Add background code migration service (#26652)

packages/opencode/src/data-migration.ts

@@ -0,0 +1,59 @@
+import { Context, Effect, Layer } from "effect"
+import { Database } from "./storage/db"
+import { DataMigrationTable } from "./data-migration.sql"
+import * as Log from "@opencode-ai/core/util/log"
+import { eq } from "drizzle-orm"
+
+export type Migration<R = never> = {
+  name: string
+  run: Effect.Effect<void, unknown, R>
+}
+
+const log = Log.create({ service: "data-migration" })
+
+export interface Interface {}
+
+export class Service extends Context.Service<Service, Interface>()("@opencode/DataMigration") {}
+
+export const layer = Layer.effect(
+  Service,
+  Effect.gen(function* () {
+    const migrations: Migration[] = []
+
+    yield* Effect.gen(function* () {
+      if (migrations.length === 0) return
+
+      // Migrations run in a background fiber, so they must be resumable until
+      // their completion row is written.
+      for (const migration of migrations) {
+        const completed = Database.use((db) =>
+          db
+            .select({ name: DataMigrationTable.name })
+            .from(DataMigrationTable)
+            .where(eq(DataMigrationTable.name, migration.name))
+            .get(),
+        )
+        if (completed) continue
+
+        log.info("running data migration", { name: migration.name })
+        yield* migration.run
+        Database.use((db) =>
+          db
+            .insert(DataMigrationTable)
+            .values({ name: migration.name, time_completed: Date.now() })
+            .onConflictDoNothing()
+            .run(),
+        )
+      }
+    }).pipe(
+      Effect.tapCause((cause) => Effect.logError("failed to run data migrations", { cause })),
+      Effect.ignore,
+      Effect.forkScoped,
+    )
+    return Service.of({})
+  }),
+)
+
+export const defaultLayer = layer
+
+export * as DataMigration from "./data-migration"