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packages/plugos/hooks/node_cron.ts

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+import { Hook, Manifest } from "../types";
+import cron, { ScheduledTask } from "node-cron";
+import { safeRun } from "../util";
+import { System } from "../system";
+
+export type CronHookT = {
+  cron?: string | string[];
+};
+
+export class NodeCronHook implements Hook<CronHookT> {
+  apply(system: System<CronHookT>): void {
+    let tasks: ScheduledTask[] = [];
+    system.on({
+      plugLoaded: (name, plug) => {
+        reloadCrons();
+      },
+      plugUnloaded(name, plug) {
+        reloadCrons();
+      },
+    });
+
+    reloadCrons();
+
+    function reloadCrons() {
+      tasks.forEach((task) => task.stop());
+      tasks = [];
+      for (let plug of system.loadedPlugs.values()) {
+        if (!plug.manifest) {
+          continue;
+        }
+        for (const [name, functionDef] of Object.entries(
+          plug.manifest.functions
+        )) {
+          if (!functionDef.cron) {
+            continue;
+          }
+          const crons = Array.isArray(functionDef.cron)
+            ? functionDef.cron
+            : [functionDef.cron];
+          for (let cronDef of crons) {
+            tasks.push(
+              cron.schedule(cronDef, () => {
+                console.log("Now acting on cron", cronDef);
+                safeRun(async () => {
+                  try {
+                    await plug.invoke(name, [cronDef]);
+                  } catch (e: any) {
+                    console.error("Execution of cron function failed", e);
+                  }
+                });
+              })
+            );
+          }
+        }
+      }
+    }
+  }
+
+  validateManifest(manifest: Manifest<CronHookT>): string[] {
+    let errors = [];
+    for (const [name, functionDef] of Object.entries(manifest.functions)) {
+      if (!functionDef.cron) {
+        continue;
+      }
+      const crons = Array.isArray(functionDef.cron)
+        ? functionDef.cron
+        : [functionDef.cron];
+      for (let cronDef of crons) {
+        if (!cron.validate(cronDef)) {
+          errors.push(`Invalid cron expression ${cronDef}`);
+        }
+      }
+    }
+    return errors;
+  }
+}