sham

sham is a random data generator that uses a custom DSL for defining the data's shape.

Install

go get -u github.com/mattmeyers/sham/cmd/sham/...

Usage

sham is a tool for generating random data

Usage:

	sham [options] <schema>

Options:
	-f value	set the output format: json, xml (default json)
	-n int		the number of generations to perform (default 1)		
	-pretty		pretty print the result
	-h, --help	show this help message

To ensure the schema is not affected by any shell escaping, it is recommended that the schema be surrounded by single quotes.

Example

The following schema

{
    "name": name,
    "friends": [(1,5),
        {
            "name": name,
            "age": (20,30),
            "phone": /\(\d{3}\) \d{3}-\d{4}/,
            "job": /programmer|accountant|lawyer/
        }
    ]
}

will produce data such as

{
    "name": "John Doe",
    "friends": [
        {
            "name: "Bob Smith",
            "age": 21,
            "phone": "(555) 746-8193",
            "job": "programmer"
        },
        {
            "name: "Matt Doe",
            "age": 28,
            "phone": "(555) 395-1823",
            "job": "lawyer"
        }
    ]
}

Sham Language

The Sham language defines the structure of the random data. This language is a superset of JSON that adds integer ranges, generator functions, and regular expressions. For the full grammar, refer to doc/sham.ebnf. For the base JSON grammar, refer to RFC 8259. Sham adds three structures to this grammar:

Ranges

A range is an inclusive range of integers defined by the production

range : '(' INTEGER ',' INTEGER ')' ;

where the first integer is the min and the second is the max. This range includes both the min and max. If a range appears at the beginning of an array, the a random number of elements will be generated in the array. In any other position, a range will evaluate to a random integer in the range.

Terminal Generators

A terminal generator is a function identifier defined by the production

generator : [a-zA-Z][a-zA-Z]* ;

In the generated data, the terminal generator will be replaced by a single value. Generators must match a function defined by the sham CLI tool. Unkown generators will return a parsing error.

Regular Expressions

While regular expressions are normally used to match text, Sham provides the ability to instead generate data from a regular expression. Regular expressions are defined by the production

regex : '/' .* '/'

Note: This regular expression is simplified and technically incorrect. Any valid Go flavored regular expression should work though.

More generally, a regular expression is a string of characters enclosed by two / characters. These expressions are of the Go flavor.