go-csv

CSV generator written in Go

Dependencies

Go 1.21.4

Quick Usage

❯ go run main.go
 100% |█████████████████████████████████████████████████████████████████████| (5/5, 29732 it/s)
2024-02-17T10:27:52.525-0500    INFO    generator/generator.go:135      CSV generation complete {"filena
me": "out.csv"}

❯ cat out.csv
FNAME,LNAME,STREET,DOB,PICK_ONE,PATTERNITIZED,SOME_NUM
Roberta,Bartoletti,345 Creekmouth,1959-11-15,R,r0CUhz,1104
Zola,Nader,510 Capeport,1976-12-25,Y,_B_kQ4,558
Dasia,Kerluke,4154 West Landington,1969-04-01,R,2VBt23,914
Lydia,Bednar,5453 Heightsville,1967-05-18,B,ZkqQsO,551
Alta,Rau,276 New Causewayville,2003-07-29,B,hwMgWW,1145

Command help

❯ go run main.go -h
Usage of /var/folders/0t/w8j6n37s48g0b7kypjpbjp4w0000gn/T/go-build2512557781/b001/exe/main:
  -count int
        Number of records to generate (default 5)
  -help
        Show usage
  -input string
        Input filename (default "input/example.yaml")
  -output string
        Output filename (default "out.csv")

Configuration

See input/example.yaml for an example configuration file with annotations.

Available Constraints

Generic Constraint

A constraint that can be applied to any field and can be combined with both type and xxxConstraint.

genericConstraint:
  chanceToOmit: 0.1 # 10% chance of an empty string

chanceToOmit must be a decimal between 0 and 1. When a randomly generated decimal is less than the configured chanceToOmit, the value for that cell will be an empty string.

Num Constraint

numConstraint:
  min: 420
  max: 1337

Generate an integer between the specified min and max values (both required).

Time Constraint

timeConstraint:
  format: 2006-01-02
  min: 1945-01-01
  max: 2005-02-12

Generate a timestamp with the specified format between the specified min and max times.

Note: The time value used in the format field must match the Golang reference time Mon, 02 Jan 2006 15:04:05 MST, see https://www.geeksforgeeks.org/time-formatting-in-golang/.

String Constraint

stringConstraint:
  pattern: '^[a-zA-Z0-9_]{6}$'
  oneOf:
    - R
    - B
    - Y

Must specify either pattern, a regex pattern, or oneOf, a list of possible values, but cannot specify both. When using oneOf, a random entry in the list will be chosen as the value. All entries have equal weight. For differently weighted entries, either register a custom value function or provide multiple entries in oneOf corresponding to the desired weights.

stringConstraint:
  oneOf:
    - A
    - A
    - A
    - B

The above configuration will choose A 75% of the time and B 25% of the time.

Available Types

EMPTY
UINT64
UINT32
UINT8
FIRSTNAME
LASTNAME
STREET
CITY
STATE
ZIP
PHONE
EMAIL
COMPANY
YES_OR_NO
CONSISTENTLY_INCREASING_ID

Registering a custom value function

A custom function can be registered to a generator, exposing that function for use via the configuration yaml file. The function must match the generator.RandomValueFunc signature

type RandomValueFunc func(p FieldParams) string

package main

import (
	"fmt"
	"log"

	"github.com/TrevorEdris/go-csv/pkg/generator"
)

func main() {
	g, err := generator.NewGenerator("input/example.yaml", "out.csv")
	if err != nil {
		log.Fatalf("Failed to initialize generator: %s", err.Error())
	}

	err = g.RegisterNewValueFunction("ROW_NUMBER", myOwnValueFunction)
	if err != nil {
		log.Fatalf("Failed to register value function: %s", err.Error())
	}

	err = g.Generate(*count)
	if err != nil {
		log.Fatalf("Failed to generate CSV: %s", err.Error())
	}
}

func myOwnValueFunction(p generator.FieldParams) string {
	return fmt.Sprintf("ROW_NUMBER-%d", p.RowNumber)
}

fields:
- name: RowNum
  type: ROW_NUMBER # The value passed in to `g.RegisterNewValueFunction`

Contributing

Refer to the Contribution Guidelines for instructions on contributing to this project.

# README