feat(ur): allow mapping specific process to specific CU

servers/ur/src/app.js

@@ -17,7 +17,6 @@ const middlewareWith = middlewareWithByStrategy[config.strategy]
 
 pipe(
   (app) => app.use(cors()),
-  (app) => app.use(express.static(config.DUMP_PATH)),
   (app) => app.get('/healthcheck', (req, res) => res.status(200).send('OK')),
   middlewareWith({ ...config }),
   (app) => {

servers/ur/src/config.js

@@ -1,4 +1,3 @@
-import { tmpdir } from 'node:os'
 import { z } from 'zod'
 
 /**
@@ -15,6 +14,11 @@ const MODE = process.env.NODE_CONFIG_ENV
 
 if (!MODE) throw new Error('NODE_CONFIG_ENV must be defined')
 
+const stringifiedJsonSchema = z.preprocess(
+  (val) => JSON.parse(val),
+  z.record(z.string())
+)
+
 /**
  * The server config is an extension of the config required by the domain (business logic).
  * This prevents our domain from being aware of the environment it is running in ie.
@@ -27,11 +31,11 @@ const serverConfigSchema = z.object({
     if (typeof val === 'number') return val
     return typeof val === 'string' ? parseInt(val) : -1
   }, z.number().positive()),
+  processToHost: stringifiedJsonSchema.nullish(),
   hosts: z.preprocess(
     (arg) => (typeof arg === 'string' ? arg.split(',').map(str => str.trim()) : arg),
     z.array(z.string().url())
   ),
-  DUMP_PATH: z.string().min(1),
   aoUnit: z.enum(['cu', 'mu']),
   strategy: z.enum(['proxy', 'redirect']),
   subrouterUrl: z.string().nullable().optional(),
@@ -53,14 +57,16 @@ const CONFIG_ENVS = {
     MODE,
     port: process.env.PORT || 3005,
     hosts: process.env.HOSTS || ['http://127.0.0.1:3005'],
-    DUMP_PATH: process.env.DUMP_PATH || tmpdir(),
+    processToHost: process.env.PROCESS_TO_HOST || JSON.stringify({}),
+
     /**
      * default to the CU for no hassle startup in development mode,
      *
      * but should consider setting explicitly in your .env
      */
     aoUnit: process.env.AO_UNIT || 'cu',
     strategy: process.env.STRATEGY || 'proxy',
+
     subrouterUrl: process.env.SUBROUTER_URL,
     surUrl: process.env.SUR_URL,
     owners: process.env.OWNERS
@@ -69,9 +75,11 @@ const CONFIG_ENVS = {
     MODE,
     port: process.env.PORT || 3005,
     hosts: process.env.HOSTS,
-    DUMP_PATH: process.env.DUMP_PATH || tmpdir(),
+    processToHost: process.env.PROCESS_TO_HOST || JSON.stringify({}),
+
     aoUnit: process.env.AO_UNIT,
     strategy: process.env.STRATEGY || 'proxy',
+
     subrouterUrl: process.env.SUBROUTER_URL,
     surUrl: process.env.SUR_URL,
     owners: process.env.OWNERS

servers/ur/src/domain.js

@@ -1,6 +1,6 @@
 import { LRUCache } from 'lru-cache'
 
-export function bailoutWith ({ fetch, subrouterUrl, surUrl, owners }) {
+export function bailoutWith ({ fetch, subrouterUrl, surUrl, owners, processToHost }) {
   const cache = new LRUCache({
     /**
        * 10MB
@@ -13,6 +13,12 @@ export function bailoutWith ({ fetch, subrouterUrl, surUrl, owners }) {
   })
 
   return async (processId) => {
+    /**
+     * If a process has a specific mapping configured,
+     * then immediately return it's mapping
+     */
+    if (processToHost && processToHost[processId]) return processToHost[processId]
+
     /**
      * All three of these must be set for the
      * subrouter logic to work so if any are

servers/ur/src/domain.test.js

@@ -79,5 +79,12 @@ describe('domain', () => {
       assert(await determineHost({ processId: 'process-123', failoverAttempt: 0 }))
       assert.equal(await determineHost({ processId: 'process-123', failoverAttempt: 0 }), 'http://foo.bar')
     })
+
+    test('should redirect to the specific host for the process', async () => {
+      const bailout = bailoutWith({ processToHost: { 'process-123': 'https://specific.host' } })
+
+      const determineHost = determineHostWith({ hosts: HOSTS, cache, bailout })
+      assert.equal(await determineHost({ processId: 'process-123', failoverAttempt: 0 }), 'https://specific.host')
+    })
   })
 })

servers/ur/src/proxy.js

@@ -14,13 +14,13 @@ import { logger } from './logger.js'
 
 import { mountRoutesWithByAoUnit } from './routes/byAoUnit.js'
 
-export function proxyWith ({ aoUnit, hosts, subrouterUrl, surUrl, owners }) {
+export function proxyWith ({ aoUnit, hosts, subrouterUrl, surUrl, owners, processToHost }) {
   const _logger = logger.child('proxy')
   _logger('Configuring to reverse proxy ao %s units...', aoUnit)
 
   const proxy = httpProxy.createProxyServer({})
 
-  const bailout = aoUnit === 'cu' ? bailoutWith({ fetch, subrouterUrl, surUrl, owners }) : undefined
+  const bailout = aoUnit === 'cu' ? bailoutWith({ fetch, subrouterUrl, surUrl, owners, processToHost }) : undefined
   const determineHost = determineHostWith({ hosts, bailout })
 
   async function trampoline (init) {

servers/ur/src/redirect.js

@@ -6,11 +6,11 @@ import { logger } from './logger.js'
 
 import { mountRoutesWithByAoUnit } from './routes/byAoUnit.js'
 
-export function redirectWith ({ aoUnit, hosts, subrouterUrl, surUrl, owners }) {
+export function redirectWith ({ aoUnit, hosts, subrouterUrl, surUrl, owners, processToHost }) {
   const _logger = logger.child('redirect')
   _logger('Configuring to redirect ao %s units...', aoUnit)
 
-  const bailout = aoUnit === 'cu' ? bailoutWith({ fetch, subrouterUrl, surUrl, owners }) : undefined
+  const bailout = aoUnit === 'cu' ? bailoutWith({ fetch, subrouterUrl, surUrl, owners, processToHost }) : undefined
   const determineHost = determineHostWith({ hosts, bailout })
 
   /**