🔍 LogParser — C++ Log Analysis CLI Tool

A production-style command-line log analysis tool written in C++17. Parse, filter, and generate reports from log files — with colorized output, keyword search, and file export.

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🚀 Features

• ✅ Parse standard log formats (timestamped, simple)
• ✅ Filter by log level (DEBUG, INFO, WARNING, ERROR, CRITICAL)
• ✅ Filter by keyword, source/component, or time range
• ✅ Colorized terminal output by severity
• ✅ Summary report with level breakdown and bar chart
• ✅ Top recurring error messages
• ✅ Export filtered results to a file
• ✅ Google Test unit test suite
• ✅ CMake build system

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🏗️ Architecture

log-parser/
├── src/
│   ├── main.cpp          # CLI argument parsing & orchestration
│   ├── LogEntry.h/.cpp   # Log entry model + level enum
│   ├── LogParser.h/.cpp  # File reading & regex-based line parsing
│   ├── LogFilter.h/.cpp  # Filter by level, keyword, source, time
│   ├── LogReport.h/.cpp  # Colorized output, summary, export
│   └── Utils.h/.cpp      # ANSI colors, string helpers
├── tests/
│   └── test_parser.cpp   # Google Test suite (12 tests)
├── sample_logs/
│   └── app.log           # Sample log file for testing
└── CMakeLists.txt

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⚡ Quick Start

Prerequisites

• C++17 compiler (GCC 9+ or Clang 10+)
• CMake 3.14+

git clone https://github.com/CodesbyNeo/log-parser.git
cd log-parser

# Build
cmake -B build -DCMAKE_BUILD_TYPE=Release
cmake --build build

# Run with sample log
./build/logparser sample_logs/app.log

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📡 Usage

logparser <logfile> [options]

Options:
  --level   <LEVEL>    Filter: DEBUG, INFO, WARNING, ERROR, CRITICAL
  --keyword <TEXT>     Search keyword in messages
  --source  <SOURCE>   Filter by component/source
  --after   <TIME>     Show entries after timestamp (YYYY-MM-DD HH:MM:SS)
  --before  <TIME>     Show entries before timestamp
  --export  <FILE>     Export results to a file
  --summary            Show summary report only
  --no-color           Disable colorized output

Examples

# Show all logs
./logparser sample_logs/app.log

# Show only errors
./logparser sample_logs/app.log --level ERROR

# Search for database issues
./logparser sample_logs/app.log --keyword "connection" --level ERROR

# Show summary report
./logparser sample_logs/app.log --summary

# Export errors to file
./logparser sample_logs/app.log --level ERROR --export errors.log

# Filter by time range
./logparser sample_logs/app.log --after "2024-01-15 08:10:00"

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🧪 Running Tests

cmake -B build
cmake --build build
cd build && ctest --output-on-failure

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📊 Sample Output

Parsing: sample_logs/app.log
Parsed 30 entries (1 lines skipped)
------------------------------------------------------------
[ERROR   ] 2024-01-15 08:02:10  [database    ] Connection pool exhausted
[ERROR   ] 2024-01-15 08:02:11  [server      ] Failed to process request
[CRITICAL] 2024-01-15 08:02:45  [server      ] Service degraded

============================================================
  LOG ANALYSIS REPORT
============================================================
  Total entries parsed : 30

  Level Breakdown:
  CRITICAL : 2  ██
  ERROR    : 5  █████
  WARNING  : 4  ████
  INFO     : 11 ███████████
  DEBUG    : 8  ████████

  Top Error Messages:
  1. [2x] Connection pool exhausted. Max connections: 10
  2. [2x] NullPointerException in UserService.getProfile()
============================================================

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📄 License

MIT