Thread Pool
logic.thread Logic v0.1.0 Queue-fed concurrency frame: consume from the input queue, run the inside body on a pool of threads, publish each result to the output queue.
Finding it in the library
Search the builder's node library for Thread Pool (it lives under Logic). A single click opens the in-editor docs panel shown here — description, ports, and every property, without leaving the canvas. Double-click (or drag) to add it to the workflow.
Library capture pending — regenerate with npm run shots:nodes.
Wired up in the builder
Thread Pool in a real, runnable flow — captured live from the Studio editor, exactly as it looks on your canvas. This is the same workflow used for the example input & output below.
Canvas capture pending — regenerate with npm run shots:nodes.
How it’s configured
The node’s Configure panel as it opens in the builder when you select the step — every setting laid out with real values. Click any field to edit it.
Config capture pending — regenerate with npm run shots:nodes. See the full property reference below.
Ports
Ports are the node’s contract with its neighbours. In the editor a port label renders bold when wired and italic when optional; ◈ ports accept attachment carriers rather than data wires.
| Direction | Port | Label | What flows through it |
|---|---|---|---|
| Input | input | Start | |
| Input | result | Publish | |
| Output | done | Done | |
| Output | message | Message |
How data flows through it
Thread Pool consumes the content of the incoming envelope — when it is fed directly by a trigger, the trigger’s wrapper is unwrapped at the node boundary so the node sees the actual data, not the metadata shell. Its output becomes the payload for the next node, while the envelope (trace ids, correlation, binary refs) rides along untouched. In the Runs view you always see the whole envelope for both sides of this node.
Expressions in the config
String-typed properties accept {{ }} expressions evaluated against the
incoming item at run time — e.g. {{ $json.customer.email }}. On this node
that’s inputQueue, outputQueue, errorQueue, broker, token. JSON- and code-typed fields never interpolate — they are passed through literally.
Build it with AI
Every node in this reference is reachable through Flowdrome’s
AI Copilot and the
MCP tools — say what you want, and the graph surgery
happens server-side. Node types resolve fuzzily, so the catalog label
(Thread Pool) works as well as the exact type id (logic.thread).
In the Copilot panel (or any connected AI):
add a thread pool node after the trigger As a step in a create_chain_workflow call:
{"type":"Thread Pool","config":{}} Raw MCP call — add this node to a workflow with add_node
curl -s -X POST http://localhost:48170/mcp -H "content-type: application/json" -d '{ "jsonrpc": "2.0", "id": "1", "method": "tools/call", "params": { "name": "add_node", "arguments": { "workflowId": "<id>", "type": "Thread Pool" } } }' Example input & output
Captured from a real test run of the workflow above — this is what you see in the run data panel after pressing Test workflow.
On this run the node emitted on port done.
Input — what the node received
{
"kind": "json",
"contentType": "application/json",
"payload": [
{
"v": 1
},
{
"v": 2
},
{
"v": 3
}
],
"body": [
{
"v": 1
},
{
"v": 2
},
{
"v": 3
}
]
} Output — what the node produced
{
"processed": 3,
"failed": 0,
"published": 3,
"seeded": 3,
"threadsPeak": 2,
"initialThreads": 2,
"maxThreads": 4,
"durationMs": 10,
"drained": true,
"inputQueue": "smoke-thr-mrofv57i-in",
"outputQueue": "smoke-thr-mrofv57i-out"
} Property reference
Every setting, with its type and default — the same fields shown configured in the panel above.
| Property | Type | Default | Description |
|---|---|---|---|
Input queueinputQueue | string | "thread-in" | flowdrome.mq queue the pool CONSUMES from (the queue attached on the left). A list arriving on Start is published here first, so wiring data straight in also works. |
Output queueoutputQueue | string | "thread-out" | flowdrome.mq queue every body result is PUBLISHED to (the queue attached on the right). |
Initial threadsinitialThreads | int | 2 | How many threads the pool starts with. |
Max threadsmaxThreads | int | 8 | The pool grows toward this many threads while the input queue is deeper than the live thread count; it never exceeds it. |
Error queueerrorQueue | string | "" | Optional dead-letter queue: a message whose body run fails is published here as { item, error }. Blank = failures are only counted (see the Done summary). |
Max itemsmaxItems | int | 0 | Stop after processing this many messages. 0 = no limit (drain the queue). |
Max duration (ms)maxDurationMs | int | 0 | Stop the pool after this long even if the queue still has messages. 0 = no limit. |
Idle grace (ms)idleGraceMs | int | 0 | How long to keep polling an EMPTY queue before concluding it is drained — lets a producer that is still publishing keep the pool alive. 0 = finish as soon as the queue is empty. |
Broker URLbroker | string | "" | Blank = this engine's own built-in broker. Set another Flowdrome engine's URL to consume/publish across machines. |
Broker tokentoken | string | "" | x-flowdrome-mq-token for a remote broker that requires one. |
Related nodes
The rest of the Logic group — the same folder you’d scan in the editor’s library.
This page is generated from the node registry by gen-node-docs.mjs on every
site build — ports, properties, defaults and visibility rules cannot drift from the code.
The screenshots and example data are captured from a live Flowdrome by
npm run shots:nodes and npm run gen:examples.