Sample data generator - command-line utility and library
npm install datamakerA command-line Node.js script and library that generates JSON or CSV data in bulk. If you are building an IT system,
then the chances are you'll need to populate a database (whether SQL or NoSQL) with some reasonably realistic data
to test and benchmark with.
The datamaker tool allows sample data to be created by supplying:
- a template of how the data is to look. The data can contain multiple placeholders where sample data will be inserted e.g. {{firstname}},{{lastname}},{{date}}.
- the format of the output data: none, json or csv. This effects how the generated string data is processed prior to delivery.
- the number of records to be created.
Quick example:
``sh`
$ echo "{{uuid}},{{date}},{{firstname}} {{surname}},{{email}}" | datamaker --format csv --iterations 5
10U9SHHE2463IH9E,1970-10-12,Marylee Dodge,meagan-harwell@betaine.com
379QYC80U5KYQP4D,1994-11-09,Melany Fuqua,jennette.labonte@yahoo.com
DERC4Y2BQ6HCI0HI,1983-08-11,Cathleen Leal,earlenemattson@gmail.com
00K8FEGZJO31Q08O,2005-06-18,Louie Lee,tonisha.short@hotmail.com
JDYSVPTAEXKEF9D8,1982-10-29,Dionne Vann,martin.renfro@hemicrane.com
Node.js & npm are required to be pre-installed.
To install the command-line utility, use npm:
`sh`
$ npm install -g datamaker
or add the library to an existing Node.js project:
`sh`
$ npm install --save datamaker
- --template/-t - the path of the template file e.g --template /path/to/template.txt
- /-f - the target file format (none, csv, json or xml). Default none e.g. --format json
- /-i - the number of records to create. Default 1 e.g. --iterations 5000
- /-l - list the available tags
The template for a CSV file can be stored in a text file and supplied with the --template/-t parameter. Create a text file containing the following template:
`
{{uuid}},{{date}},{{time}},{{firstname}} {{surname}},{{street}},{{town}},{{zip}} {{statecode}},{{longitude}},{{latitude}}
The template contains the layout of each line of data, with placeholders for where the dynamic data is inserted. Save it as template.txt.
You may now run datamaker using this template:
`sh`
$ datamaker -t ./template.txt -f csv -i 500
Alternatively, you can pipe in the template from elsewhere:
`sh`
$ echo "{{uuid}},{{date}},{{firstname}} {{surname}},{{zip}}" | datamaker --format csv --iterations 10000
JSON data is generated in a similar way. This time our template represents a single JSON document:
`js`
{
"_id": "{{uuid}}",
"name": "{{firstname}} {{surname}}",
"occupation": "{{occupation}}",
"religion": "{{religion}}",
"dob": "{{date 2014-01-01}}",
"status": "{{oneofl ok provisional rejected cancelled deleted}}",
"accountType": "{{oneof bronze silver gold}}",
"password": "{{password | sha256}}",
"salt": "{{ words 5 | sha512}}",
"lastIP": "{{ ip }}",
"lastLogin": "{{date_iso 2020-01-01}}",
"location": {
"longitude": "{{ longitude NYC }}",
"latitude": "{{ latitude NYC }}"
},
"address": {
"street": "{{street}}",
"town": "{{town}}",
"postode": "{{postcode}}"
},
"telephone": "{{tel}}",
"pets": ["{{cat}}","{{dog}}"],
"email": "{{email true}}",
"url": "{{website}}",
"description": "{{words 20}}",
"((loop children 4))":"{{firstname}}",
"((loop friends 3))": {"name": "{{name}}", "email": "{{email}}"}
}
Save the template as template.json.
Run the datamaker as before but with json as the format parameter:
`sh`
$ datamaker -t ./template.json -f json -i 500
{"_id":"e87691f3232e493a8f7d5ed866bbf813","name":"Gertrude Ashcraft","occupation":"Television production assistant","religion":"Jeung San Do","dob":"2022-06-17","status":"cancelled","accountType":"silver","password":"6ae95ca5f8098007fc09f75761e85d4d1f6c9dc16e3f1679de4196127b0387b7","salt":"ccf2adf7bd7590eb2444c2ca0393805c534f60686c877b0a12c32dc645f9006d8ea3df9aeb0ebbeba941bb9cc54b3f6688b614ccfbcfa6954f86ba66fbec76e5","lastIP":"83.118.14.45","lastLogin":"2022-06-09T13:25:44.406Z","location":{"longitude":"-73.9759","latitude":"40.7312"},"address":{"street":"6681 Shipley","town":"Caister on Sea","postode":"RH5 7XD"},"telephone":"+597-4041-660-496","pets":["Rusty","Roxy"],"email":"gertrude.ashcraft6@hotmail.com","url":"https://toronto.com","description":"bedding insertion advisory bunch terms manual language parameter gs jurisdiction experiment signing gratuit cheapest initiative kai proxy anniversary prescribed penetration","children":["Idalia","Allyson","Jadwiga","Luci"],"friends":[{"name":"Dalila Dunbar","email":"judi.laughlin@friend.com"},{"name":"Tambra Caraway","email":"virgil_cornell@vitamin.nr"},{"name":"Cathleen Rivero","email":"kathleen_card54@gmail.com"}]}
...
Only in JSON-Templates you may use the loop-command to create an Array of data.
Usage:
`json`
"((loop property number[,max]))":{}
- property will be the name of the array
- number is the number of times to repeat the object into the resulting array. if used with a second number, a random number between these two will be used, eg. "((loop tags 2,9))": "{{word}}"
Example:
`json`
{
"((loop items 2))": {
"name":"{{word}}",
"price":"{{price}}"
}
}
results in
`json
{
"items": [
{
"name":"some",
"price":"2.50"
},
{
"name":"item",
"price":"4.30"
}
]
}
`
> Note: to use the ((loop .. )) syntax, you must be using JSON mode (i.e. -f json and the template itself must parse as JSON correctly, which in practice means using no generated numbers or boolans).
Create an XML template e.g. template.xml:
`xml`
Run the datamaker as before but with xml as the format parameter:
`sh`
$ datamaker -t ./template.xml -f xml -i 500
...
Combining this tool with the couchimport utility allows data to be generated and imported into the a Cloudant/CouchDB database in one go:
`sh`
$ datamaker -t ./template.json -f json -i 1000 | couchimport --db mydatabase
Reading data from stdin
written {"batch":1,"batchSize":500,"docSuccessCount":500,"docFailCount":0,"statusCodes":{"201":1},"errors":{}}
written {"batch":2,"batchSize":500,"docSuccessCount":1000,"docFailCount":0,"statusCodes":{"201":2},"errors":{}}
Import complete
The couchimport utility bundles the JSON into bulk API calls and posts them to the database via HTTP.
A datamaker tag can also include optional filters by supplying strings after a | character e.g.
`
$ echo '{{ name | toUpperCase }}' | datamaker
JANYCE MOE
Filters can be chained e.g.
`
$ echo '{{ words 5 | toUpperCase | toArray}}' | datamaker
["BUDAPEST","LICENSING","GMC","METHODOLOGY","MEM"]
$ echo '{{ name | toLowerCase | sha256 }}' | datamaker
76576efc53b4441d342acbca485457f948c1b97c4a2515a05ffc47aa524b5093
- toUpperCase
-
-
-
-
-
-
-
-
-
-
-
-
-
-
- - replaces single quotes withe two single quotes, handy when generating SQL.escapeDoubleQuotes
- - replaces double quotes with two double quotes.
Additionally for JSON formats, the following filters can be used within templates to output appropriate JSON datatypes:-
- toBool
-
-
-
As well as performing type conversion, these functions also "eat" up any double quotes around the host tag e.g.
`js`
{
"alive": "{{boolean 0.75 | toBool}}",
"count": "{{integer | toInt}}",
"score": "{{float | toFloat}}"
}
returns:
`js`
{
"alive": true,
"count": 10,
"score": 5.0
}
which is useful for making both the original template and the resultant object parse as valid JSON.
The Mustache-style tags you may use are listed below. Some tags allow extra parameters to be supplied to affect the range of random data generated
The code for the tags can be found in the plugins folder of the source code.
- A-E - addressuk addressus addressgerman airport autoinc boolean cat city cityGerman clf company country creditcard currency date date_iso digits dog domainname email emojii ethnicity
- F-O - file firstname float http_method http_path http_query_string http_reponse integer ip ip6 kuuid kuuidr last latitude letters longitude mac marque monarch name normal occupation oneof oneofl
- P-T - password president postcode price prime product religion sic state statecode street streetGerman surname tel time timestamp title tld town
- U-Z - unit url uuid uuidv4 uuidv7 walk website word words youtube zip
Single-line UK address.
Parameters: none
e.g.
`
{{addressuk}} ---> 9315 Lancaster Circle, Haslingden, Nottinghamshire, HS15 6YD
Single-line US address.
Parameters: none
e.g.
`
{{addressus}} ---> 8184 Ambrose, Fontana, Minnesota, 44626
Single-line German address.
Parameters: none
e.g.
`
{{addressgerman}} ---> Bahnhofsstrasse 12, 80335 München
Three-digit airport code.
Parameters: none
e.g.
`
{{airport}} ---> MTK
Auto-incrementing number.
Parameters:
- starting number (default 1)
e.g.
`
{{autoinc 1000}} ---> 1000
{{autoinc}} ---> 1001
Boolean value.
Parameters:
- probability of being true (default 0.5)
e.g.
`
{{boolean}} ---> false
{{boolean 0.95}} ---> true
Cat name.
Parameters: none
e.g.
`
{{cat}} ---> Smokey
US city name.
Parameters: none
e.g.
`
{{city}} ---> Fremont
German city name.
Parameters: none
e.g.
`
{{cityGerman}} ---> Berlin
Log line in Common Logfile Format.
Parameters: none
e.g.
`
{{clf}} ---> 208.148.153.238 - lelah [29/Aug/2024:14:22:49 +0100] "GET /reel/hip.html HTTP/1.0" 200 71733
Company name.
Parameters: none
e.g.
`
{{company}} ---> Venusian Software Corp
Country name.
Parameters: none
e.g.
`
{{country}} ---> Lebanon
UK county name.
Parameters: none
e.g.
`
{{county}} ---> Derbyshire
Credit card number.
Parameters: none
e.g.
`
{{creditcard}} ---> 6011867289904845
Currency code.
Parameters: none
e.g.
`
{{currency}} ---> USD
Random date in YYYY-MM-DD format.
Parameters:
- min - minimum date or 'now' if the timestamp is to be the current date (default '1970-01-01')
- max - maximum date (default 'now')
e.g.
`
{{date}} ---> 1977-02-28
{{date 2015-01-01}} ---> 2018-08-02 // date after 2015-01-01
{{date 2015-01-01 2016-01-01}} ---> 2015-04-23 // date in 2015
{{date now}} ---> 2024-07-02 // the current date
Random date in ISO-8601 format.
Parameters:
- min - minimum date or 'now' if the timestamp is to be the current date/time (default '1970-01-01')
- max - maximum date (default 'now')
e.g.
`
{{date_iso}} ---> 2013-05-24T02:44:04.687Z
{{date_iso 2015-01-01}} ---> 2018-07-09T22:15:30.512Z // date after 2015-01-01
{{date_iso 2015-01-01 2016-01-01}} ---> 2015-04-21T18:08:33.979Z // date in 2015
{{date_iso now}} ---> 2024-07-02T10:55:52.002Z // the current date
String of numerals.
Parameters:
- numDigits (default 5)
e.g.
`
{{digits}} ---> 06984
{{digits 8}} ---> 61103920
Dog name.
Parameters: none
e.g.
`
{{dog}} ---> Lucky
Domain name.
Parameters: none
e.g.
`
{{domainname}} ---> yallaer.com
Email address.
Parameters:
- whether to use the previous firstname/surname for the email generation
e.g.
`
{{email}} ---> jermaine.buchanan@drilling.com
$3
Emojii.
Parameters:
- numChars - number of characters (default 1)
e.g.
{{emojii}} ---> 👦
{{emojii 3}} ---> 🌹⛔💺
$3
Ethnicity string.
Parameters: None
e.g.
{{ethnicity}} ---> Tuscan
$3
Get a random line from a simple text-file, e.g.
line1
another line
yeah
Parameters:
- filename - full path to the file (no default)
e.g.
{{file /path/to/file.txt}} ---> line1
$3
Human first name.
Parameters:
e.g.
{{firstname}} ---> Bethan
$3
Floating point number.
Parameters:
- min (default 1)
- max (default 100)
- decimalPlaces (default 4)
e.g.
{{float}} ---> 13.8592
{{float 1000 2000 2}} ---> 1750.06
$3
HTTP method. Either GET/PUT/POST/DELETE/HEAD/COPY, much more likely to be GET.
Parameters:
- n/a
e.g.
{{http_method}} ---> GET
$3
HTTP path.
Parameters:
- n/a
e.g.
{{http_path}} ---> /curious/ranch/viruses.html?barriers=AJEAZDLK65QFHKZ1
$3
An HTTP query string.
Parameters
- None
e.g.
{{http_query_string}} ---> ?offering=26&approaches=electricity&unsigned=sectors&actively=villa&adam=81ZVYDTDPXQTSK4J
$3
HTTP response code. Either 200/400/401/403/302/500, much more likely to be 200.
Parameters:
- n/a
e.g.
{{http_response}} ---> 200
$3
Integer number.
Parameters:
- min (default 1)
- max (default 100)
e.g.
{{integer}} ---> 99
{{integer 1000 2000}} ---> 1523
$3
IP4 address.
Parameters:
- local - boolean (whether to generate an IP in the 192.168.1 range or not)
e.g.
{{ip}} ---> 63.235.50.110
{{ip true}} ---> 192.168.1.58
$3
IP6 address.
Parameters:
- local - boolean (whether to generate an IP in the fc00::: range or not)
e.g.
{{ip6}} ---> 487d:375d:7bfe:b23b:d1e2:8934:cfb2:c17e
{{ip true}} ---> fc00:cefe:5dfc:14da:691d:b4bf:63ac:6d17
$3
Time-sortable, unique identifier. see here
Parameters:
- min (optional) - minimum date
- max (optional) - maximum date
e.g.
{{kuuid}} ---> 001g8LWk0Svk222Bd0Et0GeaBl1P1gkP
{{kuuid 2010-01-01 2019-01-01}} ---> 001eWhUE2HLix22HqmL5436NDm1p02X6
$3
Time-sortable, unique identifier, but in reverse order. see here
Parameters:
- min (optional) - minimum date
- max (optional) - maximum date
e.g.
{{kuuidr}} ---> zzzwSGtT2o36oK17mC4R26dkHI1f1Xm0
{{kuuid 2010-01-01 2019-01-01}} ---> zzyTAKwG1uzH1N4Cl4xi1vZIE22oxrrT
$3
The last generate value of the supplied tag. This is used to re-use generated data elsewhere in your template.
Parameters:
- tag - the name of the tag
e.g.
{{last uuid}} ---> HSFC5LQPCP84IVY7 (the last uuid that was generated by datamaker)
$3
Decimal latitude.
Parameters:
- city - one of
, NYC, TOK, SYD or PAR. If omitted a latitude anywhere in the world will by returned.e.g.
`
{{latitude}} ---> -54.4371
{{latitude PAR}} ---> 48.8823
$3
String of uppercase characters.
Parameters:
- numLetters (default 5)
e.g.
{{letters}} ---> TVEHJ
{{letters 10}} ---> WOBOJRJFCU
$3
Decimal longitude.
Parameters:
- city - one of
, NYC, TOK, SYD or PAR. If omitted a longitude anywhere in the world will by returned.e.g.
`
{{longitude}} ---> 175.2526
{{longitude PAR}} ---> 2.3815
$3
Mac address
Parameters: none
e.g.
{{mac}} ---> 23-0d-a3-3e-cf-d8
$3
Car manufacturer.
Parameters: none
e.g.
{{marque}} ---> Bugatti
$3
King or Queen.
Parameters: none
e.g.
{{monarch}} ---> Henry VIII
$3
Occupation string.
Parameters: none
e.g.
{{occupation}} ---> Midwife
$3
Picks one of supplied values with an equal chance of each value appearing. See also oneofl.
Parameters: any number of strings
e.g.
{{oneof Gryffindor Hufflepuff Ravenclaw Slytherin}} ---> Slytherin
$3
Picks one of supplied values, items at the start of the list are much more likely to be returned. (the
in oneofl stands for "Log", as the Math.log10 function is used to get a non-linear probability of returning array items.)Parameters: any number of strings
e.g.
`
{{oneofl complete new rejected cancelled }} ---> complete
Here's the distribution of results:
sh
echo '{{oneofl a b c d e f g h i j k l m }}' | datamaker -i 10000 | sort | uniq -c
2692 a
1550 b
1097 c
860 d
675 e
541 f
465 g
421 h
388 i
393 j
317 k
308 l
293 m
`$3
Combination for firstname and surname. Equivalent of
.Parameters: none
e.g.
`
{{name}} ---> Anna Flint
$3
Generates numbers on a normal distribution
Parameters:
- mean - centre of distribution (default 50)
- stddev - standard deviation (default 1)
- decimalPlaces - number of decimal places (default 4)
e.g.
{{normal}} ---> 50.1097
{{normal 20000 1000 2}} ---> 20370.88
$3
A commonly-used password.
Parameters: none
e.g.
{{password}} ---> abcd1234
{{password | md5}} ---> 1f3870be274f6c49b3e31a0c6728957f
$3
A US president
Parameters: None
e.g.
{{president}} ---> Richard Nixon
$3
UK postcode.
Parameters: none
e.g.
{{postcode}} ---> KT4 0XS
$3
Floating point price.
Parameters:
- min (default 1)
- max (default 100)
e.g.
{{price}} ---> 65.29
{{price 500 700}} ---> 521.98
$3
Prime number. If you supply impossible parameters, you will get _1_ in reply.
Parameters:
- min (default 1)
- max (default 100)
e.g.
{{prime}} ---> 17
{{prime 1000 3000}} ---> 1657
$3
Product name.
Parameters:
- None
e.g.
{{product}} ---> CARABAO
{{product | toTitleCase}} ---> Salt
$3
Religion
Parameters: none
e.g.
{{religion}} ---> Mandaean Nasaraean Sabeans
$3
Industry standard SIC code - business category
Parameters: none
e.g.
{{sic}} ---> Growing of tobacco
$3
US state name.
Parameters: none
e.g.
{{state}} ---> Ohio
$3
2-letter US state code.
Parameters: none
e.g.
{{statecode}} ---> NC
$3
Street address.
Parameters: none
e.g.
{{street}} ---> 6502 Chantler Avenue
$3
German Street name.
Parameters: none
e.g.
{{streetGerman}} ---> Schulstrasse
$3
Human surname.
Parameters: none
e.g.
{{surname}} ---> Doyle-Tyson
$3
International telephone number.
Parameters: none
e.g.
{{tel}} ---> +43-3040-100-474
$3
Time in HH:MM:SS format.
Parameters: none
e.g.
{{time}} ---> 10:45:59
$3
Timestamp in milliseconds since 1970.
Parameters:
- min - minimum timestamp (default 0)
- max - maximum timestamp (default 'now')
e.g.
{{timestamp}} ---> 351543517819
{{timestamp 946684800000}} --> 1163308913102 // timestamp after 2000-01-01
{{timestamp 946684800000 978307200000}} --> 959753617250 // timestamp in year 2000
$3
Honorific or title e.g. Mr, Mrs etc.
Parameters: none
e.g.
{{title}} ---> Reverend
$3
Top level domain, or common domain name ending.
Parameters: none
e.g.
{{tld}} ---> gov.pr
$3
UK town name.
Parameters: none
e.g.
{{town}} ---> Dudley
$3
An SI Unit
Parameters: none
e.g.
{{unit}} ---> °C
$3
Full URL.
Parameters: none
e.g.
{{url}} ---> https://www.jovinianist.com/microcosmology.html?adrenalone=VEF0TSB23N04V8MO
$3
Unique identifier.
Parameters: none
e.g.
{{uuid}} ---> C3QTU8YIVKZY126Q
$3
Unique identifier v4.
Parameters: none
e.g.
{{uuidv4}} ---> d1e606b0-0452-46a7-9190-8671a82fdea0
$3
Unique identifier v7.
Parameters:
- min (optional) - minimum date
- max (optional) - maximum date
e.g.
{{uuidv7}} ---> 00b0bca5-3cf3-7ba1-a4e7-097295433ee7
{{uuidv7 1970-01-01 1970-01-02 }} ---> 0000001a-c8d1-7026-a44a-98c438ee931d
$3
Random walk. A single floating point number that "walks" in value between invocations.
Parameters:
- start - the start value (Default: 0)
- inc - the max increment (Default: 1)
- places - the number of decimal places in the output (Default: 4)
- ref - a reference for this value, so that multiple "walk" tags can be used in the same datamaker template (Default: ref)
e.g.
{{walk}} ---> -0.4405
{{walk 50 0.5 6 x}} ---> 50.099534
{{walk -1.1 0.2 6 y}} ---> -1.163953
{{walk 50 0.5 6 x}} ---> 50.311757
{{walk -1.1 0.2 6 y}} ---> -0.965426
$3
Full website URL.
Parameters: none
e.g.
{{website}} ---> http://unlyrically.com
$3
Single word.
Parameters: none
e.g.
{{word}} ---> synentognathous
$3
Multiple words.
Parameters:
- count (default 5)
e.g.
{{words}} ---> piacularly burp archisymbolical glumaceous Calinago
{{words 2}} --->Xenomorpha mauler
$3
Random YouTube URL.
Parameters: none
e.g.
{{youtube}} ---> https://www.youtube.com/watch?v=dQw4w9WgXcQ
$3
US ZIP code.
Parameters: none
e.g.
{{zip}} ---> 69882
Using as a library
You can use this npm module as a library in your own code
js
import * as datamaker from 'datamaker'
const template = '{{title}} {{firstname}} {{surname}}'
const format = 'none'
const iterations = 500
datamaker.generate(template, format, iterations)
.on('data', (d) => { console.log(d) })
.on('end', (d) => { console.error('Done!') })
`or there are helper functions that return Promises e.g.
js
// get a single item
await dg.single('{{uuid}},{{name}}', 'csv')
// get a batch of 50 items
await dg.batch('{"name": "{{name}}","email": "{{email}}"}', 'json', 50)
`$3
When using datamaker as a library it is possible to extend its capability by defining custom plugins to suit the individual needs of a project. A custom plugin should be located inside the
folder at the root of the applications project with each plugin created as a separate js file within a namespace folder allowing plugins to referenced in templates as {{namespace:plugin}}. For example:`
datamaker
└── plugins
└── myorg
└── employeeid.js
With the custom
plugin defined as follows:`js
module.exports = () => {
const min = 1000000
const max = 3000000
return (Math.floor(min + Math.random() * (max - min))).toString()
}
`The custom plugin can then be referenced in a template using
as follows:`js
import * as datamaker from 'datamaker'
const template = '{{myorg:employeeid}} {{title}} {{firstname}} {{surname}}'
const format = 'none'
const iterations = 5
datamaker.generate(template, format, iterations)
.on('data', (d) => { console.log(d) })
.on('end', (d) => { console.error('Done!') })
`Resulting in the following:
2286807 Mr Athena Bowles
1727729 Prof Heidi Barrow
2411511 Mr Lawanna Karr
2898717 Mrs Londa Wingate
1756263 Ms Lashay Pitre
Formatting
The
/-f parameter defines- how the text in each substition is pre-processed before output e.g. in
json mode double quotes are escaped correctly.
- how each line of output is processed prior to output e.g. in json mode the completed template is parsed to check it is valid JSON before being output on a a single line followed by a \n characterThe code for the formatters can be found in the
formatters folder of the source code.A note on the data
The data generated by this tool is biased towards UK and US data sets. The names, towns, streets and postcodes are gleaned from western data sets. If you need data that resembles a different geography or contains more challenging character sets, then the feel free to fork the code and modify the stock data from the
plugins folder or follow the guidance above and add your own specific custom plugins.Note that generating an address with
{{street}},{{city}},{{state}},{{statecode}}{{zip}} will generate that appears at a glance to be a reasonble address, but is patently nonsense:`sh
$ echo "{{street}},{{city}},{{state}},{{statecode}}{{zip}}" | datamaker
6682 Crowcroft Circle,Nashua,New York,UT00769
``The plugins do not coordinate with each other to ensure that the street exists in the city, or that the city exists in the state, or that the state code matches the state. That would require a more sophisticated and much larger data set!
Also note that the email addresses, zip codes, domain names, telephone numbers, websites and postcodes are fabricated. Airports, towns, states, state codes, cities, counties, countries and currencies are real.