Pipelines

A pipeline is a directed graph of nodes that moves and transforms data. Where the namespace answers "what is this value?", a pipeline answers "what should happen to it?"

One trigger, one read, one calculation, two destinations.

When to use a pipeline

Situation	Use
Show a live value on a screen	A binding — no pipeline needed
React to a button press on a screen	An event action
Move data on a schedule or an event, reliably	A pipeline
Transform, enrich, aggregate before storing	A pipeline
Expose an HTTP endpoint other systems call	A pipeline (REST ingress)
Bridge one protocol to another	A pipeline, or a second binding for simple cases
Server-side logic invoked from a screen	A Gateway script

The distinguishing property of a pipeline is reliability: writes it performs are covered by store-and-forward — buffered on outage, replayed in order, quarantined on permanent failure. A script write is immediate and fails to its caller.

Anatomy

Concept	Meaning
Node	One step. Has a type, a configuration, optional code, and input/output ports.
Connection (wire)	Passes a message from one node's output to another's input.
Message	The envelope travelling the graph: a payload plus metadata and context.
Trigger	What starts execution — a schedule, an inbound HTTP request, a tag change, a message on the bus, a manual run.
Execution	One traversal of the graph, logged and inspectable.

The message

Every node receives a message and returns one. In scripts you see two things:

Name	Contents
payload	The primary data — what the previous node produced.
message	The full envelope: payload plus metadata, correlation identifiers and context.

def transform(payload, message):
    # payload — the data
    # message — the envelope, including where it came from
    return {"value": payload["value"] * 2}

Return the value you want the next node to receive.

Node categories

Category	Nodes
Common	Inject, Link, RBE (Filter), Switch, Timer
Realtime	Industrial I/O, Alarm
Datasource	SQL Query, MongoDB, QuestDB
Transform	Python Script, Batch Transform, Array Iterator, Join
AI	AI
Notification	Send Email, Telegram, WhatsApp, On-Call Roster
API	REST API, HTTP Response
Message Bus 1.0.8	Message In, Message Out, Message Reply
Output	Debug, Catch

→ Node reference for every node's configuration.

Execution model

• Execution is graph-driven, not line-by-line: a node runs when a message arrives on its input.
• A node with several outbound wires fans out — every downstream branch receives the message.
• Switch is the exception: it has one output per rule, and a message leaves by the outputs whose rules matched. A branch that did not fire is skipped, and the skip cascades.
• Array Iterator splits an array into one message per item; Join collects them back.
• Batch Transform processes items of a collection in parallel.
• Timer is the only node that defers. It never blocks the graph: it hands a deadline to the runtime and returns, and the run that fires later is an independent one — which is how a repeating timer works in a graph that forbids cycles.
• Errors are logged against the execution, and the branch stops. Other branches continue.

→ Execution and triggering

Pipeline lifecycle

State	Meaning
Stopped	Not listening, not scheduled.
Running	Triggers are armed; the graph executes when they fire.
Error	Started but a node failed fatally; see the execution log.

Action	Permission
Start or stop a pipeline, or all of them	Start/Stop Pipeline
Execute once, now	Execute Pipeline
Trigger a single node	Execute Pipeline
See runtime state	authenticated

A pipeline is also enabled/disabled as configuration. Disabling stops it and keeps it from being started by "start all" — the right way to shelve a pipeline without deleting it.

The canvas

Control	Does	Shortcut
Undo / Redo	Step back and forward through your edits	⌘/Ctrl+Z · ⌘/Ctrl+Shift+Z
Zoom out / Zoom in		Ctrl/⌘ + scroll
The zoom percentage	Click it to reset to 100%
Zoom to fit	Frame the whole graph

New in 1.0.4 — the controls are on the canvas itself, and undo and redo grey out when there is nothing to step to, so the canvas says what is available rather than leaving you to try it.

Multi-touch pinch to zoom and two-finger pan work on a touch screen. New in 1.0.1

Editing safely

Pipelines are optimistically locked with a server-managed revision. Saving carries the revision you loaded; a concurrent save by someone else is rejected rather than silently overwriting. Two engineers editing the same pipeline get a conflict to resolve, not a lost afternoon.

Cross-pipeline communication

Mechanism	Use
Link nodes	Send messages between pipelines of the same project without wiring them into one graph.
Message bus 1.0.8	Send by subject to any pipeline, screen or script that listens — and ask for a reply. Message In, Message Out, Message Reply.
Variables	Shared key/value state readable and writable from any pipeline or script.
Tags	The most decoupled option — one pipeline writes an internal tag, another subscribes.

→ Message bus · Variables

Link or message bus? A Link joins two of your pipelines by node: the receiver names the sender, and nothing else can hear it. The bus joins anything to anything by subject: the sender does not know who listens, a screen's button or a script can send too, and a request gets an answer back. Reach for a Link for a fixed hand-off; reach for the bus when the receiver should be replaceable or the sender is not a pipeline.

A Link no longer crosses projects

Changed in 1.0.8 The project is now part of a Link's address. An ingress Link listening to an egress Link in another project stops receiving after the upgrade, without an error. Replace such a pair with Message Out (Send to: All projects) and Message In.

Observability

What	Where
Per-execution log	The execution log panel (needs View Execution Logs)
Per-node results	The execution log panel, per node (needs View Execution Logs)
Live node status	Node badges on the canvas, pushed over the telemetry bus
Whether a node's connection is up	The status line under the node — see below
Ad-hoc inspection	The Debug node → the Debug panel

Clearing logs requires Clear Execution Logs; they are diagnostic data, not the audit journal.

The connection status under a node New in 1.0.7

Every node that names a connection — an Industrial I/O read, a SQL Query, a Telegram receiver — carries a small square and a few words under the card, saying whether that connection is up. Before, a node told you which connection it used and nothing about its state, so a pipeline full of nodes bound to a dead device looked exactly like one that was working. That is worst for a trigger node: one whose connection is down and one that simply has not been sent anything are both blank.

The two indicators answer different questions. The round badge in the node's corner is the last run — running, succeeded, failed. The square underneath is the connection behind it, and it changes whether or not the pipeline runs.

Changed in 1.0.8 The exception is a notification node — Send Email, Telegram, WhatsApp. Its line answers "is this node sending or receiving right now?", which has an answer only while the pipeline runs, so it is shown only then. On a stopped pipeline it kept reading receiving · 12 in from the bot's last state, which looked like the stopped node was still live. A database or device node keeps its line at design time: seeing that connection is down before you press Start is the point.

Square	Caption	Means
Green	connected	The connection is up. Only this status ever says connected.
Green	receiving · 12 in · 5 out	Up and traffic is flowing — the counts are what prove the node has done something.
Green	connected · waiting	Up, and nothing has arrived yet.
Amber	checking…	A check is in progress and has not answered.
Amber	retrying	Lost, and reconnecting.
Yellow	no recent data	Nothing heard for longer than expected — not yet a failure, and deliberately not connected.
Orange	backing off	Failing repeatedly, so attempts are paused for a while.
Red	error, or a specific failure	Failed. Hover for the full message.
Grey	disabled	The connection is switched off, and a node using it will fail.
Grey	not checked	Nobody has asked it anything yet — a new connection has not failed.

The caption is the glance; the full sentence is in the tooltip. For a Telegram bot the red case not polling is told apart from a plain error, because it has its own fix: enable the bot. 1.0.8 The captions token in use elsewhere and updates not arriving are gone — both fired on a healthy bot, during its own restart, and made it flicker between connected and failed. → Telegram status

The status is the same one the Connections list shows, and every node bound to one connection shares it, so a canvas with eighty nodes on four connections costs four subscriptions, not eighty.

Permissions

Action	Permission
View pipelines	View Pipelines
Create	Create Pipeline
Edit	Edit Pipeline
Delete	Delete Pipeline
Execute once	Execute Pipeline
Start/stop	Start/Stop Pipeline
Export	Export Pipeline
Import	Import Pipeline
View execution logs	View Execution Logs
Clear execution logs	Clear Execution Logs

In this section

Page	Contents
Node reference	Every node type and its configuration
Execution & triggering	How and when a pipeline runs, and how to debug it
Variables	Shared state across pipelines and scripts
REST endpoints	Publishing HTTP APIs from a pipeline