chore: centeralize @temporalio/workflow loading

Author: chris-olszewski

packages/interceptors-opentelemetry/src/workflow/context-manager.ts

@@ -1,24 +1,15 @@
 import * as otel from '@opentelemetry/api';
-import type { AsyncLocalStorage as AsyncLocalStorageType } from '@temporalio/workflow';
+import { ensureWorkflowModuleLoaded, getWorkflowModuleIfAvailable } from './workflow-module-loader';
 
-// @temporalio/workflow is an optional peer dependency.
-// It can be missing as long as the user isn't attempting to construct a workflow interceptor.
-let AsyncLocalStorage: typeof AsyncLocalStorageType | undefined;
-let workflowModuleLoadError: any | undefined;
-try {
-  AsyncLocalStorage = require('@temporalio/workflow').AsyncLocalStorage;
-} catch (err) {
-  // Capture the module not found error to rethrow if an interceptor is constructed
-  workflowModuleLoadError = err;
-}
+const AsyncLocalStorage = getWorkflowModuleIfAvailable()?.AsyncLocalStorage;
 
 export class ContextManager implements otel.ContextManager {
+  // If `@temporalio/workflow` is not available, ignore for now.
+  // When ContextManager is constructed module resolution error will be thrown.
   protected storage = AsyncLocalStorage ? new AsyncLocalStorage<otel.Context>() : undefined;
 
   public constructor() {
-    if (workflowModuleLoadError) {
-      throw workflowModuleLoadError;
-    }
+    ensureWorkflowModuleLoaded();
   }
 
   active(): otel.Context {

packages/interceptors-opentelemetry/src/workflow/index.ts

@@ -22,20 +22,7 @@ import { instrument, extractContextFromHeaders, headersWithContext } from '../in
 import { ContextManager } from './context-manager';
 import { SpanName, SPAN_DELIMITER } from './definitions';
 import { SpanExporter } from './span-exporter';
-import type * as WorkflowModule from '@temporalio/workflow';
-
-// @temporalio/workflow is an optional peer dependency.
-// It can be missing as long as the user isn't attempting to construct a workflow interceptor.
-// If we start shipping ES modules alongside CJS, we will have to reconsider
-// this dynamic import as `import` is async for ES modules.
-let workflowModule: typeof WorkflowModule | undefined;
-let workflowModuleLoadError: any | undefined;
-try {
-  workflowModule = require('@temporalio/workflow');
-} catch (err) {
-  // Capture the module not found error to rethrow if an interceptor is constructed
-  workflowModuleLoadError = err;
-}
+import { ensureWorkflowModuleLoaded, getWorkflowModule } from './workflow-module-loader';
 
 export * from './definitions';
 
@@ -65,17 +52,14 @@ export class OpenTelemetryInboundInterceptor implements WorkflowInboundCallsInte
   protected readonly tracer = getTracer();
 
   public constructor() {
-    if (workflowModuleLoadError) {
-      throw workflowModuleLoadError;
-    }
+    ensureWorkflowModuleLoaded();
   }
 
   public async execute(
     input: WorkflowExecuteInput,
     next: Next<WorkflowInboundCallsInterceptor, 'execute'>
   ): Promise<unknown> {
-    // workflowModule will be defined as module load error is checked in the constructor
-    const { workflowInfo, ContinueAsNew } = workflowModule!;
+    const { workflowInfo, ContinueAsNew } = getWorkflowModule();
     const context = await extractContextFromHeaders(input.headers);
     return await instrument({
       tracer: this.tracer,
@@ -109,9 +93,7 @@ export class OpenTelemetryOutboundInterceptor implements WorkflowOutboundCallsIn
   protected readonly tracer = getTracer();
 
   public constructor() {
-    if (workflowModuleLoadError) {
-      throw workflowModuleLoadError;
-    }
+    ensureWorkflowModuleLoaded();
   }
 
   public async scheduleActivity(
@@ -169,8 +151,7 @@ export class OpenTelemetryOutboundInterceptor implements WorkflowOutboundCallsIn
     input: ContinueAsNewInput,
     next: Next<WorkflowOutboundCallsInterceptor, 'continueAsNew'>
   ): Promise<never> {
-    // workflowModule will be defined as module load error is checked in the constructor
-    const { ContinueAsNew } = workflowModule!;
+    const { ContinueAsNew } = getWorkflowModule();
     return await instrument({
       tracer: this.tracer,
       spanName: `${SpanName.CONTINUE_AS_NEW}${SPAN_DELIMITER}${input.options.workflowType}`,

packages/interceptors-opentelemetry/src/workflow/runtime.ts

@@ -2,18 +2,11 @@
  * Sets global variables required for importing opentelemetry in isolate
  * @module
  */
-import type { inWorkflowContext as InWorkflowContext } from '@temporalio/workflow';
+import { getWorkflowModuleIfAvailable } from './workflow-module-loader';
 
-// @temporalio/workflow is an optional peer dependency and might not be available.
-// If it is not available, we can assume that we are not in a workflow context.
-let inWorkflowContext: typeof InWorkflowContext | undefined;
-try {
-  inWorkflowContext = require('@temporalio/workflow').inWorkflowContext;
-} catch (_) {
-  inWorkflowContext = undefined;
-}
+const inWorkflowContext = getWorkflowModuleIfAvailable()?.inWorkflowContext;
 
-if (inWorkflowContext && inWorkflowContext()) {
+if (inWorkflowContext?.()) {
   // Required by opentelemetry (pretend to be a browser)
   Object.assign(globalThis, {
     performance: {

packages/interceptors-opentelemetry/src/workflow/span-exporter.ts

@@ -1,29 +1,13 @@
 import * as tracing from '@opentelemetry/sdk-trace-base';
 import { ExportResult, ExportResultCode } from '@opentelemetry/core';
 import { OpenTelemetrySinks, SerializableSpan } from './definitions';
+import { ensureWorkflowModuleLoaded, getWorkflowModuleIfAvailable } from './workflow-module-loader';
 
-import type * as WorkflowModule from '@temporalio/workflow';
-
-// @temporalio/workflow is an optional peer dependency.
-// It can be missing as long as the user isn't attempting to construct a workflow interceptor.
-// If we start shipping ES modules alongside CJS, we will have to reconsider
-// this dynamic import as `import` is async for ES modules.
-let wf: typeof WorkflowModule | undefined;
-let workflowModuleLoadError: any | undefined;
-try {
-  wf = require('@temporalio/workflow');
-} catch (err) {
-  // Capture the module not found error to rethrow if an interceptor is constructed
-  workflowModuleLoadError = err;
-}
-
-const exporter = wf?.proxySinks<OpenTelemetrySinks>()?.exporter;
+const exporter = getWorkflowModuleIfAvailable()?.proxySinks<OpenTelemetrySinks>()?.exporter;
 
 export class SpanExporter implements tracing.SpanExporter {
   public constructor() {
-    if (workflowModuleLoadError) {
-      throw workflowModuleLoadError;
-    }
+    ensureWorkflowModuleLoaded();
   }
 
   public export(spans: tracing.ReadableSpan[], resultCallback: (result: ExportResult) => void): void {

packages/interceptors-opentelemetry/src/workflow/workflow-module-loader.ts

@@ -0,0 +1,46 @@
+/**
+ * Utilities for working with a possibly missing `@temporalio/workflow` peer dependency
+ * @module
+ */
+import type * as WorkflowModule from '@temporalio/workflow';
+
+// @temporalio/workflow is an optional peer dependency.
+// It can be missing as long as the user isn't attempting to construct a workflow interceptor.
+// If we start shipping ES modules alongside CJS, we will have to reconsider
+// this dynamic import as `import` is async for ES modules.
+let workflowModule: typeof WorkflowModule | undefined;
+let workflowModuleLoadError: any | undefined;
+
+try {
+  workflowModule = require('@temporalio/workflow');
+} catch (err) {
+  // Capture the module not found error to rethrow if the module is required
+  workflowModuleLoadError = err;
+}
+
+/**
+ * Returns `@temporalio/workflow` module if present.
+ * Throws if the module failed to load
+ */
+export function getWorkflowModule(): typeof WorkflowModule {
+  if (workflowModuleLoadError) {
+    throw workflowModuleLoadError;
+  }
+  return workflowModule!;
+}
+
+/**
+ * Checks if the workflow module loaded successfully and throws if not.
+ */
+export function ensureWorkflowModuleLoaded(): void {
+  if (workflowModuleLoadError) {
+    throw workflowModuleLoadError;
+  }
+}
+
+/**
+ * Returns the workflow module if available, or undefined if it failed to load.
+ */
+export function getWorkflowModuleIfAvailable(): typeof WorkflowModule | undefined {
+  return workflowModule;
+}