demo4_cli_golang

Demo application containing a CLI solution in pure Golang and the application is a file filter CLI program for OS of your choice.

Specification

Overview

• Using systems programming language of your choice (Go / C / C++) write a file filter CLI program for OS of your choice. This filter should accept hot folder path and backup folder path, backing-up any file that is created or modified in the chosen folder.

Requirements

• create a copy of any file created or modified in the hot folder
• backup files should have the same name of the original file with .bak extension
• if the file name is prefixed with 'delete_' it should be immediately deleted from the hot folder and backup folder
• keep a log file of all action taken by your program (file created, altered, backedup or deleted)
• log file can be viewed/filtered by you CLI app.
• log file filters should accept filter by [date, filename regex]
• the application must keep/save it's state between reboots

Bonus

• if the file name is prefixed with 'delete_ISODATETIME_' it should be deleted at the specified time
• Use non-blocking IO

Codebase structure (hexagonal architecture)

./
├── LICENSE                 # Open-source license for the project
├── README.md               # Project documentation, setup, and usage instructions
├── Taskfile.yml            # Task automation file (for Windows/Linux/macOS)
├── Taskfile_windows.yml    # Task automation file (for Windows)
├── cmd                     # Entry point for the application (Application Layer)
|     ├── api
|       └── main.go         # Main entry point of the application, initializes dependencies
│   └── cmd.go              # CLI command definitions and execution logic
├── go.mod                  # Go module file (dependency management)
├── go.sum                  # Checksum of module dependencies
|── .env.dist               # Example environment variables configuration
└── internal                # Business logic and core application implementation
    ├── adapters            # Secondary (driven) adapters (Infrastructure Layer)
    │        └── cli
    │            └── cli_commands.go  # CLI commands implementation (user interaction)
    └── core                # Core application logic (Domain Layer)
        └── service
            ├── file_monitor.go      # File monitoring service (watching file system events)
            ├── file_monitor_test.go # Unit tests for file monitoring service
            └── log_service.go       # Service handling log management and filtering

Setup

Prerequisites

• Go SDK 1.23 or higher from https://golang.org/dl/
• Taskfile from https://taskfile.dev

Installation

1. Clone the repository:

   git clone
   

2. Install dependencies:

   go mod download
   

3. Run the application dynamic mode:

   • Menu driven CLI application

   go run cmd\api\main.go    
   

   Example output:

   CLI tool to monitor and backup files
   
   Usage:
   file-filter-cli [command]
   
   Available Commands:
   completion  Generate the autocompletion script for the specified shell
   help        Help about any command
   logs        View logs
   logs-filter Filter logs by date or filename
   monitor     Start monitoring the hot folder
   
   Flags:
   -h, --help   help for file-filter-cli
   
   Use "file-filter-cli [command] --help" for more information about a command.
   

   • monitor command to start monitoring the hot folder

   go run cmd\api\main.go monitor

   • logs command to view logs

   # help
   go run cmd\api\main.go logs --help
   
   # logs
   go run cmd\api\main.go logs
   
   # logs with custom application log file
   go run main.go logs --file custom_log.out

   • logs-filter command to filter logs by date or filename

   # help
   go run cmd\api\main.go logs-filter --help
   
   # logs-filter
   go run cmd\api\main.go logs-filter
   
   # logs-filter with custom application log file
   go run cmd\api\main.go logs-filter --file custom_log.out
   
   # logs-filter with custom application log file and filter by date
   go run cmd/api/main.go logs-filter "2025-02-09"
   go run cmd/api/main.go logs-filter "2025-02-09 21:11"
   
   # logs-filter log file and filter by severity level
   go run main.go logs-filter "ERROR" --file custom_log.out

Manual E2E Test

1. Run the application:

   task run
   

2. Open a new terminal and run the following command on WSL Linux terminal:

• Create a ingestion ./hot and egestion ./backup folders.

  mkdir ./hot
  mkdir ./backup   
  

• Within WSL Linux open both ./hot and ./backup folders to track the changes.

  # Use tmux to split the terminal
  tmux
  
  # Split the terminal vertically
    Ctrl+b %
  
  # Split the terminal horizontally
    Ctrl+b "
  
  # Track the changes in the hot folder
  watch -n 1 ls -ls ./hot
  
  # Track the changes in the backup folder
  watch -n 1 ls -ls ./backup
  
  # Track the changes in the log file
  tail -f ./demo4_cli_golang.out
  
  # Track changes in the serialized state file
  watch -n 1 cat ./demo4_cli_golang.state.json
  
  # Create a file in the hot folder
  echo test > ./hot/test1.txt
  echo test > ./hot/test2.txt
  echo test > ./hot/test3.txt
  echo test >> ./hot/test1.txt
  touch ./hot/delete_test1.txt
  mv ./hot/test2.txt ./hot/test22.txt
  mv ./hot/test3.txt ./hot/delete_test3.txt
  

  Example tmux session:

  Example application log: demo4_cli_golang.out

  Example serialized state file: demo4_cli_golang.state.json

Development Workflow

1. Use the following developer workflows in Taskfile

   task
   

   Example output:

   ==
   Tasks available for this infra Kube.
   
   task: Available tasks for this project:
   * build:compile:windows:        Compiling binary for the windows platform
   * build:test:all:               Running entire test suite [unit]
   * build:test:helper:unit:       Running unit test suite
   * default:                      List all commands defined.