fix(region-info): incorrect codedeploy service principals (aws#18505)

In "special" regions (GovCloud, US-ISO), the CodeDeploy service
principal uses the `amazonaws.com` DNS suffix. In fact, that is true of
all regions, in all partitions, with the notable exception of `aws-cn`
which uses the `amazonaws.com.cn` suffix instead.


----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

packages/@aws-cdk/aws-codedeploy/test/lambda/deployment-group.test.ts

@@ -87,7 +87,15 @@ describe('CodeDeploy Lambda DeploymentGroup', () => {
           Action: 'sts:AssumeRole',
           Effect: 'Allow',
           Principal: {
-            Service: { 'Fn::Join': ['', ['codedeploy.', { Ref: 'AWS::Region' }, '.', { Ref: 'AWS::URLSuffix' }]] },
+            Service: {
+              'Fn::FindInMap': [
+                'ServiceprincipalMap',
+                {
+                  Ref: 'AWS::Region',
+                },
+                'codedeploy',
+              ],
+            },
           },
         }],
         Version: '2012-10-17',

packages/@aws-cdk/region-info/lib/aws-entities.ts

@@ -1,17 +1,14 @@
-// Rule prefix
-const RULE_ = 'RULE_';
-
 /**
  * After this point, SSM only creates regional principals
  */
-export const RULE_SSM_PRINCIPALS_ARE_REGIONAL = `${RULE_}SSM_PRINCIPALS_ARE_REGIONAL`;
+export const RULE_SSM_PRINCIPALS_ARE_REGIONAL = Symbol('SSM_PRINCIPALS_ARE_REGIONAL');
 
 /**
  * After this point, S3 website domains look like `s3-website.REGION.s3.amazonaws.com`
  *
  * Before this point, S3 website domains look like `s3-website-REGION.s3.amazonaws.com`.
  */
-export const RULE_S3_WEBSITE_REGIONAL_SUBDOMAIN = `${RULE_}S3_WEBSITE_REGIONAL_SUBDOMAIN`;
+export const RULE_S3_WEBSITE_REGIONAL_SUBDOMAIN = Symbol('S3_WEBSITE_REGIONAL_SUBDOMAIN');
 
 /**
  * List of AWS region, ordered by launch date (oldest to newest)
@@ -21,13 +18,13 @@ export const RULE_S3_WEBSITE_REGIONAL_SUBDOMAIN = `${RULE_}S3_WEBSITE_REGIONAL_S
  * regions are left as-is.
  *
  * We mix the list of regions with a list of rules that were introduced over
- * time (rules are strings starting with `RULE_`).
+ * time (rules are symbols).
  *
  * Therefore, if we want to know if a rule applies to a certain region, we
  * only need to check its position in the list and compare it to when a
  * rule was introduced.
  */
-export const AWS_REGIONS_AND_RULES = [
+export const AWS_REGIONS_AND_RULES: readonly (string | symbol)[] = [
   'us-east-1', // US East (N. Virginia)
   'eu-west-1', // Europe (Ireland)
   'us-west-1', // US West (N. California)
@@ -68,15 +65,15 @@ export const AWS_REGIONS_AND_RULES = [
  * Not in the list ==> no built-in data for that region.
  */
 export const AWS_REGIONS = AWS_REGIONS_AND_RULES
-  .filter((x) => !x.startsWith(RULE_))
-  .sort();
+  .filter((x) => typeof x === 'string')
+  .sort() as readonly string[];
 
 /**
  * Possibly non-exaustive list of all service names, used to locate service principals.
  *
  * Not in the list ==> default service principal mappings.
  */
-export const AWS_SERVICES = [
+export const AWS_SERVICES: readonly string[] = [
   'application-autoscaling',
   'autoscaling',
   'codedeploy',
@@ -96,10 +93,10 @@ export const AWS_SERVICES = [
  *
  * Unknown region => we have to assume no.
  */
-export function before(region: string, ruleOrRegion: string) {
+export function before(region: string, ruleOrRegion: string | symbol) {
   const ruleIx = AWS_REGIONS_AND_RULES.indexOf(ruleOrRegion);
   if (ruleIx === -1) {
-    throw new Error(`Unknown rule: ${ruleOrRegion}`);
+    throw new Error(`Unknown rule: ${String(ruleOrRegion)}`);
   }
   const regionIx = AWS_REGIONS_AND_RULES.indexOf(region);
   return regionIx === -1 ? false : regionIx < ruleIx;
@@ -108,17 +105,19 @@ export function before(region: string, ruleOrRegion: string) {
 /**
  * Return all regions before a given rule was introduced (or region)
  */
-export function regionsBefore(ruleOrRegion: string): string[] {
+export function regionsBefore(ruleOrRegion: string | symbol): string[] {
   const ruleIx = AWS_REGIONS_AND_RULES.indexOf(ruleOrRegion);
   if (ruleIx === -1) {
-    throw new Error(`Unknown rule: ${ruleOrRegion}`);
+    throw new Error(`Unknown rule: ${String(ruleOrRegion)}`);
   }
-  return AWS_REGIONS_AND_RULES.filter((_, i) => i < ruleIx).sort();
+  return AWS_REGIONS_AND_RULES.slice(0, ruleIx)
+    .filter((entry) => typeof entry === 'string')
+    .sort() as string[];
 }
 
-export interface Region { partition: string, domainSuffix: string }
+export interface Region { readonly partition: string, readonly domainSuffix: string }
 
-const PARTITION_MAP: { [region: string]: Region } = {
+const PARTITION_MAP: {readonly [region: string]: Region } = {
   'default': { partition: 'aws', domainSuffix: 'amazonaws.com' },
   'cn-': { partition: 'aws-cn', domainSuffix: 'amazonaws.com.cn' },
   'us-gov-': { partition: 'aws-us-gov', domainSuffix: 'amazonaws.com' },

packages/@aws-cdk/region-info/lib/default.ts

@@ -23,8 +23,8 @@ export class Default {
    * @param urlSuffix deprecated and ignored.
    */
   public static servicePrincipal(serviceFqn: string, region: string, urlSuffix: string): string {
-    const service = extractSimpleName(serviceFqn);
-    if (!service) {
+    const serviceName = extractSimpleName(serviceFqn);
+    if (!serviceName) {
       // Return "service" if it does not look like any of the following:
       // - s3
       // - s3.amazonaws.com
@@ -34,72 +34,86 @@ export class Default {
       return serviceFqn;
     }
 
-    // Exceptions for Service Principals in us-iso-*
-    const US_ISO_EXCEPTIONS = new Set([
-      'cloudhsm',
-      'config',
-      'states',
-      'workspaces',
-    ]);
-
-    // Account for idiosyncratic Service Principals in `us-iso-*` regions
-    if (region.startsWith('us-iso-') && US_ISO_EXCEPTIONS.has(service)) {
-      switch (service) {
-        // Services with universal principal
-        case ('states'):
-          return `${service}.amazonaws.com`;
-
-        // Services with a partitional principal
-        default:
-          return `${service}.${urlSuffix}`;
+    function determineConfiguration(service: string): (service: string, region: string, urlSuffix: string) => string {
+      function universal(s: string) { return `${s}.amazonaws.com`; };
+      function partitional(s: string, _: string, u: string) { return `${s}.${u}`; };
+      function regional(s: string, r: string) { return `${s}.${r}.amazonaws.com`; };
+      function regionalPartitional(s: string, r: string, u: string) { return `${s}.${r}.${u}`; };
+
+      // Exceptions for Service Principals in us-iso-*
+      const US_ISO_EXCEPTIONS = new Set([
+        'cloudhsm',
+        'config',
+        'states',
+        'workspaces',
+      ]);
+
+      // Account for idiosyncratic Service Principals in `us-iso-*` regions
+      if (region.startsWith('us-iso-') && US_ISO_EXCEPTIONS.has(service)) {
+        switch (service) {
+          // Services with universal principal
+          case ('states'):
+            return universal;
+
+          // Services with a partitional principal
+          default:
+            return partitional;
+        }
       }
-    }
 
-    // Exceptions for Service Principals in us-isob-*
-    const US_ISOB_EXCEPTIONS = new Set([
-      'dms',
-      'states',
-    ]);
+      // Exceptions for Service Principals in us-isob-*
+      const US_ISOB_EXCEPTIONS = new Set([
+        'dms',
+        'states',
+      ]);
+
+      // Account for idiosyncratic Service Principals in `us-isob-*` regions
+      if (region.startsWith('us-isob-') && US_ISOB_EXCEPTIONS.has(service)) {
+        switch (service) {
+          // Services with universal principal
+          case ('states'):
+            return universal;
+
+          // Services with a partitional principal
+          default:
+            return partitional;
+        }
+      }
 
-    // Account for idiosyncratic Service Principals in `us-isob-*` regions
-    if (region.startsWith('us-isob-') && US_ISOB_EXCEPTIONS.has(service)) {
       switch (service) {
-        // Services with universal principal
-        case ('states'):
-          return `${service}.amazonaws.com`;
+        // SSM turned from global to regional at some point
+        case 'ssm':
+          return before(region, RULE_SSM_PRINCIPALS_ARE_REGIONAL)
+            ? universal
+            : regional;
+
+        // CodeDeploy is regional+partitional in CN, only regional everywhere else
+        case 'codedeploy':
+          return region.startsWith('cn-')
+            ? regionalPartitional
+            : regional;
+
+        // Services with a regional AND partitional principal
+        case 'logs':
+          return regionalPartitional;
+
+        // Services with a regional principal
+        case 'states':
+          return regional;
 
         // Services with a partitional principal
-        default:
-          return `${service}.${urlSuffix}`;
-      }
-    }
-
-    // SSM turned from global to regional at some point
-    if (service === 'ssm') {
-      return before(region, RULE_SSM_PRINCIPALS_ARE_REGIONAL)
-        ? `${service}.amazonaws.com`
-        : `${service}.${region}.amazonaws.com`;
-    }
-
-    switch (service) {
-      // Services with a regional AND partitional principal
-      case 'codedeploy':
-      case 'logs':
-        return `${service}.${region}.${urlSuffix}`;
-
-      // Services with a regional principal
-      case 'states':
-        return `${service}.${region}.amazonaws.com`;
+        case 'ec2':
+          return partitional;
 
-      // Services with a partitional principal
-      case 'ec2':
-        return `${service}.${urlSuffix}`;
+        // Services with a universal principal across all regions/partitions (the default case)
+        default:
+          return universal;
 
-      // Services with a universal principal across all regions/partitions (the default case)
-      default:
-        return `${service}.amazonaws.com`;
+      }
+    };
 
-    }
+    const configuration = determineConfiguration(serviceName);
+    return configuration(serviceName, region, urlSuffix);
   }
 
   private constructor() { }
@@ -108,4 +122,4 @@ export class Default {
 function extractSimpleName(serviceFqn: string) {
   const matches = serviceFqn.match(/^([^.]+)(?:(?:\.amazonaws\.com(?:\.cn)?)|(?:\.c2s\.ic\.gov)|(?:\.sc2s\.sgov\.gov))?$/);
   return matches ? matches[1] : undefined;
-}
+}

packages/@aws-cdk/region-info/lib/fact.ts

@@ -9,7 +9,8 @@ export class Fact {
    *          may not be an exhaustive list of all available AWS regions.
    */
   public static get regions(): string[] {
-    return AWS_REGIONS;
+    // Return by copy to ensure no modifications can be made to the undelying constant.
+    return Array.from(AWS_REGIONS);
   }
 
   /**

packages/@aws-cdk/region-info/test/__snapshots__/region-info.test.js.snap

@@ -795,7 +795,7 @@ Object {
     "servicePrincipals": Object {
       "application-autoscaling": "application-autoscaling.amazonaws.com",
       "autoscaling": "autoscaling.amazonaws.com",
-      "codedeploy": "codedeploy.us-iso-east-1.c2s.ic.gov",
+      "codedeploy": "codedeploy.us-iso-east-1.amazonaws.com",
       "ec2": "ec2.c2s.ic.gov",
       "events": "events.amazonaws.com",
       "lambda": "lambda.amazonaws.com",
@@ -826,7 +826,7 @@ Object {
     "servicePrincipals": Object {
       "application-autoscaling": "application-autoscaling.amazonaws.com",
       "autoscaling": "autoscaling.amazonaws.com",
-      "codedeploy": "codedeploy.us-iso-west-1.c2s.ic.gov",
+      "codedeploy": "codedeploy.us-iso-west-1.amazonaws.com",
       "ec2": "ec2.c2s.ic.gov",
       "events": "events.amazonaws.com",
       "lambda": "lambda.amazonaws.com",
@@ -857,7 +857,7 @@ Object {
     "servicePrincipals": Object {
       "application-autoscaling": "application-autoscaling.amazonaws.com",
       "autoscaling": "autoscaling.amazonaws.com",
-      "codedeploy": "codedeploy.us-isob-east-1.sc2s.sgov.gov",
+      "codedeploy": "codedeploy.us-isob-east-1.amazonaws.com",
       "ec2": "ec2.sc2s.sgov.gov",
       "events": "events.amazonaws.com",
       "lambda": "lambda.amazonaws.com",

packages/@aws-cdk/region-info/test/default.test.ts

@@ -5,12 +5,12 @@ const urlSuffix = '.nowhere.null';
 
 describe('servicePrincipal', () => {
   for (const suffix of ['', '.amazonaws.com', '.amazonaws.com.cn']) {
-    for (const service of ['states', 'ssm']) {
+    for (const service of ['codedeploy', 'states', 'ssm']) {
       test(`${service}${suffix}`, () => {
         expect(Default.servicePrincipal(`${service}${suffix}`, region, urlSuffix)).toBe(`${service}.${region}.amazonaws.com`);
       });
     }
-    for (const service of ['codedeploy', 'logs']) {
+    for (const service of ['logs']) {
       test(`${service}${suffix}`, () => {
         expect(Default.servicePrincipal(`${service}${suffix}`, region, urlSuffix)).toBe(`${service}.${region}.${urlSuffix}`);
       });
@@ -48,6 +48,12 @@ describe('servicePrincipal', () => {
     });
   }
 
+  for (const cnRegion of ['cn-north-1', 'cn-northwest-1']) {
+    test(`Exceptions: codedeploy in ${cnRegion}`, () => {
+      expect(Default.servicePrincipal('codedeploy', cnRegion, 'amazonaws.com.cn')).toBe(`codedeploy.${cnRegion}.amazonaws.com.cn`);
+    });
+  }
+
 });