feat(sdk): aws.Function.context() for lambda functions (#6424)

Closes #6412

## Checklist

- [x] Title matches [Winglang's style guide](https://www.winglang.io/contributing/start-here/pull_requests#how-are-pull-request-titles-formatted)
- [x] Description explains motivation and solution
- [x] Tests added (always)
- [ ] Docs updated (only required for features)
- [ ] Added `pr/e2e-full` label if this feature requires end-to-end testing

*By submitting this pull request, I confirm that my contribution is made under the terms of the [Wing Cloud Contribution License](https://github.com/winglang/wing/blob/main/CONTRIBUTION_LICENSE.md)*.

docs/docs/04-standard-library/aws/api-reference.md

@@ -1053,10 +1053,23 @@ new aws.Function();
 
 | **Name** | **Description** |
 | --- | --- |
+| <code><a href="#@winglang/sdk.aws.Function.context">context</a></code> | Returns the current Lambda invocation context, if the host is an AWS Lambda. |
 | <code><a href="#@winglang/sdk.aws.Function.from">from</a></code> | If the inflight host is an AWS Lambda, return a helper interface for working with it. |
 
 ---
 
+##### `context` <a name="context" id="@winglang/sdk.aws.Function.context"></a>
+
+```wing
+bring aws;
+
+aws.Function.context();
+```
+
+Returns the current Lambda invocation context, if the host is an AWS Lambda.
+
+> [https://docs.aws.amazon.com/lambda/latest/dg/nodejs-prog-model-context.html](https://docs.aws.amazon.com/lambda/latest/dg/nodejs-prog-model-context.html)
+
 ##### `from` <a name="from" id="@winglang/sdk.aws.Function.from"></a>
 
 ```wing
@@ -2001,6 +2014,128 @@ AWS Bucket name.
 
 ---
 
+### ILambdaContext <a name="ILambdaContext" id="@winglang/sdk.aws.ILambdaContext"></a>
+
+- *Implemented By:* <a href="#@winglang/sdk.aws.ILambdaContext">ILambdaContext</a>
+
+The AWS Lambda context object.
+
+#### Methods <a name="Methods" id="Methods"></a>
+
+| **Name** | **Description** |
+| --- | --- |
+| <code><a href="#@winglang/sdk.aws.ILambdaContext.remainingTimeInMillis">remainingTimeInMillis</a></code> | Returns the number of milliseconds left before the execution times out. |
+
+---
+
+##### `remainingTimeInMillis` <a name="remainingTimeInMillis" id="@winglang/sdk.aws.ILambdaContext.remainingTimeInMillis"></a>
+
+```wing
+remainingTimeInMillis(): num
+```
+
+Returns the number of milliseconds left before the execution times out.
+
+#### Properties <a name="Properties" id="Properties"></a>
+
+| **Name** | **Type** | **Description** |
+| --- | --- | --- |
+| <code><a href="#@winglang/sdk.aws.ILambdaContext.property.awsRequestId">awsRequestId</a></code> | <code>str</code> | The identifier of the invocation request. |
+| <code><a href="#@winglang/sdk.aws.ILambdaContext.property.functionName">functionName</a></code> | <code>str</code> | The name of the Lambda function. |
+| <code><a href="#@winglang/sdk.aws.ILambdaContext.property.functionVersion">functionVersion</a></code> | <code>str</code> | The version of the function. |
+| <code><a href="#@winglang/sdk.aws.ILambdaContext.property.invokedFunctionArn">invokedFunctionArn</a></code> | <code>str</code> | The Amazon Resource Name (ARN) that's used to invoke the function. |
+| <code><a href="#@winglang/sdk.aws.ILambdaContext.property.logGroupName">logGroupName</a></code> | <code>str</code> | The log group for the function. |
+| <code><a href="#@winglang/sdk.aws.ILambdaContext.property.logStreamName">logStreamName</a></code> | <code>str</code> | The log stream for the function instance. |
+| <code><a href="#@winglang/sdk.aws.ILambdaContext.property.memoryLimitInMB">memoryLimitInMB</a></code> | <code>str</code> | The amount of memory that's allocated for the function. |
+
+---
+
+##### `awsRequestId`<sup>Required</sup> <a name="awsRequestId" id="@winglang/sdk.aws.ILambdaContext.property.awsRequestId"></a>
+
+```wing
+awsRequestId: str;
+```
+
+- *Type:* str
+
+The identifier of the invocation request.
+
+---
+
+##### `functionName`<sup>Required</sup> <a name="functionName" id="@winglang/sdk.aws.ILambdaContext.property.functionName"></a>
+
+```wing
+functionName: str;
+```
+
+- *Type:* str
+
+The name of the Lambda function.
+
+---
+
+##### `functionVersion`<sup>Required</sup> <a name="functionVersion" id="@winglang/sdk.aws.ILambdaContext.property.functionVersion"></a>
+
+```wing
+functionVersion: str;
+```
+
+- *Type:* str
+
+The version of the function.
+
+---
+
+##### `invokedFunctionArn`<sup>Required</sup> <a name="invokedFunctionArn" id="@winglang/sdk.aws.ILambdaContext.property.invokedFunctionArn"></a>
+
+```wing
+invokedFunctionArn: str;
+```
+
+- *Type:* str
+
+The Amazon Resource Name (ARN) that's used to invoke the function.
+
+Indicates if the invoker specified a version number or alias.
+
+---
+
+##### `logGroupName`<sup>Required</sup> <a name="logGroupName" id="@winglang/sdk.aws.ILambdaContext.property.logGroupName"></a>
+
+```wing
+logGroupName: str;
+```
+
+- *Type:* str
+
+The log group for the function.
+
+---
+
+##### `logStreamName`<sup>Required</sup> <a name="logStreamName" id="@winglang/sdk.aws.ILambdaContext.property.logStreamName"></a>
+
+```wing
+logStreamName: str;
+```
+
+- *Type:* str
+
+The log stream for the function instance.
+
+---
+
+##### `memoryLimitInMB`<sup>Required</sup> <a name="memoryLimitInMB" id="@winglang/sdk.aws.ILambdaContext.property.memoryLimitInMB"></a>
+
+```wing
+memoryLimitInMB: str;
+```
+
+- *Type:* str
+
+The amount of memory that's allocated for the function.
+
+---
+
 ## Enums <a name="Enums" id="Enums"></a>
 
 ### Effect <a name="Effect" id="@winglang/sdk.aws.Effect"></a>

docs/docs/04-standard-library/cloud/function.md

@@ -127,6 +127,25 @@ if let lambdaFn = aws.Function.from(f) {
 }
 ```
 
+To access the AWS Lambda context object, you can use the `aws.Function` class as shown below.
+
+```ts playground
+bring aws;
+bring cloud;
+
+let f = new cloud.Function(inflight () => {
+ if let ctx = aws.Function.context() {
+ log(ctx.logGroupName); // prints the log group name
+ log(ctx.logStreamName); // prints the log stream name
+
+ let remainingTime = ctx.remainingTimeInMillis();
+ assert(remainingTime > 0);
+ }
+});
+```
+
+The `context()` method returns `nil` when ran on non-AWS targets.
+
 ### Azure (`tf-azure`)
 
 The Azure implementation of `cloud.Function` uses [Azure Functions](https://azure.microsoft.com/en-us/products/functions).

examples/tests/sdk_tests/function/aws-function.test.w

@@ -1,5 +1,6 @@
-bring cloud;
 bring aws;
+bring cloud;
+bring expect;
 bring util;
 
 let target = util.env("WING_TARGET");
@@ -35,4 +36,40 @@ test "validates the AWS Function" {
  // If the test is not on AWS, it should not fail, so I am returning true.
  assert(true);
  }
-}
+}
+
+let fn = new cloud.Function(inflight (msg: str?) => {
+ if msg == "error" {
+ throw "fake error";
+ }
+
+ if let ctx = aws.Function.context() {
+ log(Json.stringify(ctx));
+ expect.equal(ctx.functionVersion, "$LATEST");
+
+ let remainingTime = ctx.remainingTimeInMillis();
+ assert(remainingTime > 0);
+ } else {
+ if target == "tf-aws" || target == "awscdk" {
+ expect.fail("Expected to have a context object");
+ }
+ }
+
+ return msg;
+}) as "FunctionAccessingContext";
+
+test "can access lambda context" {
+ let result = fn.invoke("hello");
+ expect.equal(result, "hello");
+
+ let result2 = fn.invoke("hello2");
+ expect.equal(result2, "hello2");
+
+ let var msg = "";
+ try {
+ fn.invoke("error");
+ } catch err {
+ msg = err;
+ }
+ expect.ok(msg.contains("fake error"), "Expected fake error message");
+}

libs/awscdk/src/function.ts

@@ -12,7 +12,13 @@ import { Construct, IConstruct } from "constructs";
 import { cloud, std, core } from "@winglang/sdk";
 import { NotImplementedError } from "@winglang/sdk/lib/core/errors";
 import { createBundle } from "@winglang/sdk/lib/shared/bundling";
-import { IAwsFunction, NetworkConfig, PolicyStatement, externalLibraries } from "@winglang/sdk/lib/shared-aws";
+import {
+ IAwsFunction,
+ NetworkConfig,
+ PolicyStatement,
+ externalLibraries,
+} from "@winglang/sdk/lib/shared-aws";
+import { makeAwsLambdaHandler } from "@winglang/sdk/lib/shared-aws/function-util";
 import { resolve } from "path";
 import { renameSync, rmSync, writeFileSync } from "fs";
 import { App } from "./app";
@@ -201,7 +207,9 @@ export class Function
 
  public addNetwork(config: NetworkConfig): void {
  config;
- throw new Error("The AWS CDK platform provider does not support adding network configurations to AWS Lambda functions at the moment.");
+ throw new Error(
+ "The AWS CDK platform provider does not support adding network configurations to AWS Lambda functions at the moment."
+ );
  }
 
  private envName(): string {
@@ -219,4 +227,11 @@ export class Function
  public get functionName(): string {
  return this.function.functionName;
  }
+
+ /**
+ * @internal
+ */
+ protected _getCodeLines(handler: cloud.IFunctionHandler): string[] {
+ return makeAwsLambdaHandler(handler);
+ }
 }

libs/wingc/src/type_check/jsii_importer.rs

@@ -583,9 +583,6 @@ impl<'a> JsiiImporter<'a> {
  if let Some(properties) = jsii_interface.properties() {
  for p in properties {
  debug!("Found property {} with type {:?}", p.name.green(), p.type_);
- if member_phase == Phase::Inflight {
- todo!("No support for inflight properties yet");
- }
  let base_wing_type = self.type_ref_to_wing_type(&p.type_);
  let is_optional = if let Some(true) = p.optional { true } else { false };
  let is_static = if let Some(true) = p.static_ { true } else { false };

libs/wingsdk/src/cloud/function.md

@@ -127,6 +127,25 @@ if let lambdaFn = aws.Function.from(f) {
 }
 ```
 
+To access the AWS Lambda context object, you can use the `aws.Function` class as shown below.
+
+```ts playground
+bring aws;
+bring cloud;
+
+let f = new cloud.Function(inflight () => {
+ if let ctx = aws.Function.context() {
+ log(ctx.logGroupName); // prints the log group name
+ log(ctx.logStreamName); // prints the log stream name
+
+ let remainingTime = ctx.remainingTimeInMillis();
+ assert(remainingTime > 0);
+ }
+});
+```
+
+The `context()` method returns `nil` when ran on non-AWS targets.
+
 ### Azure (`tf-azure`)
 
 The Azure implementation of `cloud.Function` uses [Azure Functions](https://azure.microsoft.com/en-us/products/functions).

libs/wingsdk/src/expect/index.ts

@@ -1 +1 @@
-export * from "./assert";
+export * from "./expect";

libs/wingsdk/src/shared-aws/function-util.ts

@@ -0,0 +1,34 @@
+import * as cloud from "../cloud";
+
+export function makeAwsLambdaHandler(
+ handler: cloud.IFunctionHandler
+): string[] {
+ const inflightClient = handler._toInflight();
+ const lines = new Array<string>();
+ const client = "$handler";
+
+ lines.push('"use strict";');
+ lines.push(`var ${client} = undefined;`);
+ lines.push("exports.handler = async function(event, context) {");
+ lines.push(" try {");
+ lines.push(" if (globalThis.$awsLambdaContext === undefined) {");
+ lines.push(" globalThis.$awsLambdaContext = context;");
+ lines.push(` ${client} = ${client} ?? (${inflightClient});`);
+ lines.push(" } else {");
+ lines.push(" throw new Error(");
+ lines.push(" 'An AWS Lambda context object was already defined.'");
+ lines.push(" );");
+ lines.push(" }");
+
+ // important: we're calling handle() within a try block, but there's no catch block
+ // because we want to let the error propagate to the AWS Lambda runtime
+ lines.push(
+ ` return await ${client}.handle(event === null ? undefined : event);`
+ );
+ lines.push(" } finally {");
+ lines.push(" globalThis.$awsLambdaContext = undefined;");
+ lines.push(" }");
+ lines.push("};");
+
+ return lines;
+}

libs/wingsdk/src/shared-aws/function.inflight.ts

@@ -5,10 +5,21 @@ import {
  LogType,
 } from "@aws-sdk/client-lambda";
 import { fromUtf8, toUtf8 } from "@smithy/util-utf8";
+import { ILambdaContext } from "./function";
 import { IFunctionClient } from "../cloud";
 import { LogLevel, Trace, TraceType } from "../std";
 
 export class FunctionClient implements IFunctionClient {
+ public static async context(): Promise<ILambdaContext | undefined> {
+ const obj = (globalThis as any).$awsLambdaContext;
+ if (!obj) {
+ return undefined;
+ }
+ // workaround for the fact that JSII doesn't allow methods to start with "get"
+ obj.remainingTimeInMillis = obj.getRemainingTimeInMillis;
+ return obj;
+ }
+
  constructor(
  private readonly functionArn: string,
  private readonly constructPath: string,