Data-gen - data generation tool

Tool to generate json or csv files based on generic definitions
Example of a definition:

{
    "number": ["number", 100],
    "string": ["string", 3],
    "string-with-range": ["string-range", 3, 8],
    "string-with-placeholder": ["placeholder", "hello-*-test", 100],
    "random-from-collection": ["take-random", ["first", "second", "third", "fourth"]]
}

Example of one of the items generated from this definition:
in json:

{
  "number": 47,
  "string": "cVU",
  "string-with-range": "Bq2jO4t",
  "string-with-placeholder": "hello-96-test",
  "random-from-collection": "second"
}

in csv (order of columns is lexicographical order of keys in a definition hashmap)

81 third AXq hello-69-test Z05jhpup

Rationale

This tool was developed during an evaluation of different storage options for a completely unrelated project. I needed to generate a big amount of data to compare query times on big data sets.

How to run

If you have lein, you can run the app without building a jar file. Use ./bin/generate script with parameters.
Otherwise, you can use an already built jar file in the build folder.
java -jar data-gen and pass supported params.

Options

• -f — path to a file with definition (see section “Definitions” for more details)
• -d — name of a definition from the definitions file based on which data should be generated
• -n — into how many output files random output data should be split (useful when generating GBs of data)
• -s — size of a single output file in MBs (useful when generating GBs of data)
• -o — csv or json output format
• -u — path to an output folder
• -h — show help

Example

Generate 10 files, each of size ~5 GBs based on an “employee” definition from “some-definitions.json” file and put results into ./output folder.
java -jar data-gen.jar -f some-definitions.json -d employee -n 10 -s 5000 -o json -u ./output

Definitions

Generator value types and parameters are specified as tuples in a definition.
Example of a definition file that contains one main definition:

{
  "main": {
    "number": ["number", 100],
    "string": ["string", 3],
    "string-with-range": ["string-range", 3, 8],
    "string-with-placeholder": ["placeholder", "hello-*-test", 100],
    "random-from-collection": ["take-random", ["first", "second", "third", "fourth"]]
  }
}

Types:

• number - ["number", inclusive-upper-boundary]
• string - ["string", length-of-random-string]
• string-range - ["string-range", min-chars-in-string, max-chars-in-string(inclusive)]
• placeholder - ["placeholder", string-with-single-start-placholder, max-placeholder(inclusive)]
• take-random - ["take-random", array-with-items-from-which-to-pick]