📘 C# Blog Series – Blog 44 **“C# Logging — NLog, Serilog, File Logging, Structured Logs कैसे Use करते हैं?

📘 C# Blog Series – Blog 44

**“C# Logging — NLog, Serilog, File Logging, Structured Logs कैसे Use करते हैं?

(Real-Life Example: GPS Packet Logs, Error Logs, Alert Logs, Debug Logs)”**

Real-world systems में Logging = Life है।
GPS Tracking Server, Payment System, ERP, API Backend —
अगर logging सही नहीं की तो:

• Errors trace नहीं होंगे

• Packets खो जाएंगे

• Server freeze का कारण पता नहीं चलेगा

• Debugging impossible

• Production में chaos

इस ब्लॉग में हम सीखेंगे:

✔ Basic File Logging
✔ Structured Logging
✔ Serilog
✔ NLog
✔ Log Levels
✔ Rolling Log Files
✔ GPS Server Logging Architecture

चलो सबसे आसान तरीके से शुरू करते हैं।

---

🟦 1. Logging क्या है? (Simple Definition)

Logging =
System में होने वाली हर महत्वपूर्ण activity का रिकॉर्ड रखना।

Examples:

• Packet received

• Packet parsing error

• Device connected

• DB failed

• Alert triggered

• Server crashed

GPS server में logging सबसे important element है।

---

🟢 2. Basic File Logging (Fast + Simple)

File.AppendAllText("logs.txt", $"{DateTime.Now} Packet: {pkt}\n");

सम्मानजनक काम करता है पर enterprise-grade नहीं है।

---

⭐ 3. Structured Logging (Production Standard)

Structured means → JSON format logs:

{
  "time": "2025-12-10",
  "imei": "861128068064267",
  "lat": 26.85,
  "lon": 80.94
}

Benefits:

✔ Searchable
✔ Machine-readable
✔ Perfect for dashboards
✔ Elastic, Kibana compatible

---

🌟 4. Introducing Serilog (BEST Logging Library)

Install:

dotnet add package Serilog.AspNetCore
dotnet add package Serilog.Sinks.File
dotnet add package Serilog.Sinks.Console

Setup:

Log.Logger = new LoggerConfiguration()
    .WriteTo.Console()
    .WriteTo.File("Logs/log_.txt", rollingInterval: RollingInterval.Day)
    .CreateLogger();

Log:

Log.Information("Packet received from {IMEI}", device.IMEI);
Log.Error(ex, "Packet failed");

Why Serilog?

✔ Structured logging
✔ Fast
✔ Amazing sinks (SQL, File, Console, Seq, Elastic)
✔ Perfect for GPS debugging

---

🟠 5. NLog — दूसरी सबसे famous logging library

Install:

dotnet add package NLog
dotnet add package NLog.Config
dotnet add package NLog.Targets

Config in nlog.config:

<targets>
  <target xsi:type="File" name="logfile" fileName="Logs/log.txt" />
</targets>
<rules>
  <logger name="*" minLevel="Info" writeTo="logfile" />
</rules>

Use:

logger.Info("Device connected: {IMEI}", imei);

---

🔵 6. Log Levels (Very Important)

Level	Use
Trace	हर छोटा detail (rare)
Debug	Development में
Information	Normal logs
Warning	Suspicious activity
Error	Recoverable error
Fatal	Crash-level errors

GPS server में:

• Packet logs → Information

• DB timeout → Warning

• Parsing failure → Error

• Server crash → Fatal

---

🟣 7. Real-Life GPS Logging Architecture

1. Packet Logs

Logs/Packets/packet_2025_12_10.log

Each line:

2025-12-10 14:22:10 | IMEI:861128068064267 | PKT:...,LAT:26.85,...

2. Error Logs

Logs/Errors/error_2025_12_10.log

3. Unknown Packet dumps

Logs/Dumps/unknown_2025_12_10.dump

4. Alert Logs

Logs/Alerts/[alert-type]/...

---

🔥 8. Real Code: Logging inside GPS Packet Processor

try
{
    parser.Parse(packet, device);
    Log.Information("Parsed packet for {IMEI}", device.IMEI);
}
catch(Exception ex)
{
    Log.Error(ex, "Packet parsing failed for {Packet}", packet);
    File.AppendAllText("Dumps/unknown.dump", packet + "\n");
}

Perfect production code.

---

🧠 9. Async Logging (Best for high-load servers)

Serilog automatically async बनाता है:

.WriteTo.Async(a => a.File("Logs/log.txt"))

GPS server में यह performance को 2x बढ़ा देता है।

---

📌 10. Rolling Logs (Daily logs auto-create)

Serilog:

.WriteTo.File("Logs/log_.txt", rollingInterval: RollingInterval.Day)

Automatic log splitting per day.

---

🛡 11. Avoid Overlogging (Common Mistake)

❌ हर packet को फ़ाइल में log करना (High load → HDD overload)
✔ Only errors or filtered packets log करो
✔ Packet dump छोटे batches में रखो

---

🔚 Conclusion

C# Logging आपके system को बनाता है:

✔ Traceable
✔ Debuggable
✔ Stable
✔ Crash-proof
✔ Production-ready
✔ GPS-optimized

GPS tracking server में logs का सही structure
आपके system को industry-level strong बनाता है।