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

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

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.

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"
        }
    ]
}

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:

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.

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.

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.