart = Math.floor(i * bucketSize);
    const bucketEnd = Math.min(Math.floor((i + 1) * bucketSize), data.length - 1);
    
    let maxArea = -1;
    let selectedPoint;
    
    for (let j = bucketStart + 1; j < bucketEnd; j++) {
      const area = calculateTriangleArea(
        data[a], data[j], data[bucketEnd]
      );
      if (area > maxArea) {
        maxArea = area;
        selectedPoint = data[j];
      }
    }
    
    sampled.push(selectedPoint || data[bucketEnd]);
    a = bucketEnd;
  }
  
  return sampled;
}

Anomaly Detection and Alerts

Real-time monitoring systems require built-in intelligent detection algorithms:

1. Threshold Alerts: Static rule configurations
2. Dynamic Baselines: Automatically calculate reasonable ranges based on historical data
3. Machine Learning: Use algorithms like Isolation Forest to detect anomalies

// Dynamic baseline calculation example
function calculateBaseline(historyData) {
  const values = historyData.map(d => d.value);
  const mean = values.reduce((a,b) => a + b, 0) / values.length;
  const stdDev = Math.sqrt(
    values.reduce((sq, n) => sq + Math.pow(n - mean, 2), 0) / values.length
  );
  
  return {
    upper: mean + 3 * stdDev,
    lower: mean - 3 * stdDev,
    current: values[values.length - 1]
  };
}

// Alert determination
function checkAlert(baseline) {
  if (baseline.current > baseline.upper) {
    showAlert('Value exceeds upper threshold');
  } else if (baseline.current < baseline.lower) {
    showAlert('Value falls below lower threshold');
  }
}

Multi-View Collaborative Analysis

Complex systems require multi-chart coordination:

1. Use the connect method to establish chart relationships
2. Implement brush operations for cross-view filtering
3. Shared data state management

// Chart linkage example
const chart1 = echarts.init(document.getElementById('chart1'));
const chart2 = echarts.init(document.getElementById('chart2'));

// Establish linkage
echarts.connect([chart1, chart2]);

// Shared time range
chart1.on('dataZoom', (params) => {
  const option = chart1.getOption();
  const startValue = option.dataZoom[0].startValue;
  const endValue = option.dataZoom[0].endValue;
  
  chart2.dispatchAction({
    type: 'dataZoom',
    startValue: startValue,
    endValue: endValue
  });
});

Mobile Adaptation Solutions

Monitoring interfaces on mobile devices require special handling:

1. Responsive Layout: Use resize events to automatically adjust chart dimensions
2. Touch Optimization: Enable gesture zooming and panning
3. Performance Tuning: Reduce the number of rendered data points

// Responsive handling
window.addEventListener('resize', () => {
  chart.resize();
});

// Mobile configuration options
const mobileOptions = {
  dataZoom: [{
    type: 'inside',
    filterMode: 'filter',
    zoomOnMouseWheel: false,
    moveOnMouseMove: true
  }],
  tooltip: {
    position: function(pos, params, dom, rect, size) {
      return [pos[0], 10];
    }
  }
};

Data Persistence and Retrospection

Monitoring systems need to record historical data for post-analysis:

1. Frontend Local Storage: Use IndexedDB to store recent data
2. Screenshot Saving: Export chart states using getDataURL
3. Time Travel: Implement historical data playback functionality

// Using IndexedDB for data storage
const dbRequest = indexedDB.open('MonitorDB', 1);

dbRequest.onupgradeneeded = (event) => {
  const db = event.target.result;
  db.createObjectStore('metrics', { keyPath: 'timestamp' });
};

function saveData(timestamp, metric, value) {
  const transaction = db.transaction(['metrics'], 'readwrite');
  const store = transaction.objectStore('metrics');
  store.put({ timestamp, metric, value });
}

// Historical playback functionality
function playHistory(startTime, endTime) {
  const range = IDBKeyRange.bound(startTime, endTime);
  const request = store.getAll(range);
  
  request.onsuccess = (event) => {
    const data = event.target.result;
    animateData(data);
  };
}

Theme and Style Customization

Enterprise-grade monitoring systems often require branding customization:

1. Color Themes: Configure via the theme object
2. Dark Mode: Dynamically switch theme colors
3. Custom Components: Extend ECharts' native functionalities

// Custom theme
const customTheme = {
  color: ['#dd6b66','#759aa0','#e69d87','#8dc1a9'],
  backgroundColor: '#f5f5f5',
  textStyle: {
    fontFamily: 'Arial, sans-serif'
  }
};
echarts.registerTheme('corporate', customTheme);

// Dynamic dark mode switching
function toggleDarkMode() {
  const isDark = document.body.classList.toggle('dark-mode');
  chart.setOption({
    backgroundColor: isDark ? '#222' : '#fff',
    textStyle: { color: isDark ? '#eee' : '#333' }
  });
}

Security and Access Control

Production monitoring systems must consider:

1. Data Encryption: Use wss protocol for WebSocket
2. Access Control: Role-based view filtering
3. Operation Auditing: Record critical configuration changes

// Role-sensitive configuration
function setupRoleBasedView(userRole) {
  const options = {
    toolbox: {
      show: userRole === 'admin',
      feature: {
        saveAsImage: userRole === 'admin',
        dataView: userRole === 'analyst'
      }
    }
  };
  chart.setOption(options);
}

// Sensitive operation auditing
function logAction(action) {
  fetch('/api/audit', {
    method: 'POST',
    body: JSON.stringify({
      user: currentUser,
      action: action,
      timestamp: new Date()
    })
  });
}