Aspect to enforce unique app/region/stack on lambdas

.changeset/silent-kids-bathe.md

@@ -0,0 +1,7 @@
+---
+"@guardian/cdk": major
+---
+
+Enforce unique app/region/stack combination on `GuLambdaFunction`
+
+This is a breaking change as it will break builds for projects not using unique app/region/stack on their lambdas.

src/aspects/unique-lambda-app-region-stack.test.ts

@@ -0,0 +1,44 @@
+import { App, Stack } from "aws-cdk-lib";
+import { Runtime } from "aws-cdk-lib/aws-lambda";
+import { GuStack } from "../constructs/core";
+import { GuLambdaFunction } from "../constructs/lambda";
+import { UniqueLambdaAppRegionStackAspect } from "./unique-lambda-app-region-stack";
+
+const testLambdaProps = { handler: "index.handler", fileName: "test", runtime: Runtime.NODEJS_20_X };
+describe("UniqueAppRegionStackAspect", () => {
+  let stack: GuStack;
+  let aspect: UniqueLambdaAppRegionStackAspect;
+
+  beforeEach(() => {
+    stack = new GuStack(new App(), "TestStack", { stack: "test", stage: "CODE" });
+    aspect = new UniqueLambdaAppRegionStackAspect(stack);
+  });
+
+  it("should allow unique app combinations", () => {
+    const lambda1 = new GuLambdaFunction(stack, "Lambda1", { ...testLambdaProps, app: "app1" });
+    const lambda2 = new GuLambdaFunction(stack, "Lambda2", { ...testLambdaProps, app: "app2" });
+
+    expect(() => {
+      aspect.visit(lambda1);
+      aspect.visit(lambda2);
+    }).not.toThrow();
+  });
+
+  it("should throw error for duplicate app combinations", () => {
+    const lambda1 = new GuLambdaFunction(stack, "Lambda1", { ...testLambdaProps, app: "app1" });
+    const lambda2 = new GuLambdaFunction(stack, "Lambda2", { ...testLambdaProps, app: "app1" });
+
+    expect(() => {
+      aspect.visit(lambda1);
+      aspect.visit(lambda2);
+    }).toThrow("GuLambdaFunction must have a unique combination of app, region and stack");
+  });
+
+  it("should ignore non-GuLambdaFunction constructs", () => {
+    const nonLambdaConstruct = new Stack();
+
+    expect(() => {
+      aspect.visit(nonLambdaConstruct);
+    }).not.toThrow();
+  });
+});

src/aspects/unique-lambda-app-region-stack.ts

@@ -0,0 +1,27 @@
+import type { IAspect, Stack } from "aws-cdk-lib";
+import type { IConstruct } from "constructs";
+import { GuLambdaFunction } from "../constructs/lambda";
+
+export class UniqueLambdaAppRegionStackAspect implements IAspect {
+  readonly stack: Stack;
+  private seenCombinations = new Set<string>();
+
+  // eslint-disable-next-line custom-rules/valid-constructors -- doesn't apply here
+  public constructor(stack: Stack) {
+    this.stack = stack;
+  }
+
+  public visit(node: IConstruct): void {
+    if (node instanceof GuLambdaFunction) {
+      const combination = `${this.stack.region}:${this.stack.stackName}:${node.app}`;
+
+      if (this.seenCombinations.has(combination)) {
+        throw new Error(
+          `GuLambdaFunction must have a unique combination of app, region and stack. Found duplicate: ${node.app}`,
+        );
+      }
+
+      this.seenCombinations.add(combination);
+    }
+  }
+}

src/constructs/core/stack.ts

@@ -5,6 +5,7 @@ import gitUrlParse from "git-url-parse";
 import { CfnIncludeReporter } from "../../aspects/cfn-include-reporter";
 import { CfnParameterReporter } from "../../aspects/cfn-parameter-reporter";
 import { Metadata } from "../../aspects/metadata";
+import { UniqueLambdaAppRegionStackAspect } from "../../aspects/unique-lambda-app-region-stack";
 import { ContextKeys, MetadataKeys, TrackingTag } from "../../constants";
 import { gitRemoteOriginUrl } from "../../utils/git";
 import type { StackStageIdentity } from "./identity";
@@ -151,6 +152,7 @@ export class GuStack extends Stack implements StackStageIdentity {
 
     Aspects.of(this).add(new CfnIncludeReporter());
     Aspects.of(this).add(new CfnParameterReporter());
+    Aspects.of(this).add(new UniqueLambdaAppRegionStackAspect(this));
   }
 
   /**

src/constructs/lambda/lambda.ts

@@ -7,10 +7,11 @@ import { Bucket } from "aws-cdk-lib/aws-s3";
 import { StringParameter } from "aws-cdk-lib/aws-ssm";
 import { GuDistributable } from "../../types";
 import type { GuLambdaErrorPercentageMonitoringProps, GuLambdaThrottlingMonitoringProps } from "../cloudwatch";
-import { GuLambdaErrorPercentageAlarm, GuLambdaThrottlingAlarm } from "../cloudwatch";
+import { GuLambdaErrorPercentageAlarm, GuLambdaThrottlingAlarm } from "../cloudwatch/lambda-alarms";
 import type { GuStack } from "../core";
-import { AppIdentity, GuDistributionBucketParameter } from "../core";
-import { ReadParametersByName, ReadParametersByPath } from "../iam";
+import { AppIdentity } from "../core/identity";
+import { GuDistributionBucketParameter } from "../core/parameters/s3";
+import { ReadParametersByName, ReadParametersByPath } from "../iam/policies/parameter-store-read";
 
 export interface GuFunctionProps extends GuDistributable, Omit<FunctionProps, "code">, AppIdentity {
   /**

src/patterns/__snapshots__/api-multiple-lambdas.test.ts.snap

@@ -740,11 +740,11 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
           "S3Bucket": {
             "Ref": "DistributionBucketName",
           },
-          "S3Key": "test-stack/TEST/testing/my-app-4.zip",
+          "S3Key": "test-stack/TEST/my-app-4/my-app-4.zip",
         },
         "Environment": {
           "Variables": {
-            "APP": "testing",
+            "APP": "my-app-4",
             "STACK": "test-stack",
             "STAGE": "TEST",
           },
@@ -764,7 +764,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
         "Tags": [
           {
             "Key": "App",
-            "Value": "testing",
+            "Value": "my-app-4",
           },
           {
             "Key": "gu:cdk:version",
@@ -818,7 +818,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
         "Tags": [
           {
             "Key": "App",
-            "Value": "testing",
+            "Value": "my-app-4",
           },
           {
             "Key": "gu:cdk:version",
@@ -879,7 +879,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
                       {
                         "Ref": "DistributionBucketName",
                       },
-                      "/test-stack/TEST/testing/my-app-4.zip",
+                      "/test-stack/TEST/my-app-4/my-app-4.zip",
                     ],
                   ],
                 },
@@ -900,7 +900,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
                     {
                       "Ref": "AWS::AccountId",
                     },
-                    ":parameter/TEST/test-stack/testing",
+                    ":parameter/TEST/test-stack/my-app-4",
                   ],
                 ],
               },
@@ -923,7 +923,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
                     {
                       "Ref": "AWS::AccountId",
                     },
-                    ":parameter/TEST/test-stack/testing/*",
+                    ":parameter/TEST/test-stack/my-app-4/*",
                   ],
                 ],
               },
@@ -950,11 +950,11 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
           "S3Bucket": {
             "Ref": "DistributionBucketName",
           },
-          "S3Key": "test-stack/TEST/testing/my-app-1.zip",
+          "S3Key": "test-stack/TEST/my-app-1/my-app-1.zip",
         },
         "Environment": {
           "Variables": {
-            "APP": "testing",
+            "APP": "my-app-1",
             "STACK": "test-stack",
             "STAGE": "TEST",
           },
@@ -974,7 +974,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
         "Tags": [
           {
             "Key": "App",
-            "Value": "testing",
+            "Value": "my-app-1",
           },
           {
             "Key": "gu:cdk:version",
@@ -1036,7 +1036,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
                       {
                         "Ref": "DistributionBucketName",
                       },
-                      "/test-stack/TEST/testing/my-app-1.zip",
+                      "/test-stack/TEST/my-app-1/my-app-1.zip",
                     ],
                   ],
                 },
@@ -1057,7 +1057,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
                     {
                       "Ref": "AWS::AccountId",
                     },
-                    ":parameter/TEST/test-stack/testing",
+                    ":parameter/TEST/test-stack/my-app-1",
                   ],
                 ],
               },
@@ -1080,7 +1080,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
                     {
                       "Ref": "AWS::AccountId",
                     },
-                    ":parameter/TEST/test-stack/testing/*",
+                    ":parameter/TEST/test-stack/my-app-1/*",
                   ],
                 ],
               },
@@ -1128,7 +1128,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
         "Tags": [
           {
             "Key": "App",
-            "Value": "testing",
+            "Value": "my-app-1",
           },
           {
             "Key": "gu:cdk:version",
@@ -1160,11 +1160,11 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
           "S3Bucket": {
             "Ref": "DistributionBucketName",
           },
-          "S3Key": "test-stack/TEST/testing/my-app-3.zip",
+          "S3Key": "test-stack/TEST/my-app-3/my-app-3.zip",
         },
         "Environment": {
           "Variables": {
-            "APP": "testing",
+            "APP": "my-app-3",
             "STACK": "test-stack",
             "STAGE": "TEST",
           },
@@ -1184,7 +1184,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
         "Tags": [
           {
             "Key": "App",
-            "Value": "testing",
+            "Value": "my-app-3",
           },
           {
             "Key": "gu:cdk:version",
@@ -1238,7 +1238,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
         "Tags": [
           {
             "Key": "App",
-            "Value": "testing",
+            "Value": "my-app-3",
           },
           {
             "Key": "gu:cdk:version",
@@ -1299,7 +1299,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
                       {
                         "Ref": "DistributionBucketName",
                       },
-                      "/test-stack/TEST/testing/my-app-3.zip",
+                      "/test-stack/TEST/my-app-3/my-app-3.zip",
                     ],
                   ],
                 },
@@ -1320,7 +1320,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
                     {
                       "Ref": "AWS::AccountId",
                     },
-                    ":parameter/TEST/test-stack/testing",
+                    ":parameter/TEST/test-stack/my-app-3",
                   ],
                 ],
               },
@@ -1343,7 +1343,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
                     {
                       "Ref": "AWS::AccountId",
                     },
-                    ":parameter/TEST/test-stack/testing/*",
+                    ":parameter/TEST/test-stack/my-app-3/*",
                   ],
                 ],
               },
@@ -1370,11 +1370,11 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
           "S3Bucket": {
             "Ref": "DistributionBucketName",
           },
-          "S3Key": "test-stack/TEST/testing/my-app-2.zip",
+          "S3Key": "test-stack/TEST/my-app-2/my-app-2.zip",
         },
         "Environment": {
           "Variables": {
-            "APP": "testing",
+            "APP": "my-app-2",
             "STACK": "test-stack",
             "STAGE": "TEST",
           },
@@ -1394,7 +1394,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
         "Tags": [
           {
             "Key": "App",
-            "Value": "testing",
+            "Value": "my-app-2",
           },
           {
             "Key": "gu:cdk:version",
@@ -1448,7 +1448,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
         "Tags": [
           {
             "Key": "App",
-            "Value": "testing",
+            "Value": "my-app-2",
           },
           {
             "Key": "gu:cdk:version",
@@ -1509,7 +1509,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
                       {
                         "Ref": "DistributionBucketName",
                       },
-                      "/test-stack/TEST/testing/my-app-2.zip",
+                      "/test-stack/TEST/my-app-2/my-app-2.zip",
                     ],
                   ],
                 },
@@ -1530,7 +1530,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
                     {
                       "Ref": "AWS::AccountId",
                     },
-                    ":parameter/TEST/test-stack/testing",
+                    ":parameter/TEST/test-stack/my-app-2",
                   ],
                 ],
               },
@@ -1553,7 +1553,7 @@ exports[`The GuApiGatewayWithLambdaByPath pattern should create the correct reso
                     {
                       "Ref": "AWS::AccountId",
                     },
-                    ":parameter/TEST/test-stack/testing/*",
+                    ":parameter/TEST/test-stack/my-app-2/*",
                   ],
                 ],
               },