Go interview question - Synthetic Data Generator

main.go

// # Problem Statement
//
// We need a tool to generate massive amounts of synthetic data for testing our pipelines. Your task is to build a configurable engine that takes a JSON schema and outputs all the generated data to standard output.
//
// # Requirements
//
// 1. The generator must support these 3 field types:
//  * `sequence`: An auto-incrementing integer (e.g., 1, 2, 3...) starting from 1.
//  * `name`: A random name from the pre-defined set of names.
//  * `formula`: A template that should be parsed and executed to derive the value.
// 2. Program should be buildable and output expected result.
// 3. Output should be deterministic.
// 4. No requirements to the output format, it can be CSV, JSON or just printed out as is.
//
//
// **Example input:**
//
// {
//   "count": 5,
//   "seed": 1,
//   "fields": [
//     { "name": "id", "type": "sequence" },
//     { "name": "name", "type": "name" },
//     { "name": "description", "type": "formula", "formulaValue": "{{ .name }}'s ID is {{ .id }}" }
//   ]
// }
//
//
// **Example output:**
//
// id, name, description
// 1, Bob, Bob's ID is 1
// 2, Alice, Alice's ID is 2

package main

import (
  "encoding/json"
  "fmt"
)

// Config represents the input JSON structure
type Config struct {
  Count  int     `json:"count"`
  Seed   int     `json:"seed"`
  Fields []Field `json:"fields"`
}

// Field represents a single column definition
type Field struct {
  Name         string  `json:"name"`
  Type         string  `json:"type"` // sequence, name, formula
  FormulaValue *string `json:"formulaValue,omitempty"`
}

var names = []string{"Alice", "Bob", "John"}

func main() {
  jsonData := `
  {
    "count": 5,
    "fields": [
      { "name": "id", "type": "sequence" },
      { "name": "name", "type": "name" },
      { "name": "desc", "type": "formula", "formulaValue": "{{ .name }}'s ID is {{ .id }}" }
    ]
  }`

  var config Config
  if err := json.Unmarshal([]byte(jsonData), &config); err != nil {
    panic(err)
  }

  // TODO: Implement the generator logic here
  fmt.Println("Generating data...")
}