Nodes & @Rewire

Nodes are pre-registered Swift or Kotlin functions that PipeKit can execute remotely in production. They are the atomic units of runtime control.

What is a Node?

A node is a function annotated with @Rewire that registers itself with PipeKit at app launch. Once registered, the node can be triggered remotely — individually or as part of a flow — without shipping an update.

Nodes are deterministic by design. Only functions declared at build time can execute. There is no arbitrary code injection, no eval, no dynamic payloads that run as code. This is what makes PipeKit safe for production.

Registering a Node

Use the @Rewire macro to register a function as a remotely executable node.

import PipeKit

@FlowEntry
class CacheNode {
    @Rewire("clear-cache")
    static func clearCache() async throws -> [String: Any] {
        let freed = await CacheManager.shared.purge()
        return ["freed": "\(freed)MB"]
    }
}

Nodes with Parameters

Nodes can accept typed parameters. These are passed from the flow definition or provided at execution time via the dashboard or API.

import PipeKit

@FlowEntry
class FeatureToggle {
    @Rewire("toggle-feature")
    static func toggleFeature(name: String, enabled: Bool) async throws -> [String: Any] {
        FeatureFlags.set(name, enabled)
        return ["feature": name, "enabled": "\(enabled)"]
    }

    @Rewire("set-log-level")
    static func setLogLevel(level: String) async throws -> [String: Any] {
        guard let logLevel = AppLogLevel(rawValue: level) else {
            throw NSError(domain: "app", code: 1,
                userInfo: [NSLocalizedDescriptionKey: "Invalid log level: \(level)"])
        }
        Logger.shared.level = logLevel
        return ["level": level]
    }
}

Node Results & Failure

A node simply returns a value — a dictionary ([String: Any] /Map<String, Any>), a Bool,Double,String, etc. That return value becomes the node's output: it's recorded in the execution log and auto-wired into the next node's matching inputs. To fail a node, throw.

Node Catalog

When a device connects to PipeKit, the SDK reports all registered nodes to the server. These appear in the Nodes section of the dashboard, where you can see each node's identifier, parameter schema, and which devices have it registered.

Nodes are scoped to your app's bundle ID. Different apps maintain independent node catalogs.

Best Practices