saving

ts/packages/base/src/processor/flow-processor.ts

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+/**
+ * Flow-aware processor that manages dynamic flow instances.
+ *
+ * Python reference: trustgraph-base/trustgraph/base/flow_processor.py
+ */
+
+import { AsyncProcessor, type ProcessorConfig } from "./async-processor.js";
+import type { Spec } from "../spec/types.js";
+import { Flow, type FlowDefinition } from "./flow.js";
+
+export abstract class FlowProcessor extends AsyncProcessor {
+  private specifications: Spec[] = [];
+  private flows = new Map<string, Flow>();
+
+  constructor(config: ProcessorConfig) {
+    super(config);
+    this.registerConfigHandler(this.onConfigureFlows.bind(this));
+  }
+
+  registerSpecification(spec: Spec): void {
+    this.specifications.push(spec);
+  }
+
+  protected async run(): Promise<void> {
+    // The processor sits idle waiting for flow configurations
+    // to arrive via the config push topic. In the meantime,
+    // the consumer loop runs in the background.
+    await new Promise<void>((resolve) => {
+      const check = () => {
+        if (!this.running) resolve();
+        else setTimeout(check, 1000);
+      };
+      check();
+    });
+  }
+
+  private async onConfigureFlows(
+    config: Record<string, unknown>,
+    version: number,
+  ): Promise<void> {
+    const flowDefs = config.flows as Record<string, FlowDefinition> | undefined;
+    if (!flowDefs) return;
+
+    // Stop removed flows
+    for (const [name, flow] of this.flows) {
+      if (!(name in flowDefs)) {
+        await flow.stop();
+        this.flows.delete(name);
+      }
+    }
+
+    // Start new flows
+    for (const [name, defn] of Object.entries(flowDefs)) {
+      if (!this.flows.has(name)) {
+        const flow = new Flow(name, this.config.id, this.pubsub, defn, this.specifications);
+        await flow.start();
+        this.flows.set(name, flow);
+      }
+    }
+  }
+
+  override async stop(): Promise<void> {
+    for (const flow of this.flows.values()) {
+      await flow.stop();
+    }
+    this.flows.clear();
+    await super.stop();
+  }
+}