Hello JR

JR is a CLI program that helps you to create quality random data for your applications.

Basic usage

JR is very straightforward to use. Here are some examples:

Listing existing templates

jr template list

Templates are in the directory $JR_HOME/templates. JR_HOME defaults to ~/.jr and can be changed to a different dir, for example:

JR_HOME=~/jrconfig/ jr template list

Templates with parsing issues are showed in red, Templates with no parsing issues are showed in green

Create random data from one of the provided templates

Use for example the predefined net_device template to generate a random JSON network device

jr template run net_device

It’s also possible to use a shorter version of the command

jr run net_device

Other options for templates

If you want to use your own template, you have several options:

• put it in the templates directory
• embed it directly in the command using the --embedded flag

For a quick and dirty test, the best option is to embed directly a template in the command:

jr run --embedded "name:{{name}}"

Create more random data

Using -n option you can create more data in each pass. This example creates 3 net_device objects at once:

jr run net_device -n 3

Continuous streaming data

Using --frequency option you can repeat the creation every f milliseconds

This example creates 2 net_device every second, for ever:

jr run net_device -n 2 -f 1s 

Using --duration option you can time bound the entire object creation. This example creates 2 net_device every 100ms for 1 minute:

jr run net_device -n 2 -f 100ms -d 1m

Results are by default written on standard out (--output "stdout") with this output template:

"{{.V}}\n"

which means that only the “Value” is in the output. You can change this behaviour embedding a different template with --outputTemplate

This example will show the key too, which is null if not specified

jr template run --outputTemplate '{{.K}} {{.V}}' net_device 

This example will generate a key and print it:

jr template run --key '{{key "ID" 100}}' --outputTemplate '{{.K}} {{.V}}' net_device

In this example --kcat is used, which is equivalent to --outputTemplate '{{.K}},{{.V}}'

jr run net_device -n 2 -f 100ms -d 1m --kcat

If you want syntax colouring and your output is just json, you can pipe standard output to jq

jr run net_device -n 2 -f 100ms -d 1m | jq

Beware that if you, for example, include the key in the output, it won’t be possible to use jq if the output is not a valid json.

jr run net_device -n 2 -f 100ms -d 1m --kcat | jq

parse error: Expected value before ',' at line 1, column 5