Link
Carries a message from one pipeline into another. It lets you keep pipelines small and single-purpose without duplicating the work that feeds them.
Type: link · Category: Common · Ports: one input (egress) · one output (ingress)
When to use it
- One expensive read feeding several independent consumers
- Splitting collection from storage so you can restart one without the other
- Keeping a graph small enough to read on one screen
Settings
| Setting | Key | Purpose |
|---|---|---|
| Mode | mode | egress (send) or ingress (receive). |
| Source nodes | sourceNodeIds | For ingress: which egress links to listen to. |
Example — one collector, two consumers
Pipeline Collect line data:
Inject (30s) → Industrial I/O (read Line1/*) → Link (egress, "line1-readings")
Pipeline Store, and separately pipeline Notify:
Link (ingress ← "line1-readings") → QuestDB (ingress)
Link (ingress ← "line1-readings") → RBE → Send Email
The reading is taken once and delivered to both.
Why bother
Splitting this way means you can stop, edit and restart the notification pipeline without interrupting collection — which you cannot do when both live in one graph. It also means a mistake while editing notifications cannot cost you data.
Gotchas
- A Link only reaches pipelines in its own project. 1.0.8 The project is part of the link's address, so an ingress Link that names an egress Link in another project now hears nothing — and says nothing about it. Before 1.0.8 a Link crossed projects. To pass messages between projects on purpose, use Message Out with Send to: All projects and a Message In on the receiving side; see Message Out.
- Several wires into an egress Link are all sent. A Link fed by two branches broadcasts the message from each of them, not only from the branch that finished last.