feat(api): tenant-scoped sender and provider configuration

.env.example

@@ -25,6 +25,10 @@ EMAIL_PROVIDER=development
 EMAIL_ALLOW_PRODUCTION_SEND=
 EMAIL_FROM_ADDRESS=noreply@mail.example.com
 EMAIL_FROM_NAME=PostKit
+# Per-tenant sender overrides (JSON). Keys are tenantId -> environment -> sender fields.
+# TENANT_EMAIL_CONFIG_BY_ID={"inkads":{"production":{"fromAddress":"noreply@mail.inkads.example.com","fromDisplayName":"InkAds","replyTo":"support@inkads.example.com"}}}
+# Maps provider account ids to env var names whose values are Key Vault-resolved tokens.
+# TENANT_PROVIDER_ACCOUNT_SECRETS={"inkads":"FORWARD_EMAIL_TOKEN_INKADS"}
 CONTACT_INBOX_ADDRESS=
 # Optional per-host contact profiles (JSON object).
 # CONTACT_EMAIL_PROFILES_BY_HOST={"example.com":{"fromAddress":"noreply@mail.example.com","fromName":"Example","contactInboxAddress":"hello@example.com"}}

apps/api/src/config/app-configuration.ts

@@ -11,6 +11,8 @@ export const APP_CONFIGURATION_ENVIRONMENT_KEYS: Readonly<Record<string, string>
   'app:email:allowProductionSend': 'EMAIL_ALLOW_PRODUCTION_SEND',
   'app:email:fromAddress': 'EMAIL_FROM_ADDRESS',
   'app:email:fromName': 'EMAIL_FROM_NAME',
+  'app:email:tenantConfigById': 'TENANT_EMAIL_CONFIG_BY_ID',
+  'app:email:tenantProviderAccountSecrets': 'TENANT_PROVIDER_ACCOUNT_SECRETS',
   'app:email:contactInboxAddress': 'CONTACT_INBOX_ADDRESS',
   'app:email:profilesByHost': 'CONTACT_EMAIL_PROFILES_BY_HOST',
   'app:email:rateLimitPerMin': 'CONTACT_RATE_LIMIT_PER_MIN',

apps/api/src/functions/send.security.spec.ts

@@ -9,6 +9,7 @@ import {
   type TenantContext,
 } from '@singleton-sd/post-kit-types';
 import { ApiKeyTenantResolver, type TenantKeyMap } from '../tenant';
+import type { ResolvedTenantEmailConfig } from '../tenant/tenant-email-config';
 import type { TemplateStore } from '../templates';
 import { createSendHandler } from './send';
 
@@ -97,6 +98,17 @@ function tenantScopedStore(
   };
 }
 
+function stubTenantSender(
+  config: Partial<ResolvedTenantEmailConfig> = {},
+): Pick<Parameters<typeof createSendHandler>[0], 'resolveTenantEmailConfig'> {
+  return {
+    resolveTenantEmailConfig: async () => ({
+      fromAddress: 'noreply@example.com',
+      ...config,
+    }),
+  };
+}
+
 function fakeProvider(capture?: EmailSendRequest[]): EmailProvider {
   return {
     name: 'development',
@@ -134,7 +146,7 @@ describe('sendHandler — cross-tenant isolation', () => {
       tenantResolver: new ApiKeyTenantResolver(KEY_MAP),
       templateStore: store,
       emailProvider: fakeProvider(sent),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
     });
 
     const response = await handler(
@@ -160,7 +172,7 @@ describe('sendHandler — cross-tenant isolation', () => {
       tenantResolver: new ApiKeyTenantResolver(KEY_MAP),
       templateStore: store,
       emailProvider: fakeProvider(sent),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
     });
 
     const response = await handler(
@@ -183,7 +195,7 @@ describe('sendHandler — cross-tenant isolation', () => {
       tenantResolver: new ApiKeyTenantResolver(KEY_MAP),
       templateStore: store,
       emailProvider: fakeProvider(),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
     });
 
     const response = await handler(
@@ -239,7 +251,7 @@ describe('sendHandler — tenant spoofing has no effect', () => {
         tenantResolver: new ApiKeyTenantResolver(KEY_MAP),
         templateStore: store,
         emailProvider: fakeProvider(),
-        fromAddress: () => 'noreply@example.com',
+        ...stubTenantSender(),
       });
 
       const response = await handler(fakeRequest(options), fakeContext());
@@ -261,7 +273,7 @@ describe('sendHandler — tenant spoofing has no effect', () => {
       tenantResolver: new ApiKeyTenantResolver(KEY_MAP),
       templateStore: store,
       emailProvider: fakeProvider(),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
     });
 
     const response = await handler(
@@ -291,7 +303,7 @@ describe('sendHandler — environment isolation', () => {
       tenantResolver: new ApiKeyTenantResolver(KEY_MAP),
       templateStore: store,
       emailProvider: fakeProvider(sent),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
     });
 
     const response = await handler(
@@ -342,7 +354,7 @@ describe('sendHandler — unsafe template keys are rejected before storage acces
         tenantResolver: new ApiKeyTenantResolver(KEY_MAP),
         templateStore: store,
         emailProvider: fakeProvider(),
-        fromAddress: () => 'noreply@example.com',
+        ...stubTenantSender(),
       });
 
       const response = await handler(
@@ -384,7 +396,7 @@ describe('sendHandler — hostile variable values cannot inject markup', () => {
         tenantResolver: new ApiKeyTenantResolver(KEY_MAP),
         templateStore: store,
         emailProvider: fakeProvider(sent),
-        fromAddress: () => 'noreply@example.com',
+        ...stubTenantSender(),
       });
 
       const response = await handler(
@@ -424,7 +436,7 @@ describe('sendHandler — hostile variable values cannot inject markup', () => {
       tenantResolver: new ApiKeyTenantResolver(KEY_MAP),
       templateStore: store,
       emailProvider: fakeProvider(sent),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
     });
 
     await handler(
@@ -453,7 +465,7 @@ describe('sendHandler — malformed and oversized bodies produce stable typed er
       tenantResolver: new ApiKeyTenantResolver(KEY_MAP),
       templateStore: store,
       emailProvider: fakeProvider(),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
     });
     const response = await handler(fakeRequest(options), fakeContext());
     return { response, calls };

apps/api/src/functions/send.spec.ts

@@ -13,6 +13,7 @@ import {
   type TenantContext,
 } from '@singleton-sd/post-kit-types';
 import { TenantResolverError, type TenantResolver } from '../tenant';
+import type { ResolvedTenantEmailConfig } from '../tenant/tenant-email-config';
 import { TemplateStoreError, type TemplateStore } from '../templates';
 import { createLogger } from '../telemetry';
 import { createSendHandler } from './send';
@@ -71,6 +72,17 @@ function fakeStore(result: CompiledTemplate | TemplateStoreError): TemplateStore
   };
 }
 
+function stubTenantSender(
+  config: Partial<ResolvedTenantEmailConfig> = {},
+): Pick<Parameters<typeof createSendHandler>[0], 'resolveTenantEmailConfig'> {
+  return {
+    resolveTenantEmailConfig: async () => ({
+      fromAddress: 'noreply@example.com',
+      fromDisplayName: 'PostKit',
+      ...config,
+    }),
+  };
+}
 function fakeProvider(capture?: EmailSendRequest[]): EmailProvider {
   return {
     name: 'development',
@@ -89,8 +101,7 @@ describe('sendHandler', () => {
       tenantResolver: fakeResolver(),
       templateStore: fakeStore(COMPILED),
       emailProvider: fakeProvider(sent),
-      fromAddress: () => 'noreply@example.com',
-      fromName: () => 'PostKit',
+      ...stubTenantSender(),
     });
 
     const response = await handler(
@@ -117,7 +128,7 @@ describe('sendHandler', () => {
       tenantResolver: fakeResolver(),
       templateStore: fakeStore(COMPILED),
       emailProvider: fakeProvider(sent),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
     });
 
     await handler(
@@ -140,7 +151,7 @@ describe('sendHandler', () => {
       tenantResolver: fakeResolver(false),
       templateStore: fakeStore(COMPILED),
       emailProvider: fakeProvider(),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
     });
     const response = await handler(fakeRequest({ json: {} }), fakeContext());
     assert.equal(response.status, 401);
@@ -157,7 +168,7 @@ describe('sendHandler', () => {
       },
       templateStore: fakeStore(COMPILED),
       emailProvider: fakeProvider(),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
     });
     const response = await handler(fakeRequest({ json: validBody() }), fakeContext());
     assert.equal(response.status, 403);
@@ -171,7 +182,7 @@ describe('sendHandler', () => {
         new TemplateStoreError('missing', PostKitErrorCode.TEMPLATE_NOT_FOUND),
       ),
       emailProvider: fakeProvider(),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
     });
     const response = await handler(fakeRequest({ json: validBody() }), fakeContext());
     assert.equal(response.status, 404);
@@ -183,7 +194,7 @@ describe('sendHandler', () => {
       tenantResolver: fakeResolver(),
       templateStore: fakeStore(new TemplateStoreError('bad', PostKitErrorCode.INVALID_TEMPLATE)),
       emailProvider: fakeProvider(),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
     });
     const response = await handler(fakeRequest({ json: validBody() }), fakeContext());
     assert.equal(response.status, 400);
@@ -195,7 +206,7 @@ describe('sendHandler', () => {
       tenantResolver: fakeResolver(),
       templateStore: fakeStore(COMPILED),
       emailProvider: fakeProvider(),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
     });
     const response = await handler(
       fakeRequest({
@@ -212,7 +223,7 @@ describe('sendHandler', () => {
       tenantResolver: fakeResolver(),
       templateStore: fakeStore(COMPILED),
       emailProvider: fakeProvider(),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
     });
     const response = await handler(
       fakeRequest({
@@ -235,7 +246,7 @@ describe('sendHandler', () => {
         },
       },
       emailProvider: fakeProvider(),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
     });
     const response = await handler(
       fakeRequest({
@@ -265,7 +276,7 @@ describe('sendHandler', () => {
       templateStore: fakeStore(withBrandingVar),
       emailProvider: fakeProvider(sent),
       resolveBranding: async () => ({ companyName: 'InkAds' }),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
     });
 
     const response = await handler(
@@ -290,7 +301,7 @@ describe('sendHandler', () => {
       tenantResolver: fakeResolver(),
       templateStore: fakeStore(COMPILED),
       emailProvider: fakeProvider(),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
       createLogger: (correlationId) => createLogger(correlationId, (line) => lines.push(line)),
     });
 
@@ -326,7 +337,7 @@ describe('sendHandler', () => {
       tenantResolver: fakeResolver(),
       templateStore: fakeStore(COMPILED),
       emailProvider: fakeProvider(),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
       createLogger: (correlationId) => createLogger(correlationId, (line) => lines.push(line)),
     });
 
@@ -358,7 +369,7 @@ describe('sendHandler', () => {
       tenantResolver: fakeResolver(),
       templateStore: fakeStore(COMPILED),
       emailProvider: fakeProvider(),
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
       createLogger: (correlationId) => createLogger(correlationId, (line) => lines.push(line)),
     });
 
@@ -397,7 +408,7 @@ describe('sendHandler', () => {
           });
         },
       },
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
       createLogger: (correlationId) => createLogger(correlationId, (line) => lines.push(line)),
     });
 
@@ -430,7 +441,7 @@ describe('sendHandler', () => {
           });
         },
       },
-      fromAddress: () => 'noreply@example.com',
+      ...stubTenantSender(),
     });
     const response = await handler(fakeRequest({ json: validBody() }), fakeContext());
     assert.equal(response.status, 502);