Make the rename deployable onto an existing Worker

apps/desk/scripts/production-config.mjs

@@ -19,6 +19,20 @@ export function createProductionConfig(source, env) {
   const queueName = required(env, 'ABLE_MEDIA_QUEUE_NAME', /^[a-z0-9][a-z0-9_-]{1,62}$/)
   const config = structuredClone(source)
 
+  // A deployment may run on a Worker whose name predates this one, and the
+  // Worker name is not customer-visible when custom domains front it. Renaming
+  // a Worker in place is not possible, so allow the name to be supplied like
+  // every other deployment identifier rather than moving domains, Access
+  // policy and email routing to a differently named Worker. Optional: the
+  // committed name is the default.
+  const workerName = env.ABLE_WORKER_NAME?.trim()
+  if (workerName) {
+    // A Worker name becomes a DNS label, so it may not start or end with a
+    // hyphen, and is limited to 63 characters.
+    if (!/^[a-z0-9](?:[a-z0-9-]{0,61}[a-z0-9])?$/.test(workerName)) throw new Error('ABLE_WORKER_NAME is invalid')
+    config.name = workerName
+  }
+
   const database = config.d1_databases?.find((binding) => binding.binding === 'DB')
   const bucket = config.r2_buckets?.find((binding) => binding.binding === 'ATTACHMENTS')
   const producer = config.queues?.producers?.find((binding) => binding.binding === 'MEDIA_QUEUE')

apps/desk/test/production-config.node.test.ts

@@ -3,6 +3,7 @@ import { describe, expect, it } from 'vitest'
 import { createProductionConfig } from '../scripts/production-config.mjs'
 
 const source = {
+  name: 'able',
   d1_databases: [{ binding: 'DB', database_name: 'able', migrations_dir: 'migrations' }],
   r2_buckets: [{ binding: 'ATTACHMENTS' }],
   queues: {
@@ -38,4 +39,20 @@ describe('production Wrangler configuration', () => {
     expect(() => createProductionConfig(source, { ...variables, ABLE_R2_BUCKET_NAME: '../bucket' }))
       .toThrow('ABLE_R2_BUCKET_NAME is missing or invalid')
   })
+
+  it('keeps the committed Worker name unless a deployment supplies its own', () => {
+    // A Worker cannot be renamed in place, so a deployment already serving
+    // custom domains from an older Worker name must be able to keep it.
+    expect(createProductionConfig(source, variables).name).toBe('able')
+    expect(createProductionConfig(source, { ...variables, ABLE_WORKER_NAME: 'abledesk' }).name).toBe('abledesk')
+    expect(createProductionConfig(source, { ...variables, ABLE_WORKER_NAME: '   ' }).name).toBe('able')
+    expect(source.name).toBe('able')
+  })
+
+  it('rejects a Worker name Cloudflare would not accept', () => {
+    for (const name of ['Not Valid', 'trailing-', '-leading', 'has_underscore', 'a'.repeat(64)]) {
+      expect(() => createProductionConfig(source, { ...variables, ABLE_WORKER_NAME: name }))
+        .toThrow('ABLE_WORKER_NAME is invalid')
+    }
+  })
 })

apps/desk/wrangler.jsonc

@@ -22,10 +22,20 @@
       }
     ]
   },
+  // Migration tags are an immutable contract: Cloudflare records which tags a
+  // Worker has applied, so an already-applied tag must keep its original
+  // contents. v1 therefore still names the class as it was first created, and
+  // the rename to Able is expressed as a new tag. A fresh install applies both
+  // in sequence and lands on AbleDeskAgent; a Worker that already applied v1
+  // applies only v2 and keeps its Durable Object state.
   "migrations": [
     {
       "tag": "v1_voice_demo",
-      "new_sqlite_classes": ["AbleDeskAgent"]
+      "new_sqlite_classes": ["AbleDeskVoiceDemoAgent"]
+    },
+    {
+      "tag": "v2_rename_desk_agent",
+      "renamed_classes": [{ "from": "AbleDeskVoiceDemoAgent", "to": "AbleDeskAgent" }]
     }
   ],
   "d1_databases": [

docs/deployment.md

@@ -41,7 +41,8 @@ Keep deployment-specific resource coordinates in private Workers Builds variable
 - `ABLE_D1_DATABASE_ID`: the production D1 database UUID;
 - `ABLE_D1_DATABASE_NAME`: the production D1 database name;
 - `ABLE_R2_BUCKET_NAME`: the production attachment bucket;
-- `ABLE_MEDIA_QUEUE_NAME`: the production attachment-analysis queue.
+- `ABLE_MEDIA_QUEUE_NAME`: the production attachment-analysis queue;
+- `ABLE_WORKER_NAME`: optional; the Worker to deploy onto when it is not the committed default. A Worker cannot be renamed in place, so a deployment whose Worker predates a rename can keep serving from it instead of moving its custom domains, Access application and email routing to a differently named Worker. The Worker name is not customer-visible when custom domains front it.
 
 `npm run deploy:production` validates these values and creates an ignored, ephemeral Wrangler file for the build. It never writes the production coordinates into the public repository.