Stage 1

Write a library that performs statistics and aggregations for file metadata provided to it.

Required Functions

The library MUST implement the following functions:

AddFile(metadata FileMetadata) error

The function receives a structure containing the metadata of one file. This file should be taken into account when calculating statistics. The function can return an error if the input is invalid or processing of the file fails.

GetStats() FileStats

This function returns statistics for all files added until that point. The following statistics should be returned:

Number of files received
Largest file received (including name and size)
Average file size
Most frequent file extension (including number of occurences)
Percentage of text files of all files received
List of latest 10 file paths received

Required Types/Structures

The following structures should be used by the library:

type FileMetadata struct {
    Path     string `json:"path"`      // the file's absolute path
    Size     int64  `json:"size"`      // the file size in bytes
    IsBinary bool   `json:"is_binary"` // whether the file is a binary file or a simple text file
}
type FileStats struct {
    NumFiles        int64           `json:"num_files"`
    LargestFile     LargestFileInfo `json:"largest_file"`
    AverageFileSize float64         `json:"avg_file_size"`
    MostFrequentExt ExtInfo         `json:"most_frequent_ext"`
    TextPercentage  float32         `json:"text_percentage"`
    MostRecentPaths []string        `json:"most_recent_paths"`
}
type LargestFileInfo struct {
    Path string `json:"path"`
    Size int64  `json:"size"`
}
type ExtInfo struct {
    Extension      string `json:"extension"`
    NumOccurrences int64  `json:"num_occurrences"`
}

Guidelines

The library MAY define a structure/type/object on which the two required functions are to be called.

There is no guarantee that calls to AddFile() will happen sequentially.

Create a unit test for the library

Stage 2

Create a command line utility to uses the library. The utility reads a list of file metadata from standard input,

where each line is a JSON representation of the metadata. The utility calls AddFile() for each line, and finally

prints the output of GetStats() in JSON format when input ends.

Bonus:

create a Dockerfile for the executable.