feat: generate schema from RestApi construct

README.md

@@ -63,7 +63,9 @@ const policyStore = new PolicyStore(scope, "PolicyStore", {
 
 If you want to have type safety when defining a schema, you can accomplish this **<ins>only</ins>** in typescript. Simply use the `Schema` type exported by the `@cedar-policy/cedar-wasm`.
 
-You can also generate a simple schema from a swagger file using the static function `schemaFromOpenApiSpec` in the PolicyStore construct. This functionality replicates what you can find in the AWS Verified Permissions console.
+You can also generate simple schemas using the static functions `schemaFromOpenApiSpec` or `schemaFromRestApi` in the PolicyStore construct. This functionality replicates what you can find in the AWS Verified Permissions console.
+
+Generate a schema from an OpenAPI spec:
 
 ```ts
 const validationSettingsStrict = {
@@ -83,6 +85,26 @@ const policyStore = new PolicyStore(scope, "PolicyStore", {
 });
 ```
 
+Generate a schema from a RestApi construct:
+
+```ts
+const validationSettingsStrict = {
+  mode: ValidationSettingsMode.STRICT,
+};
+const cedarJsonSchema = PolicyStore.schemaFromRestApi(
+  new RestApi(scope, "RestApi"),
+  "UserGroup",
+);
+const cedarSchema = {
+  cedarJson: JSON.stringify(cedarJsonSchema),
+};
+const policyStore = new PolicyStore(scope, "PolicyStore", {
+  schema: cedarSchema,
+  validationSettings: validationSettingsStrict,
+  description: "Policy store with schema generated from RestApi construct",
+});
+```
+
 ## Identity Source
 
 Define Identity Source with Cognito Configuration and required properties:

rosetta/default.ts-fixture

@@ -1,6 +1,7 @@
 // Fixture with packages imported, but nothing else
 import { IdentitySource, Policy, PolicyType, PolicyTemplate, AddPolicyOptions, PolicyStore, ValidationSettingsMode } from '@cdklabs/cdk-verified-permissions';
 import { UserPool } from 'aws-cdk-lib/aws-cognito';
+import { RestApi } from 'aws-cdk-lib/aws-apigateway';
 import { Stack } from 'aws-cdk-lib';
 import { Construct } from 'constructs';
 

src/policy-store.ts

@@ -1,5 +1,6 @@
 import * as fs from 'fs';
 import * as path from 'path';
+import { RestApi } from 'aws-cdk-lib/aws-apigateway';
 import * as iam from 'aws-cdk-lib/aws-iam';
 import { CfnPolicyStore } from 'aws-cdk-lib/aws-verifiedpermissions';
 import { ArnFormat, IResource, Resource, Stack } from 'aws-cdk-lib/core';
@@ -12,6 +13,8 @@ import {
   WRITE_ACTIONS,
 } from './private/permissions';
 
+const RELEVANT_HTTP_METHODS = ['get', 'post', 'put', 'patch', 'delete', 'head'];
+
 export interface Schema {
   readonly cedarJson: string;
 }
@@ -263,7 +266,6 @@ export class PolicyStore extends PolicyStoreBase {
    * @param groupEntityTypeName optional parameter to specify the group entity type name. If passed, the schema's User type will have a parent of this type.
    */
   public static schemaFromOpenApiSpec(swaggerFilePath: string, groupEntityTypeName?: string) {
-    const RELEVANT_HTTP_METHODS = ['get', 'post', 'put', 'patch', 'delete', 'head'];
     const openApiSpecString = fs.readFileSync(swaggerFilePath, 'utf-8');
     const openApiSpec = JSON.parse(openApiSpecString) as any;
     if (!openApiSpec.paths) {
@@ -293,6 +295,31 @@ export class PolicyStore extends PolicyStoreBase {
     return buildSchema(namespace, actionNames, groupEntityTypeName);
   }
 
+  /**
+   * This method generates a schema based on an AWS CDK RestApi construct. It makes the same assumptions
+   * and decisions made in the Amazon Verified Permissions console.
+   *
+   * @param restApi The RestApi construct instance from which to generate the schema.
+   * @param groupEntityTypeName Specifies a group entity type name. If passed, the schema's User type will have a parent of this type.
+   */
+  public static schemaFromRestApi(restApi: RestApi, groupEntityTypeName?: string) {
+    const namespace = cleanUpApiNameForNamespace(restApi.restApiName);
+    const actionNames: string[] = [];
+    for (const method of restApi.methods) {
+      const pathVerb = method.httpMethod.toLowerCase();
+      const pathUrl = method.resource.path;
+      if (pathVerb === 'any') {
+        for (const verb of RELEVANT_HTTP_METHODS) {
+          actionNames.push(`${verb} ${pathUrl}`);
+        }
+      }
+	  if (RELEVANT_HTTP_METHODS.includes(pathVerb)) {
+      	actionNames.push(`${pathVerb} ${pathUrl}`);
+	  }
+    }
+    return buildSchema(namespace, actionNames, groupEntityTypeName);
+  }
+
   private readonly policyStore: CfnPolicyStore;
   /**
    * ARN of the Policy Store.

test/policy-store.test.ts

@@ -3,6 +3,7 @@ import * as path from 'path';
 import * as cedar from '@cedar-policy/cedar-wasm/nodejs';
 import { ArnFormat, Aws, Stack } from 'aws-cdk-lib';
 import { Template } from 'aws-cdk-lib/assertions';
+import { RestApi } from 'aws-cdk-lib/aws-apigateway';
 import * as iam from 'aws-cdk-lib/aws-iam';
 import { CfnPolicy, CfnPolicyStore } from 'aws-cdk-lib/aws-verifiedpermissions';
 import { getResourceLogicalId } from './utils';
@@ -624,69 +625,164 @@ describe('Policy store with policies from a path', () => {
   });
 });
 
-describe('generating schemas from OpenApi specs', () => {
-  test('generate schema from openApi spec fails if swagger file has no paths', () => {
-    expect(() => {
-      PolicyStore.schemaFromOpenApiSpec(
-        path.join(__dirname, 'schema.json'),
+describe('Policy Store schema generation', () => {
+  const expectedActions = [
+    'get /artists',
+    'post /artists',
+    'delete /artists',
+    'patch /artists/{artistId}',
+    'delete /artists/{artistId}',
+    'get /podcasts',
+    'post /podcasts',
+    'delete /podcasts',
+    'get /podcasts/{podcastId}',
+    'post /podcasts/{podcastId}',
+    'put /podcasts/{podcastId}',
+    'patch /podcasts/{podcastId}',
+    'delete /podcasts/{podcastId}',
+    'head /podcasts/{podcastId}',
+  ];
+
+  describe('generating schemas from OpenApi specs', () => {
+    test('generate schema from openApi spec fails if swagger file has no paths', () => {
+      expect(() => {
+        PolicyStore.schemaFromOpenApiSpec(
+          path.join(__dirname, 'schema.json'),
+          'UserGroup',
+        );
+      }).toThrow('Invalid OpenAPI spec - missing paths object');
+    });
+
+    test('generate schema from openApi spec with userGroups', () => {
+      // GIVEN
+      const stack = new Stack(undefined, 'Stack');
+
+      // WHEN
+      const schema = PolicyStore.schemaFromOpenApiSpec(
+        path.join(__dirname, 'podcastappswagger.json'),
         'UserGroup',
       );
-    }).toThrow();
-  });
-
-  test('generate schema from openApi spec with userGroups', () => {
-    // GIVEN
-    const stack = new Stack(undefined, 'Stack');
+      const pStore = new PolicyStore(stack, 'PolicyStore', {
+        validationSettings: {
+          mode: ValidationSettingsMode.STRICT,
+        },
+        schema: {
+          cedarJson: JSON.stringify(schema),
+        },
+      });
 
-    // WHEN
-    const schema = PolicyStore.schemaFromOpenApiSpec(
-      path.join(__dirname, 'podcastappswagger.json'),
-      'UserGroup',
-    );
-    const pStore = new PolicyStore(stack, 'PolicyStore', {
-      validationSettings: {
-        mode: ValidationSettingsMode.STRICT,
-      },
-      schema: {
-        cedarJson: JSON.stringify(schema),
-      },
+      // THEN
+      expect(pStore.schema?.cedarJson).toBeDefined();
+      expect(Object.keys(schema.PodcastApp.entityTypes)).toStrictEqual([
+        'UserGroup',
+        'User',
+        'Application',
+      ]);
+      // it should have the eight explicitly defined actions plus the 6 derived from the 'any' definition
+      expect(Object.keys(schema.PodcastApp.actions).length).toEqual(8 + 6);
+      expect(Object.keys(schema.PodcastApp.actions).sort()).toEqual(expectedActions.sort());
     });
 
-    // THEN
-    expect(pStore.schema?.cedarJson).toBeDefined();
-    expect(Object.keys(schema.PodcastApp.entityTypes)).toStrictEqual([
-      'UserGroup',
-      'User',
-      'Application',
-    ]);
-    // it should have the eight explicitly defined actions plus the 6 derived from the 'any' definition
-    expect(Object.keys(schema.PodcastApp.actions).length).toEqual(8 + 6);
+    test('generate schema from openApi spec without userGroups', () => {
+      // GIVEN
+      const stack = new Stack(undefined, 'Stack');
+
+      // WHEN
+      const schema = PolicyStore.schemaFromOpenApiSpec(
+        path.join(__dirname, 'podcastappswagger.json'),
+
+      );
+      const pStore = new PolicyStore(stack, 'PolicyStore', {
+        validationSettings: {
+          mode: ValidationSettingsMode.STRICT,
+        },
+        schema: {
+          cedarJson: JSON.stringify(schema),
+        },
+      });
+
+      // THEN
+      expect(pStore.schema?.cedarJson).toBeDefined();
+      expect(Object.keys(schema.PodcastApp.entityTypes)).toStrictEqual([
+        'User',
+        'Application',
+      ]);
+      // it should have the eight explicitly defined actions plus the 6 derived from the 'any' definition
+      expect(Object.keys(schema.PodcastApp.actions).length).toEqual(8 + 6);
+      expect(Object.keys(schema.PodcastApp.actions).sort()).toEqual(expectedActions.sort());
+    });
   });
-  test('generate schema from openApi spec without userGroups', () => {
-    // GIVEN
-    const stack = new Stack(undefined, 'Stack');
 
-    // WHEN
-    const schema = PolicyStore.schemaFromOpenApiSpec(
-      path.join(__dirname, 'podcastappswagger.json'),
+  describe('generating schemas from RestApi constructs', () => {
+    function buildRestApi() {
+      const stack = new Stack(undefined, 'Stack');
+      const api = new RestApi(stack, 'PodcastApp');
+
+      const artists = api.root.addResource('artists');
+      artists.addMethod('GET');
+      artists.addMethod('POST');
+      artists.addMethod('DELETE');
+      const artist = artists.addResource('{artistId}');
+      artist.addMethod('PATCH');
+      artist.addMethod('DELETE');
+      const podcasts = api.root.addResource('podcasts');
+      podcasts.addMethod('GET');
+      podcasts.addMethod('POST');
+      podcasts.addMethod('DELETE');
+      const podcast = podcasts.addResource('{podcastId}');
+      podcast.addMethod('ANY');
+
+	  return { stack, api };
+    }
+
+    test('generate schema from RestApi with userGroups', () => {
+      // GIVEN
+      const { stack, api } = buildRestApi();
+
+      // WHEN
+      const schema = PolicyStore.schemaFromRestApi(api, 'UserGroup');
+      const pStore = new PolicyStore(stack, 'PolicyStore', {
+        validationSettings: {
+          mode: ValidationSettingsMode.STRICT,
+        },
+        schema: {
+          cedarJson: JSON.stringify(schema),
+        },
+      });
 
-    );
-    const pStore = new PolicyStore(stack, 'PolicyStore', {
-      validationSettings: {
-        mode: ValidationSettingsMode.STRICT,
-      },
-      schema: {
-        cedarJson: JSON.stringify(schema),
-      },
+      // THEN
+      expect(pStore.schema?.cedarJson).toBeDefined();
+      expect(Object.keys(schema.PodcastApp.entityTypes)).toStrictEqual([
+        'UserGroup',
+        'User',
+        'Application',
+      ]);
+      // it should have the eight explicitly defined actions plus the 6 derived from the 'any' definition
+      expect(Object.keys(schema.PodcastApp.actions).length).toEqual(8 + 6);
+      expect(Object.keys(schema.PodcastApp.actions).sort()).toEqual(expectedActions.sort());
     });
 
-    // THEN
-    expect(pStore.schema?.cedarJson).toBeDefined();
-    expect(Object.keys(schema.PodcastApp.entityTypes)).toStrictEqual([
-      'User',
-      'Application',
-    ]);
-    // it should have the eight explicitly defined actions plus the 6 derived from the 'any' definition
-    expect(Object.keys(schema.PodcastApp.actions).length).toEqual(8 + 6);
+    test('generate schema from RestApi without userGroups', () => {
+      // GIVEN
+      const { stack, api } = buildRestApi();
+
+      // WHEN
+      const schema = PolicyStore.schemaFromRestApi(api);
+      const pStore = new PolicyStore(stack, 'PolicyStore', {
+        validationSettings: {
+          mode: ValidationSettingsMode.STRICT,
+        },
+        schema: {
+          cedarJson: JSON.stringify(schema),
+        },
+      });
+
+      // THEN
+      expect(pStore.schema?.cedarJson).toBeDefined();
+      expect(Object.keys(schema.PodcastApp.entityTypes)).toStrictEqual(['User', 'Application']);
+      // it should have the eight explicitly defined actions plus the 6 derived from the 'any' definition
+      expect(Object.keys(schema.PodcastApp.actions).length).toEqual(8 + 6);
+      expect(Object.keys(schema.PodcastApp.actions).sort()).toEqual(expectedActions.sort());
+    });
   });
 });