Represent queued work on a three-colour desk signal

Status Light has red, amber and green lenses for a software-defined desk signal. A queue introduces a state that is easy to overlook: work exists, but execution has not started. Decide whether that distinction matters to your workflow before assigning colours. A queue waiting normally is different from a worker that has stopped making progress.

What does the queue state actually measure?

Identify whether the source reports accepted work, scheduled work or items ready for a worker. Those stages can have different meanings. An empty worker process does not establish an empty upstream queue, and a submitted request does not prove it was accepted.

Use the source's documented identifiers and states to track the items that belong to your desk view. If you only observe a local queue, label the scope accordingly. Avoid making the lamp appear to represent an entire service when it covers one small processing stage.

How should waiting differ from running?

Choose a convention that lets you tell whether work has begun when that is useful. With limited physical states, you may decide to use the lamp for attention and a text view for the exact queued or running label. There is no need to invent unsupported display effects to force every detail into the hardware.

If you assign the same colour to both states, explain that it means work outstanding rather than actively executing. Clear wording can make a simple signal honest. Ambiguous wording can make the same signal misleading even when the integration is technically consistent.

What happens when queued and running items coexist?

Define an aggregation rule for the selected workload. For example, a running item may take precedence in the physical summary while a companion view shows remaining queued work. An unresolved error may need higher priority than either. Choose based on the action you want the signal to prompt.

Do not let a queue-count update overwrite a failure merely because it arrived later. Store the relevant task and queue facts separately, then calculate the summary. Keep freshness visible so an old queue count does not masquerade as a current view of available work.

How do you distinguish delay from a stuck queue?

Compare waiting time with the source's expected behaviour and any worker-health evidence you can actually observe. A busy system can legitimately queue work. Use a documented attention threshold appropriate to your workflow rather than treating any wait as failure.

Test an empty queue, queued-only work, active processing and a stopped worker with items remaining. The Status Light hardware details describe the physical indicator; queue semantics, priorities and delay detection must come from the integration and its authoritative sources.