refactor: de-duplicate channel runtime and payload helpers

src/plugin-sdk/runtime.ts

@@ -0,0 +1,24 @@
+import { format } from "node:util";
+import type { RuntimeEnv } from "../runtime.js";
+
+type LoggerLike = {
+  info: (message: string) => void;
+  error: (message: string) => void;
+};
+
+export function createLoggerBackedRuntime(params: {
+  logger: LoggerLike;
+  exitError?: (code: number) => Error;
+}): RuntimeEnv {
+  return {
+    log: (...args) => {
+      params.logger.info(format(...args));
+    },
+    error: (...args) => {
+      params.logger.error(format(...args));
+    },
+    exit: (code: number): never => {
+      throw params.exitError?.(code) ?? new Error(`exit ${code}`);
+    },
+  };
+}