Trigger Map

The trigger map is the core part of dranspose and answers the following question:

Question

Which frames from which streams belong to the same event and have to be processed by the same worker with which tags?

It is a matrix which can express all required combinations. Instead of assigning workers directly, the trigger map only holds virtual workers. A guarantee is that if the same virtual worker is responsible for two frames, the same real worker will get both.

Virtual Workers

A virtual worker hold a list of tags, which must be a subset of the tags held by the actual worker.

An optional containt can be applied such that frames with the same constraint are delivered to the same worker. Note that for a new constraint, only the first VirtualWorker tags are considered as subsequent frames are necessarily delivered to the same actual worker with the same tags. If the constraint is None, the frame is delivered to all workers which satisfy the tags.

Example without Tags

Stream	Event 1	Event 2	Event 3	Event 4	Event 5	Event 6
stream 1	all	[1]	[1]	[3]	[3]	[5]
stream 2	all	[2]	[2]	[4]	[4]	[5]
low	all	[1,2]	[]	[3,4]	[]	[5]
slow	all	all	none	none	none	all

• The first frame of all streams is distribute to all workers.
• The next 4 frames of stream 1 are pairwise distributed to the same worker (first 1, then 3).
• Virtual workers 1 and 3 might be the same physical one, but it is not guaranteed
• The last frame of stream 1 and stream 2 are delivered to the same worker
• The second frame of low is deliverd to the same workers which are processing the second frame of stream 1 and stream 2
• The third frame of low is delivered to no workers, i.e. discarded
• The thrid, fourth and fifth event has no frame from slow, this is useful for mixing streams with different sample frequencies.

Trigger map format

The type of a trigger map is

Dict[StreamName, List[Optional[List[VirtualWorker]]]]

This is an example with te generic workers only.

{
    "eiger": [
        [{"tags": ["generic"], "constraint": 2}],
        [{"tags": ["generic"], "constraint": 4}],
        [{"tags": ["generic"], "constraint": 6}],
        [{"tags": ["generic"], "constraint": 8}],
        [{"tags": ["generic"], "constraint": 10}],
        [{"tags": ["generic"], "constraint": 12}],
        [{"tags": ["generic"], "constraint": 14}],
        [{"tags": ["generic"], "constraint": 16}],
        [{"tags": ["generic"], "constraint": 18}]
    ],
    "orca": [
        [{"tags": ["generic"], "constraint": 3}],
        [{"tags": ["generic"], "constraint": 5}],
        [{"tags": ["generic"], "constraint": 7}],
        [{"tags": ["generic"], "constraint": 9}],
        [{"tags": ["generic"], "constraint": 11}],
        [{"tags": ["generic"], "constraint": 13}],
        [{"tags": ["generic"], "constraint": 15}],
        [{"tags": ["generic"], "constraint": 17}],
        [{"tags": ["generic"], "constraint": 19}]
    ],
    "alba": [
        [
            {"tags": ["generic"], "constraint": 2},
            {"tags": ["generic"], "constraint": 3}
        ],
        [
            {"tags": ["generic"], "constraint": 4},
            {"tags": ["generic"], "constraint": 5}
        ],
        [
            {"tags": ["generic"], "constraint": 6},
            {"tags": ["generic"], "constraint": 7}
        ],
        [
            {"tags": ["generic"], "constraint": 8},
            {"tags": ["generic"], "constraint": 9}
        ],
        [
            {"tags": ["generic"], "constraint": 10},
            {"tags": ["generic"], "constraint": 11}
        ],
        [
            {"tags": ["generic"], "constraint": 12},
            {"tags": ["generic"], "constraint": 13}
        ],
        [
            {"tags": ["generic"], "constraint": 14},
            {"tags": ["generic"], "constraint": 15}
        ],
        [
            {"tags": ["generic"], "constraint": 16},
            {"tags": ["generic"], "constraint": 17}
        ],
        [
            {"tags": ["generic"], "constraint": 18},
            {"tags": ["generic"], "constraint": 19}
        ]
    ],
    "slow": [
        null,
        null,
        null,
        [
            {"tags": ["generic"], "constraint": 8},
            {"tags": ["generic"], "constraint": 9}
        ],
        null,
        null,
        null,
        [
            {"tags": ["generic"], "constraint": 16},
            {"tags": ["generic"], "constraint": 17}
        ],
        null
    ]
}