Mock data generator for testing

In 9.1.0, SkyWalking adds a module to generate mock data for testing. You can use this module to generate mock data that will be sent to the storage.

To start the data generator, execute the script tools/data-generator/bin/start.sh.

Note that SkyWalking doesn’t release a Docker image for this module, but you can still build it yourselves by running the commands:

# build a Docker image for local use
make docker.data-generator

# or push to your registry
export HUB=<your-registry>
make push.docker.data-generator

Currently the module can generate two kinds of SkyWalking data, segments and logs. For each type, there are some generators that can be used to fill the fields.

Generate mock data

To generate mock data, POST a request to URL path /mock-data/segments/tasks (segments) or /mock-data/logs/tasks (logs) with a generator template:

curl -XPOST 'http://localhost:12800/mock-data/segments/tasks?size=20' -H'Content-Type: application/json' -d "@segment-template.json"

curl -XPOST 'http://localhost:12800/mock-data/logs/tasks?size=20' -H'Content-Type: application/json' -d "@logs-template.json"

There are two possible types of task to generate mock data, size and qps:

• size (/mock-data/segments/tasks?size=20): the task will generate total number of size segments/logs and then finish.
• qps (/mock-data/segments/tasks?qps=20): the task will generate qps segments/logs per second continuously, until the task is cancelled.

Refer to the segment template, the log template and the Generators for more details about how to compose a template.

Cancel a task

When the task is acknowledged by the server it will return a task id that can be used to cancelled the task by sending a DELETE request to URL path /mock-data/logs/tasks with a parameter requestId (i.e. /mock-data/logs/tasks?requestId={request id returned in previous request}):

curl -XDELETE 'http://localhost:12800/mock-data/segments/task?requestId=70d8a39e-b51e-49de-a6fc-43abf80482c1'
curl -XDELETE 'http://localhost:12800/mock-data/logs/task?requestId=70d8a39e-b51e-49de-a6fc-43abf80482c1'

Cancel all tasks

When needed, you can also send a DELETE request to path /mock-data/segments/tasks to cancel all segment tasks.

curl -XDELETE 'http://localhost:12800/mock-data/segments/tasks
curl -XDELETE 'http://localhost:12800/mock-data/logs/tasks

Generators

uuid

uuid generator leverages java.util.UUID to generate a string. You can use uuid generator to fill the traceId field of segments.

changingFrequency property can be used when you want to reuse a uuid for multiple times, for example, if you want a traceId to be reused by 5 segments, then setting changingFrequency to 5 would do the trick. By setting changingFrequency to 5, uuid generates 1 string, and uses it for 5 times, then re-generates a new uuid string and uses it for another 5 times.

"traceId": {
    "type": "uuid",
    "changingFrequency": "5"
}

randomString (String)

length (int)

length specifies the length of the random string to be generated, i.e. generatedString.length() == length is always true.

prefix (String)

prefix is always added to the random strings after they are generated, that means:

• generatedString.startsWith(prefix) is always true, and,
• generatedString.length() == length + prefix.length() is always true.

letters (boolean)

Specifies whether the random string contains letters (i.e. a-zA-Z).

numbers (boolean)

Specifies whether the random string contains numbers (i.e. 0-9).

domainSize (int)

When generating random strings, you might just want some random strings and use them over and over again randomly, by setting domainSize, the generator generates domainSize random strings, and pick them randomly every time you need a string.

randomBool (boolean)

This generator generates a Boolean value, true or false with a default possibility of 50%, while you can change the possibility below.

possibility (double, [0, 1])

possibility is a double value >= 0 and <= 1, it’s 0.5 by default, meaning about half of the generated values are true.

To always return a fixed boolean value true, you can just set the possibility to 1, to always return a fixed boolean value false, you can set the possibility to 0

"error": {
    "type": "randomBool",
    "possibility": "0.9"
}

90 percent of the generated values are true.

randomInt (long)

min (long)

The minimum value of the random integers, meaning all generated values satisfy generatedInt >= min.

max (long)

The maximum value of the random integers, meaning all generated values satisfy generatedInt < min.

domainSize (int)

This is similar to randomString’s domainSize.

randomList (list / array)

size (int)

The list size of the generated list, i.e. generatedList.size() == size.

item (object)

item is a template that will be use as a prototype to generate the list items, for example when generating a list of Tag, the item should be the prototype of Tag, which can be composed by the generators again.

"tags": {
    "type": "randomList",
    "size": 5,
    "item": {
        "key": {
            "type": "randomString",
            "length": "10",
            "prefix": "test_tag_",
            "letters": true,
            "numbers": true,
            "domainSize": 10
        },
        "value": {
            "type": "randomString",
            "length": "10",
            "prefix": "test_value_",
            "letters": true,
            "numbers": true
        }
    }
}

fixedString (string)

This generator always returns a fixed value of string.

sequence (long)

sequence generator generates a sequence of monotonically increasing integers, with a configurable fluctuation.

min (long)

The minimum value of the sequence.

max (long)

The maximum value of the sequence.

step (long)

The increasing step of this sequence, i.e. the next generated value == the previous value + step.

domainSize (int)

This is similar to randomString’s domainSize.

fluctuation (int)

By default, sequence is strictly increasing numbers, but in some cases you might want the numbers to fluctuate slightly while they are increasing. Adding property fluctuation to the generator will add a random number >= -fluctuation, <= fluctuation to the sequence elements.

For example, min = 10, max = 15, step = 1 generates a sequence [10, 11, 12, 13, 14, 15], but adding fluctuation = 2 might generate a sequence [10, 12, 11, 14, 13, 15].