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Generator configuration

timeMultiplier

Commentary​

added in 0.5.7

global configuration

Changes the rate at which wallclock speed advances. Higher numbers speed time up. Lower numbers slow time down.

For example, a factor of 4 speeds time up by 4x, whereas a factor of .25 slows time down by 4x. A value of 1 matches the real clock speed and won't change anything.

The effect is that slower wallclock speeds allow generators to do more work in a given interval of wallclock time, and faster speeds allow generators to do less work.

The factor can be dynamic and chosen from a function. 1

Examples​

Speeding time up​

Use a value greater than 1 to speed time up. This example runs wallclock speed at 4x faster than its normal pace.

{
    "generators": [
        {
            "topic": "sandbox",
            "value": {
                "now": {
                    "_gen": "formatDateTime",
                    "ms": {
                        "_gen": "now"
                    }
                }
            }
        }
    ],
    "globalConfigs": {
        "timeMultiplier": 4
    },
    "connections": {
        "kafka": {
            "kind": "kafka",
            "producerConfigs": {
                "bootstrap.servers": "localhost:9092",
                "key.serializer": "io.shadowtraffic.kafka.serdes.JsonSerializer",
                "value.serializer": "io.shadowtraffic.kafka.serdes.JsonSerializer"
            }
        }
    }
}

Slowing time down​

Use a value less than 1 to slow time down. This example runs wallclock speed at 4x slower than its normal pace.

{
    "generators": [
        {
            "topic": "sandbox",
            "value": {
                "now": {
                    "_gen": "formatDateTime",
                    "ms": {
                        "_gen": "now"
                    }
                }
            }
        }
    ],
    "globalConfigs": {
        "timeMultiplier": 0.25
    },
    "connections": {
        "kafka": {
            "kind": "kafka",
            "producerConfigs": {
                "bootstrap.servers": "localhost:9092",
                "key.serializer": "io.shadowtraffic.kafka.serdes.JsonSerializer",
                "value.serializer": "io.shadowtraffic.kafka.serdes.JsonSerializer"
            }
        }
    }
}

Varying the speed​

Use functions to dynamically choose the rate. In this example, every other minute slows time down by 2x, and all other moments in time are sped up to 100x.

{
    "generators": [
        {
            "topic": "sandbox",
            "value": {
                "now": {
                    "_gen": "formatDateTime",
                    "ms": {
                        "_gen": "now"
                    }
                }
            }
        }
    ],
    "globalConfigs": {
        "timeMultiplier": {
            "_gen": "intervals",
            "intervals": [
                [
                    "*/2 * * * *",
                    0.5
                ]
            ],
            "defaultValue": 100
        }
    },
    "connections": {
        "kafka": {
            "kind": "kafka",
            "producerConfigs": {
                "bootstrap.servers": "localhost:9092",
                "key.serializer": "io.shadowtraffic.kafka.serdes.JsonSerializer",
                "value.serializer": "io.shadowtraffic.kafka.serdes.JsonSerializer"
            }
        }
    }
}

Specification​

JSON schema​

{
    "oneOf": [
        {
            "type": "number"
        },
        {
            "type": "object",
            "properties": {
                "_gen": {
                    "type": "string"
                }
            },
            "required": [
                "_gen"
            ]
        }
    ]
}