From 303528d7553c249c73845904bdeea11bc747672c Mon Sep 17 00:00:00 2001
From: Steven Ontong <steven@journeyapps.com>
Date: Mon, 14 Oct 2024 16:18:12 +0200
Subject: [PATCH 01/13] rename parameters

---
 .../service-core/src/util/config/compound-config-collector.ts | 3 ++-
 packages/service-core/src/util/config/types.ts                | 1 +
 packages/types/src/config/PowerSyncConfig.ts                  | 4 +++-
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/packages/service-core/src/util/config/compound-config-collector.ts b/packages/service-core/src/util/config/compound-config-collector.ts
index 78e8500cb..7c2b70c87 100644
--- a/packages/service-core/src/util/config/compound-config-collector.ts
+++ b/packages/service-core/src/util/config/compound-config-collector.ts
@@ -122,7 +122,8 @@ export class CompoundConfigCollector {
       },
       // TODO maybe move this out of the connection or something
       // slot_name_prefix: connections[0]?.slot_name_prefix ?? 'powersync_'
-      slot_name_prefix: 'powersync_'
+      slot_name_prefix: 'powersync_',
+      parameters: baseConfig.parameters ?? {}
     };
 
     return config;
diff --git a/packages/service-core/src/util/config/types.ts b/packages/service-core/src/util/config/types.ts
index e5f461e49..99829526d 100644
--- a/packages/service-core/src/util/config/types.ts
+++ b/packages/service-core/src/util/config/types.ts
@@ -64,4 +64,5 @@ export type ResolvedPowerSyncConfig = {
 
   /** Prefix for postgres replication slot names. May eventually be connection-specific. */
   slot_name_prefix: string;
+  parameters: Record<string, number | string | boolean | null>;
 };
diff --git a/packages/types/src/config/PowerSyncConfig.ts b/packages/types/src/config/PowerSyncConfig.ts
index e9dff54f4..dbd33e1ae 100644
--- a/packages/types/src/config/PowerSyncConfig.ts
+++ b/packages/types/src/config/PowerSyncConfig.ts
@@ -135,7 +135,9 @@ export const powerSyncConfig = t.object({
       disable_telemetry_sharing: t.boolean,
       internal_service_endpoint: t.string.optional()
     })
-    .optional()
+    .optional(),
+
+  parameters: t.record(t.number.or(t.string).or(t.boolean).or(t.Null)).optional()
 });
 
 export type PowerSyncConfig = t.Decoded<typeof powerSyncConfig>;

From 86072e37393a9adaf66da52195cda3dab6f25a65 Mon Sep 17 00:00:00 2001
From: Steven Ontong <steven@journeyapps.com>
Date: Wed, 16 Oct 2024 13:29:08 +0200
Subject: [PATCH 02/13] Allow listening to active sync rules. Allow changing
 WriteCheckpoint mode after the fact

---
 .../service-core/src/storage/BucketStorage.ts |  7 ++++
 .../src/storage/MongoBucketStorage.ts         | 34 +++++++++++++++----
 .../storage/mongo/MongoWriteCheckpointAPI.ts  | 23 ++++++++-----
 .../src/storage/write-checkpoint.ts           |  2 ++
 4 files changed, 52 insertions(+), 14 deletions(-)

diff --git a/packages/service-core/src/storage/BucketStorage.ts b/packages/service-core/src/storage/BucketStorage.ts
index 9c12e805c..14d95fdd6 100644
--- a/packages/service-core/src/storage/BucketStorage.ts
+++ b/packages/service-core/src/storage/BucketStorage.ts
@@ -90,6 +90,11 @@ export interface BucketStorageFactory
    */
   getActiveCheckpoint(): Promise<ActiveCheckpoint>;
 
+  /**
+   * Yields the latest sync checkpoint.
+   */
+  watchActiveCheckpoint(signal: AbortSignal): AsyncIterable<ActiveCheckpoint>;
+
   /**
    * Yields the latest user write checkpoint whenever the sync checkpoint updates.
    */
@@ -118,6 +123,8 @@ export interface ActiveCheckpoint {
   hasSyncRules(): boolean;
 
   getBucketStorage(): Promise<SyncRulesBucketStorage | null>;
+
+  syncRules: PersistedSyncRules | null;
 }
 
 export interface StorageMetrics {
diff --git a/packages/service-core/src/storage/MongoBucketStorage.ts b/packages/service-core/src/storage/MongoBucketStorage.ts
index c0254da71..e86425d54 100644
--- a/packages/service-core/src/storage/MongoBucketStorage.ts
+++ b/packages/service-core/src/storage/MongoBucketStorage.ts
@@ -78,6 +78,9 @@ export class MongoBucketStorage
     db: PowerSyncMongo,
     options: {
       slot_name_prefix: string;
+      /**
+       * Initial Write Checkpoint Mode
+       */
       write_checkpoint_mode?: WriteCheckpointMode;
     }
   ) {
@@ -303,6 +306,10 @@ export class MongoBucketStorage
     return this.writeCheckpointAPI.batchCreateCustomWriteCheckpoints(checkpoints);
   }
 
+  setWriteCheckpointMode(mode: WriteCheckpointMode): void {
+    return this.writeCheckpointAPI.setWriteCheckpointMode(mode);
+  }
+
   async createCustomWriteCheckpoint(options: CustomWriteCheckpointOptions): Promise<bigint> {
     return this.writeCheckpointAPI.createCustomWriteCheckpoint(options);
   }
@@ -408,14 +415,19 @@ export class MongoBucketStorage
           return null;
         }
         return (await this.storageCache.fetch(doc._id)) ?? null;
-      }
-    };
+      },
+      syncRules: doc
+        ? new MongoPersistedSyncRulesContent(this.db, doc).parsed({
+            defaultSchema: ''
+          })
+        : null
+    } satisfies ActiveCheckpoint;
   }
 
   /**
    * Instance-wide watch on the latest available checkpoint (op_id + lsn).
    */
-  private async *watchActiveCheckpoint(signal: AbortSignal): AsyncIterable<ActiveCheckpoint> {
+  private async *_watchActiveCheckpoint(signal: AbortSignal): AsyncIterable<ActiveCheckpoint> {
     const pipeline: mongo.Document[] = [
       {
         $match: {
@@ -428,7 +440,8 @@ export class MongoBucketStorage
           operationType: 1,
           'fullDocument._id': 1,
           'fullDocument.last_checkpoint': 1,
-          'fullDocument.last_checkpoint_lsn': 1
+          'fullDocument.last_checkpoint_lsn': 1,
+          'fullDocument.content': 1
         }
       }
     ];
@@ -450,7 +463,8 @@ export class MongoBucketStorage
           projection: {
             _id: 1,
             last_checkpoint: 1,
-            last_checkpoint_lsn: 1
+            last_checkpoint_lsn: 1,
+            content: 1
           }
         }
       );
@@ -499,6 +513,7 @@ export class MongoBucketStorage
       if (doc == null) {
         continue;
       }
+
       const op = this.makeActiveCheckpoint(doc);
       // Check for LSN / checkpoint changes - ignore other metadata changes
       if (lastOp == null || op.lsn != lastOp.lsn || op.checkpoint != lastOp.checkpoint) {
@@ -510,9 +525,16 @@ export class MongoBucketStorage
 
   // Nothing is done here until a subscriber starts to iterate
   private readonly sharedIter = new sync.BroadcastIterable((signal) => {
-    return this.watchActiveCheckpoint(signal);
+    return this._watchActiveCheckpoint(signal);
   });
 
+  /**
+   * Watch changes to the active sync rules and checkpoint.
+   */
+  watchActiveCheckpoint(signal: AbortSignal): AsyncIterable<ActiveCheckpoint> {
+    return wrapWithAbort(this.sharedIter, signal);
+  }
+
   /**
    * User-specific watch on the latest checkpoint and/or write checkpoint.
    */
diff --git a/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts b/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts
index 230db3153..d466173f5 100644
--- a/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts
+++ b/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts
@@ -17,11 +17,19 @@ export type MongoCheckpointAPIOptions = {
 
 export class MongoWriteCheckpointAPI implements WriteCheckpointAPI {
   readonly db: PowerSyncMongo;
-  readonly mode: WriteCheckpointMode;
+  private _mode: WriteCheckpointMode;
 
   constructor(options: MongoCheckpointAPIOptions) {
     this.db = options.db;
-    this.mode = options.mode;
+    this._mode = options.mode;
+  }
+
+  get mode() {
+    return this._mode;
+  }
+
+  setWriteCheckpointMode(mode: WriteCheckpointMode): void {
+    this._mode = mode;
   }
 
   async batchCreateCustomWriteCheckpoints(checkpoints: CustomWriteCheckpointOptions[]): Promise<void> {
@@ -29,12 +37,11 @@ export class MongoWriteCheckpointAPI implements WriteCheckpointAPI {
   }
 
   async createCustomWriteCheckpoint(options: CustomWriteCheckpointOptions): Promise<bigint> {
-    if (this.mode !== WriteCheckpointMode.CUSTOM) {
-      throw new framework.errors.ValidationError(
-        `Creating a custom Write Checkpoint when the current Write Checkpoint mode is set to "${this.mode}"`
-      );
-    }
-
+    /**
+     * Allow creating custom checkpoints even if the current mode is not `custom`.
+     * There might be a state where the next sync rules rely on replicating custom
+     * write checkpoints, but the current active sync rules uses managed checkpoints.
+     */
     const { checkpoint, user_id, sync_rules_id } = options;
     const doc = await this.db.custom_write_checkpoints.findOneAndUpdate(
       {
diff --git a/packages/service-core/src/storage/write-checkpoint.ts b/packages/service-core/src/storage/write-checkpoint.ts
index 0b61fe0c1..0a45dbffd 100644
--- a/packages/service-core/src/storage/write-checkpoint.ts
+++ b/packages/service-core/src/storage/write-checkpoint.ts
@@ -55,6 +55,8 @@ export type ManagedWriteCheckpointOptions = ManagedWriteCheckpointFilters;
 export type LastWriteCheckpointFilters = CustomWriteCheckpointFilters | ManagedWriteCheckpointFilters;
 
 export interface WriteCheckpointAPI {
+  setWriteCheckpointMode(mode: WriteCheckpointMode): void;
+
   batchCreateCustomWriteCheckpoints(checkpoints: CustomWriteCheckpointOptions[]): Promise<void>;
 
   createCustomWriteCheckpoint(checkpoint: CustomWriteCheckpointOptions): Promise<bigint>;

From 6d0f671de6c9e8207efdf14cd8d5e31f5e4f253b Mon Sep 17 00:00:00 2001
From: Steven Ontong <steven@journeyapps.com>
Date: Wed, 16 Oct 2024 13:42:23 +0200
Subject: [PATCH 03/13] fix tests

---
 packages/service-core/src/storage/MongoBucketStorage.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/service-core/src/storage/MongoBucketStorage.ts b/packages/service-core/src/storage/MongoBucketStorage.ts
index e86425d54..251727a36 100644
--- a/packages/service-core/src/storage/MongoBucketStorage.ts
+++ b/packages/service-core/src/storage/MongoBucketStorage.ts
@@ -416,7 +416,7 @@ export class MongoBucketStorage
         }
         return (await this.storageCache.fetch(doc._id)) ?? null;
       },
-      syncRules: doc
+      syncRules: doc?.content
         ? new MongoPersistedSyncRulesContent(this.db, doc).parsed({
             defaultSchema: ''
           })

From f45b0410cfe54b595cc6daa347e6139452183442 Mon Sep 17 00:00:00 2001
From: Steven Ontong <steven@journeyapps.com>
Date: Wed, 16 Oct 2024 18:23:33 +0200
Subject: [PATCH 04/13] report current write checkpoint mode

---
 packages/service-core/src/storage/MongoBucketStorage.ts   | 4 ++++
 .../src/storage/mongo/MongoWriteCheckpointAPI.ts          | 8 ++++----
 packages/service-core/src/storage/write-checkpoint.ts     | 2 ++
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/packages/service-core/src/storage/MongoBucketStorage.ts b/packages/service-core/src/storage/MongoBucketStorage.ts
index 251727a36..b27a71b53 100644
--- a/packages/service-core/src/storage/MongoBucketStorage.ts
+++ b/packages/service-core/src/storage/MongoBucketStorage.ts
@@ -96,6 +96,10 @@ export class MongoBucketStorage
     });
   }
 
+  get writeCheckpointMode() {
+    return this.writeCheckpointAPI.writeCheckpointMode;
+  }
+
   getInstance(options: PersistedSyncRulesContent): MongoSyncBucketStorage {
     let { id, slot_name } = options;
     if ((typeof id as any) == 'bigint') {
diff --git a/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts b/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts
index d466173f5..aa66b6f28 100644
--- a/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts
+++ b/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts
@@ -24,7 +24,7 @@ export class MongoWriteCheckpointAPI implements WriteCheckpointAPI {
     this._mode = options.mode;
   }
 
-  get mode() {
+  get writeCheckpointMode() {
     return this._mode;
   }
 
@@ -59,9 +59,9 @@ export class MongoWriteCheckpointAPI implements WriteCheckpointAPI {
   }
 
   async createManagedWriteCheckpoint(checkpoint: ManagedWriteCheckpointOptions): Promise<bigint> {
-    if (this.mode !== WriteCheckpointMode.MANAGED) {
+    if (this.writeCheckpointMode !== WriteCheckpointMode.MANAGED) {
       throw new framework.errors.ValidationError(
-        `Creating a managed Write Checkpoint when the current Write Checkpoint mode is set to "${this.mode}"`
+        `Attempting to create a managed Write Checkpoint when the current Write Checkpoint mode is set to "${this.writeCheckpointMode}"`
       );
     }
 
@@ -84,7 +84,7 @@ export class MongoWriteCheckpointAPI implements WriteCheckpointAPI {
   }
 
   async lastWriteCheckpoint(filters: LastWriteCheckpointFilters): Promise<bigint | null> {
-    switch (this.mode) {
+    switch (this.writeCheckpointMode) {
       case WriteCheckpointMode.CUSTOM:
         if (false == 'sync_rules_id' in filters) {
           throw new framework.errors.ValidationError(`Sync rules ID is required for custom Write Checkpoint filtering`);
diff --git a/packages/service-core/src/storage/write-checkpoint.ts b/packages/service-core/src/storage/write-checkpoint.ts
index 0a45dbffd..3a9abd216 100644
--- a/packages/service-core/src/storage/write-checkpoint.ts
+++ b/packages/service-core/src/storage/write-checkpoint.ts
@@ -55,6 +55,8 @@ export type ManagedWriteCheckpointOptions = ManagedWriteCheckpointFilters;
 export type LastWriteCheckpointFilters = CustomWriteCheckpointFilters | ManagedWriteCheckpointFilters;
 
 export interface WriteCheckpointAPI {
+  readonly writeCheckpointMode: WriteCheckpointMode;
+
   setWriteCheckpointMode(mode: WriteCheckpointMode): void;
 
   batchCreateCustomWriteCheckpoints(checkpoints: CustomWriteCheckpointOptions[]): Promise<void>;

From c65820ac235c585e553d41036607888d320b27b2 Mon Sep 17 00:00:00 2001
From: Steven Ontong <steven@journeyapps.com>
Date: Thu, 17 Oct 2024 15:47:41 +0200
Subject: [PATCH 05/13] cleanup

---
 packages/service-core/src/storage/BucketStorage.ts      | 2 +-
 packages/service-core/src/storage/MongoBucketStorage.ts | 6 +-----
 2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/packages/service-core/src/storage/BucketStorage.ts b/packages/service-core/src/storage/BucketStorage.ts
index 14d95fdd6..8d7df60af 100644
--- a/packages/service-core/src/storage/BucketStorage.ts
+++ b/packages/service-core/src/storage/BucketStorage.ts
@@ -124,7 +124,7 @@ export interface ActiveCheckpoint {
 
   getBucketStorage(): Promise<SyncRulesBucketStorage | null>;
 
-  syncRules: PersistedSyncRules | null;
+  syncRules: PersistedSyncRulesContent | null;
 }
 
 export interface StorageMetrics {
diff --git a/packages/service-core/src/storage/MongoBucketStorage.ts b/packages/service-core/src/storage/MongoBucketStorage.ts
index b27a71b53..8b44e34a3 100644
--- a/packages/service-core/src/storage/MongoBucketStorage.ts
+++ b/packages/service-core/src/storage/MongoBucketStorage.ts
@@ -420,11 +420,7 @@ export class MongoBucketStorage
         }
         return (await this.storageCache.fetch(doc._id)) ?? null;
       },
-      syncRules: doc?.content
-        ? new MongoPersistedSyncRulesContent(this.db, doc).parsed({
-            defaultSchema: ''
-          })
-        : null
+      syncRules: doc ? new MongoPersistedSyncRulesContent(this.db, doc) : null
     } satisfies ActiveCheckpoint;
   }
 

From eb94c0f54ea3eeee167c8dc26e589ef4848e706d Mon Sep 17 00:00:00 2001
From: Steven Ontong <steven@journeyapps.com>
Date: Fri, 18 Oct 2024 09:57:04 +0200
Subject: [PATCH 06/13] changeset version does not run postversion script

---
 packages/sync-rules/package.json | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/packages/sync-rules/package.json b/packages/sync-rules/package.json
index bb942b1e8..727188bb6 100644
--- a/packages/sync-rules/package.json
+++ b/packages/sync-rules/package.json
@@ -15,10 +15,9 @@
   "type": "module",
   "scripts": {
     "clean": "rm -r ./dist && tsc -b --clean",
-    "build": "tsc -b",
+    "build:tsc": "tsc -b",
+    "build": "pnpm build:tsc && node scripts/compile-schema.js",
     "build:tests": "tsc -b test/tsconfig.json",
-    "compile:schema": "pnpm build && node scripts/compile-schema.js",
-    "postversion": "pnpm compile:schema",
     "test": "vitest"
   },
   "dependencies": {

From 83cb22b7e3747bbb11bce845670b0dc1cae4e773 Mon Sep 17 00:00:00 2001
From: Steven Ontong <steven@journeyapps.com>
Date: Fri, 18 Oct 2024 10:28:42 +0200
Subject: [PATCH 07/13] fix docker build

---
 service/Dockerfile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/service/Dockerfile b/service/Dockerfile
index 715931b11..d6641555e 100644
--- a/service/Dockerfile
+++ b/service/Dockerfile
@@ -29,6 +29,7 @@ COPY packages/jpgwire/src packages/jpgwire/src/
 COPY packages/jpgwire/ca packages/jpgwire/ca/
 COPY packages/jsonbig/src packages/jsonbig/src/
 COPY packages/sync-rules/src packages/sync-rules/src/
+COPY packages/sync-rules/scripts packages/sync-rules/scripts/
 COPY packages/rsocket-router/src packages/rsocket-router/src/
 COPY packages/types/src packages/types/src/
 

From e969c615d0d33ab00f4af6ec749046cb8f658287 Mon Sep 17 00:00:00 2001
From: Steven Ontong <steven@journeyapps.com>
Date: Mon, 21 Oct 2024 16:56:30 +0200
Subject: [PATCH 08/13] move write checkpoint methods to sync bucket storage

---
 .../src/routes/endpoints/checkpointing.ts     |  9 ++-
 .../service-core/src/storage/BucketStorage.ts | 18 ++---
 .../src/storage/MongoBucketStorage.ts         | 72 +++----------------
 .../service-core/src/storage/StorageEngine.ts | 26 +------
 .../src/storage/StorageProvider.ts            | 10 +--
 .../src/storage/mongo/MongoBucketBatch.ts     |  4 +-
 .../src/storage/mongo/MongoStorageProvider.ts |  3 +-
 .../storage/mongo/MongoSyncBucketStorage.ts   | 53 ++++++++++++--
 .../storage/mongo/MongoWriteCheckpointAPI.ts  | 11 +--
 .../src/storage/write-checkpoint.ts           | 40 +++++++----
 10 files changed, 111 insertions(+), 135 deletions(-)

diff --git a/packages/service-core/src/routes/endpoints/checkpointing.ts b/packages/service-core/src/routes/endpoints/checkpointing.ts
index 0cfd2dc12..b95dc703b 100644
--- a/packages/service-core/src/routes/endpoints/checkpointing.ts
+++ b/packages/service-core/src/routes/endpoints/checkpointing.ts
@@ -1,6 +1,7 @@
 import { logger, router, schema } from '@powersync/lib-services-framework';
 import * as t from 'ts-codec';
 
+import * as framework from '@powersync/lib-services-framework';
 import * as util from '../../util/util-index.js';
 import { authUser } from '../auth.js';
 import { routeDefinition } from '../router.js';
@@ -63,7 +64,13 @@ export const writeCheckpoint2 = routeDefinition({
       storageEngine: { activeBucketStorage }
     } = service_context;
 
-    const writeCheckpoint = await activeBucketStorage.createManagedWriteCheckpoint({
+    const active = await activeBucketStorage.getActiveSyncRulesContent();
+    if (!active) {
+      throw new framework.errors.ValidationError(`Cannot create Write Checkpoint since no sync rules are active.`);
+    }
+
+    using syncBucketStorage = activeBucketStorage.getInstance(active);
+    const writeCheckpoint = await syncBucketStorage.createManagedWriteCheckpoint({
       user_id: full_user_id,
       heads: { '1': currentCheckpoint }
     });
diff --git a/packages/service-core/src/storage/BucketStorage.ts b/packages/service-core/src/storage/BucketStorage.ts
index 61b376be0..edaa226a9 100644
--- a/packages/service-core/src/storage/BucketStorage.ts
+++ b/packages/service-core/src/storage/BucketStorage.ts
@@ -12,16 +12,15 @@ import * as util from '../util/util-index.js';
 import { ReplicationEventPayload } from './ReplicationEventPayload.js';
 import { SourceEntityDescriptor } from './SourceEntity.js';
 import { SourceTable } from './SourceTable.js';
-import { BatchedCustomWriteCheckpointOptions, ReplicaId, WriteCheckpointAPI } from './storage-index.js';
+import { BatchedCustomWriteCheckpointOptions, ReplicaId } from './storage-index.js';
+import { SyncStorageWriteCheckpointAPI } from './write-checkpoint.js';
 
 export interface BucketStorageFactoryListener extends DisposableListener {
   syncStorageCreated: (storage: SyncRulesBucketStorage) => void;
   replicationEvent: (event: ReplicationEventPayload) => void;
 }
 
-export interface BucketStorageFactory
-  extends DisposableObserverClient<BucketStorageFactoryListener>,
-    WriteCheckpointAPI {
+export interface BucketStorageFactory extends DisposableObserverClient<BucketStorageFactoryListener> {
   /**
    * Update sync rules from configuration, if changed.
    */
@@ -90,11 +89,6 @@ export interface BucketStorageFactory
    */
   getActiveCheckpoint(): Promise<ActiveCheckpoint>;
 
-  /**
-   * Yields the latest sync checkpoint.
-   */
-  watchActiveCheckpoint(signal: AbortSignal): AsyncIterable<ActiveCheckpoint>;
-
   /**
    * Yields the latest user write checkpoint whenever the sync checkpoint updates.
    */
@@ -123,8 +117,6 @@ export interface ActiveCheckpoint {
   hasSyncRules(): boolean;
 
   getBucketStorage(): Promise<SyncRulesBucketStorage | null>;
-
-  syncRules: PersistedSyncRulesContent | null;
 }
 
 export interface StorageMetrics {
@@ -213,7 +205,9 @@ export interface SyncRulesBucketStorageListener extends DisposableListener {
   batchStarted: (batch: BucketStorageBatch) => void;
 }
 
-export interface SyncRulesBucketStorage extends DisposableObserverClient<SyncRulesBucketStorageListener> {
+export interface SyncRulesBucketStorage
+  extends DisposableObserverClient<SyncRulesBucketStorageListener>,
+    SyncStorageWriteCheckpointAPI {
   readonly group_id: number;
   readonly slot_name: string;
 
diff --git a/packages/service-core/src/storage/MongoBucketStorage.ts b/packages/service-core/src/storage/MongoBucketStorage.ts
index 46fd1e66b..f3175b915 100644
--- a/packages/service-core/src/storage/MongoBucketStorage.ts
+++ b/packages/service-core/src/storage/MongoBucketStorage.ts
@@ -25,16 +25,7 @@ import { PowerSyncMongo, PowerSyncMongoOptions } from './mongo/db.js';
 import { SyncRuleDocument, SyncRuleState } from './mongo/models.js';
 import { MongoPersistedSyncRulesContent } from './mongo/MongoPersistedSyncRulesContent.js';
 import { MongoSyncBucketStorage } from './mongo/MongoSyncBucketStorage.js';
-import { MongoWriteCheckpointAPI } from './mongo/MongoWriteCheckpointAPI.js';
 import { generateSlotName } from './mongo/util.js';
-import {
-  CustomWriteCheckpointOptions,
-  DEFAULT_WRITE_CHECKPOINT_MODE,
-  LastWriteCheckpointFilters,
-  ManagedWriteCheckpointOptions,
-  WriteCheckpointAPI,
-  WriteCheckpointMode
-} from './write-checkpoint.js';
 
 export interface MongoBucketStorageOptions extends PowerSyncMongoOptions {}
 
@@ -47,10 +38,6 @@ export class MongoBucketStorage
   // TODO: This is still Postgres specific and needs to be reworked
   public readonly slot_name_prefix: string;
 
-  readonly write_checkpoint_mode: WriteCheckpointMode;
-
-  protected readonly writeCheckpointAPI: WriteCheckpointAPI;
-
   private readonly storageCache = new LRUCache<number, MongoSyncBucketStorage>({
     max: 3,
     fetchMethod: async (id) => {
@@ -78,10 +65,6 @@ export class MongoBucketStorage
     db: PowerSyncMongo,
     options: {
       slot_name_prefix: string;
-      /**
-       * Initial Write Checkpoint Mode
-       */
-      write_checkpoint_mode?: WriteCheckpointMode;
     }
   ) {
     super();
@@ -89,15 +72,6 @@ export class MongoBucketStorage
     this.db = db;
     this.session = this.client.startSession();
     this.slot_name_prefix = options.slot_name_prefix;
-    this.write_checkpoint_mode = options.write_checkpoint_mode ?? DEFAULT_WRITE_CHECKPOINT_MODE;
-    this.writeCheckpointAPI = new MongoWriteCheckpointAPI({
-      db,
-      mode: this.write_checkpoint_mode
-    });
-  }
-
-  get writeCheckpointMode() {
-    return this.writeCheckpointAPI.writeCheckpointMode;
   }
 
   getInstance(options: PersistedSyncRulesContent): MongoSyncBucketStorage {
@@ -306,26 +280,6 @@ export class MongoBucketStorage
     });
   }
 
-  async batchCreateCustomWriteCheckpoints(checkpoints: CustomWriteCheckpointOptions[]): Promise<void> {
-    return this.writeCheckpointAPI.batchCreateCustomWriteCheckpoints(checkpoints);
-  }
-
-  setWriteCheckpointMode(mode: WriteCheckpointMode): void {
-    return this.writeCheckpointAPI.setWriteCheckpointMode(mode);
-  }
-
-  async createCustomWriteCheckpoint(options: CustomWriteCheckpointOptions): Promise<bigint> {
-    return this.writeCheckpointAPI.createCustomWriteCheckpoint(options);
-  }
-
-  async createManagedWriteCheckpoint(options: ManagedWriteCheckpointOptions): Promise<bigint> {
-    return this.writeCheckpointAPI.createManagedWriteCheckpoint(options);
-  }
-
-  async lastWriteCheckpoint(filters: LastWriteCheckpointFilters): Promise<bigint | null> {
-    return this.writeCheckpointAPI.lastWriteCheckpoint(filters);
-  }
-
   async getActiveCheckpoint(): Promise<ActiveCheckpoint> {
     const doc = await this.db.sync_rules.findOne(
       {
@@ -436,15 +390,14 @@ export class MongoBucketStorage
           return null;
         }
         return (await this.storageCache.fetch(doc._id)) ?? null;
-      },
-      syncRules: doc ? new MongoPersistedSyncRulesContent(this.db, doc) : null
+      }
     } satisfies ActiveCheckpoint;
   }
 
   /**
    * Instance-wide watch on the latest available checkpoint (op_id + lsn).
    */
-  private async *_watchActiveCheckpoint(signal: AbortSignal): AsyncIterable<ActiveCheckpoint> {
+  private async *watchActiveCheckpoint(signal: AbortSignal): AsyncIterable<ActiveCheckpoint> {
     const pipeline: mongo.Document[] = [
       {
         $match: {
@@ -457,8 +410,7 @@ export class MongoBucketStorage
           operationType: 1,
           'fullDocument._id': 1,
           'fullDocument.last_checkpoint': 1,
-          'fullDocument.last_checkpoint_lsn': 1,
-          'fullDocument.content': 1
+          'fullDocument.last_checkpoint_lsn': 1
         }
       }
     ];
@@ -480,8 +432,7 @@ export class MongoBucketStorage
           projection: {
             _id: 1,
             last_checkpoint: 1,
-            last_checkpoint_lsn: 1,
-            content: 1
+            last_checkpoint_lsn: 1
           }
         }
       );
@@ -542,16 +493,9 @@ export class MongoBucketStorage
 
   // Nothing is done here until a subscriber starts to iterate
   private readonly sharedIter = new sync.BroadcastIterable((signal) => {
-    return this._watchActiveCheckpoint(signal);
+    return this.watchActiveCheckpoint(signal);
   });
 
-  /**
-   * Watch changes to the active sync rules and checkpoint.
-   */
-  watchActiveCheckpoint(signal: AbortSignal): AsyncIterable<ActiveCheckpoint> {
-    return wrapWithAbort(this.sharedIter, signal);
-  }
-
   /**
    * User-specific watch on the latest checkpoint and/or write checkpoint.
    */
@@ -568,12 +512,14 @@ export class MongoBucketStorage
       // 1. checkpoint (op_id) changes.
       // 2. write checkpoint changes for the specific user
       const bucketStorage = await cp.getBucketStorage();
+      if (!bucketStorage) {
+        continue;
+      }
 
       const lsnFilters: Record<string, string> = lsn ? { 1: lsn } : {};
 
-      const currentWriteCheckpoint = await this.lastWriteCheckpoint({
+      const currentWriteCheckpoint = await bucketStorage.lastWriteCheckpoint({
         user_id,
-        sync_rules_id: bucketStorage?.group_id,
         heads: {
           ...lsnFilters
         }
diff --git a/packages/service-core/src/storage/StorageEngine.ts b/packages/service-core/src/storage/StorageEngine.ts
index bdafeb240..a6639211a 100644
--- a/packages/service-core/src/storage/StorageEngine.ts
+++ b/packages/service-core/src/storage/StorageEngine.ts
@@ -1,17 +1,12 @@
 import { DisposableListener, DisposableObserver, logger } from '@powersync/lib-services-framework';
 import { ResolvedPowerSyncConfig } from '../util/util-index.js';
 import { BucketStorageFactory } from './BucketStorage.js';
-import { ActiveStorage, BucketStorageProvider, StorageSettings } from './StorageProvider.js';
-import { DEFAULT_WRITE_CHECKPOINT_MODE } from './write-checkpoint.js';
+import { ActiveStorage, BucketStorageProvider } from './StorageProvider.js';
 
 export type StorageEngineOptions = {
   configuration: ResolvedPowerSyncConfig;
 };
 
-export const DEFAULT_STORAGE_SETTINGS: StorageSettings = {
-  writeCheckpointMode: DEFAULT_WRITE_CHECKPOINT_MODE
-};
-
 export interface StorageEngineListener extends DisposableListener {
   storageActivated: (storage: BucketStorageFactory) => void;
 }
@@ -20,11 +15,9 @@ export class StorageEngine extends DisposableObserver<StorageEngineListener> {
   // TODO: This will need to revisited when we actually support multiple storage providers.
   private storageProviders: Map<string, BucketStorageProvider> = new Map();
   private currentActiveStorage: ActiveStorage | null = null;
-  private _activeSettings: StorageSettings;
 
   constructor(private options: StorageEngineOptions) {
     super();
-    this._activeSettings = DEFAULT_STORAGE_SETTINGS;
   }
 
   get activeBucketStorage(): BucketStorageFactory {
@@ -39,20 +32,6 @@ export class StorageEngine extends DisposableObserver<StorageEngineListener> {
     return this.currentActiveStorage;
   }
 
-  get activeSettings(): StorageSettings {
-    return { ...this._activeSettings };
-  }
-
-  updateSettings(settings: Partial<StorageSettings>) {
-    if (this.currentActiveStorage) {
-      throw new Error(`Storage is already active, settings cannot be modified.`);
-    }
-    this._activeSettings = {
-      ...this._activeSettings,
-      ...settings
-    };
-  }
-
   /**
    * Register a provider which generates a {@link BucketStorageFactory}
    * given the matching config specified in the loaded {@link ResolvedPowerSyncConfig}
@@ -65,8 +44,7 @@ export class StorageEngine extends DisposableObserver<StorageEngineListener> {
     logger.info('Starting Storage Engine...');
     const { configuration } = this.options;
     this.currentActiveStorage = await this.storageProviders.get(configuration.storage.type)!.getStorage({
-      resolvedConfig: configuration,
-      ...this.activeSettings
+      resolvedConfig: configuration
     });
     this.iterateListeners((cb) => cb.storageActivated?.(this.activeBucketStorage));
     logger.info(`Successfully activated storage: ${configuration.storage.type}.`);
diff --git a/packages/service-core/src/storage/StorageProvider.ts b/packages/service-core/src/storage/StorageProvider.ts
index 7c730fb4b..385a042fd 100644
--- a/packages/service-core/src/storage/StorageProvider.ts
+++ b/packages/service-core/src/storage/StorageProvider.ts
@@ -1,6 +1,5 @@
 import * as util from '../util/util-index.js';
 import { BucketStorageFactory } from './BucketStorage.js';
-import { WriteCheckpointMode } from './write-checkpoint.js';
 
 export interface ActiveStorage {
   storage: BucketStorageFactory;
@@ -12,14 +11,7 @@ export interface ActiveStorage {
   tearDown(): Promise<boolean>;
 }
 
-/**
- * Settings which can be modified by various modules in their initialization.
- */
-export interface StorageSettings {
-  writeCheckpointMode: WriteCheckpointMode;
-}
-
-export interface GetStorageOptions extends StorageSettings {
+export interface GetStorageOptions {
   // TODO: This should just be the storage config. Update once the slot name prefix coupling has been removed from the storage
   resolvedConfig: util.ResolvedPowerSyncConfig;
 }
diff --git a/packages/service-core/src/storage/mongo/MongoBucketBatch.ts b/packages/service-core/src/storage/mongo/MongoBucketBatch.ts
index f0f95cd4e..3a4f38453 100644
--- a/packages/service-core/src/storage/mongo/MongoBucketBatch.ts
+++ b/packages/service-core/src/storage/mongo/MongoBucketBatch.ts
@@ -12,7 +12,7 @@ import {
   SaveOptions
 } from '../BucketStorage.js';
 import { SourceTable } from '../SourceTable.js';
-import { CustomWriteCheckpointOptions } from '../write-checkpoint.js';
+import { BatchedCustomWriteCheckpointOptions, CustomWriteCheckpointOptions } from '../write-checkpoint.js';
 import { PowerSyncMongo } from './db.js';
 import { CurrentBucket, CurrentDataDocument, SourceKey, SyncRuleDocument } from './models.js';
 import { MongoIdSequence } from './MongoIdSequence.js';
@@ -83,7 +83,7 @@ export class MongoBucketBatch extends DisposableObserver<BucketBatchStorageListe
     this.sync_rules = sync_rules;
   }
 
-  addCustomWriteCheckpoint(checkpoint: CustomWriteCheckpointOptions): void {
+  addCustomWriteCheckpoint(checkpoint: BatchedCustomWriteCheckpointOptions): void {
     this.write_checkpoint_batch.push({
       ...checkpoint,
       sync_rules_id: this.group_id
diff --git a/packages/service-core/src/storage/mongo/MongoStorageProvider.ts b/packages/service-core/src/storage/mongo/MongoStorageProvider.ts
index ef16900eb..b4e84f206 100644
--- a/packages/service-core/src/storage/mongo/MongoStorageProvider.ts
+++ b/packages/service-core/src/storage/mongo/MongoStorageProvider.ts
@@ -19,8 +19,7 @@ export class MongoStorageProvider implements BucketStorageProvider {
     return {
       storage: new MongoBucketStorage(database, {
         // TODO currently need the entire resolved config due to this
-        slot_name_prefix: resolvedConfig.slot_name_prefix,
-        write_checkpoint_mode: options.writeCheckpointMode
+        slot_name_prefix: resolvedConfig.slot_name_prefix
       }),
       shutDown: () => client.close(),
       tearDown: () => {
diff --git a/packages/service-core/src/storage/mongo/MongoSyncBucketStorage.ts b/packages/service-core/src/storage/mongo/MongoSyncBucketStorage.ts
index e4b57788e..829ab6ba8 100644
--- a/packages/service-core/src/storage/mongo/MongoSyncBucketStorage.ts
+++ b/packages/service-core/src/storage/mongo/MongoSyncBucketStorage.ts
@@ -2,7 +2,8 @@ import { SqliteJsonRow, SqliteJsonValue, SqlSyncRules } from '@powersync/service
 import * as bson from 'bson';
 import * as mongo from 'mongodb';
 
-import { DisposableObserver } from '@powersync/lib-services-framework';
+import { DisposableObserver, logger } from '@powersync/lib-services-framework';
+import * as timers from 'timers/promises';
 import * as db from '../../db/db-index.js';
 import * as util from '../../util/util-index.js';
 import {
@@ -26,13 +27,19 @@ import {
 import { ChecksumCache, FetchPartialBucketChecksum, PartialChecksum, PartialChecksumMap } from '../ChecksumCache.js';
 import { MongoBucketStorage } from '../MongoBucketStorage.js';
 import { SourceTable } from '../SourceTable.js';
+import {
+  BatchedCustomWriteCheckpointOptions,
+  ManagedWriteCheckpointOptions,
+  SyncStorageLastWriteCheckpointFilters,
+  WriteCheckpointAPI,
+  WriteCheckpointMode
+} from '../write-checkpoint.js';
 import { PowerSyncMongo } from './db.js';
 import { BucketDataDocument, BucketDataKey, SourceKey, SyncRuleState } from './models.js';
 import { MongoBucketBatch } from './MongoBucketBatch.js';
 import { MongoCompactor } from './MongoCompactor.js';
+import { MongoWriteCheckpointAPI } from './MongoWriteCheckpointAPI.js';
 import { BSON_DESERIALIZE_OPTIONS, idPrefixFilter, mapOpEntry, readSingleBatch, serializeLookup } from './util.js';
-import { logger } from '@powersync/lib-services-framework';
-import * as timers from 'timers/promises';
 
 export class MongoSyncBucketStorage
   extends DisposableObserver<SyncRulesBucketStorageListener>
@@ -46,15 +53,53 @@ export class MongoSyncBucketStorage
   });
 
   private parsedSyncRulesCache: SqlSyncRules | undefined;
+  private writeCheckpointAPI: WriteCheckpointAPI;
 
   constructor(
     public readonly factory: MongoBucketStorage,
     public readonly group_id: number,
     private readonly sync_rules: PersistedSyncRulesContent,
-    public readonly slot_name: string
+    public readonly slot_name: string,
+    writeCheckpointMode: WriteCheckpointMode = WriteCheckpointMode.MANAGED
   ) {
     super();
     this.db = factory.db;
+    this.writeCheckpointAPI = new MongoWriteCheckpointAPI({
+      db: this.db,
+      mode: writeCheckpointMode
+    });
+  }
+
+  get writeCheckpointMode() {
+    return this.writeCheckpointAPI.writeCheckpointMode;
+  }
+
+  setWriteCheckpointMode(mode: WriteCheckpointMode): void {
+    this.writeCheckpointAPI.setWriteCheckpointMode(mode);
+  }
+
+  batchCreateCustomWriteCheckpoints(checkpoints: BatchedCustomWriteCheckpointOptions[]): Promise<void> {
+    return this.writeCheckpointAPI.batchCreateCustomWriteCheckpoints(
+      checkpoints.map((checkpoint) => ({ ...checkpoint, sync_rules_id: this.group_id }))
+    );
+  }
+
+  createCustomWriteCheckpoint(checkpoint: BatchedCustomWriteCheckpointOptions): Promise<bigint> {
+    return this.writeCheckpointAPI.createCustomWriteCheckpoint({
+      ...checkpoint,
+      sync_rules_id: this.group_id
+    });
+  }
+
+  createManagedWriteCheckpoint(checkpoint: ManagedWriteCheckpointOptions): Promise<bigint> {
+    return this.writeCheckpointAPI.createManagedWriteCheckpoint(checkpoint);
+  }
+
+  lastWriteCheckpoint(filters: SyncStorageLastWriteCheckpointFilters): Promise<bigint | null> {
+    return this.writeCheckpointAPI.lastWriteCheckpoint({
+      ...filters,
+      sync_rules_id: this.group_id
+    });
   }
 
   getParsedSyncRules(options: ParseSyncRulesOptions): SqlSyncRules {
diff --git a/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts b/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts
index aa66b6f28..46b4266b9 100644
--- a/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts
+++ b/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts
@@ -37,11 +37,12 @@ export class MongoWriteCheckpointAPI implements WriteCheckpointAPI {
   }
 
   async createCustomWriteCheckpoint(options: CustomWriteCheckpointOptions): Promise<bigint> {
-    /**
-     * Allow creating custom checkpoints even if the current mode is not `custom`.
-     * There might be a state where the next sync rules rely on replicating custom
-     * write checkpoints, but the current active sync rules uses managed checkpoints.
-     */
+    if (this.writeCheckpointMode !== WriteCheckpointMode.CUSTOM) {
+      throw new framework.errors.ValidationError(
+        `Creating a custom Write Checkpoint when the current Write Checkpoint mode is set to "${this.writeCheckpointMode}"`
+      );
+    }
+
     const { checkpoint, user_id, sync_rules_id } = options;
     const doc = await this.db.custom_write_checkpoints.findOneAndUpdate(
       {
diff --git a/packages/service-core/src/storage/write-checkpoint.ts b/packages/service-core/src/storage/write-checkpoint.ts
index 3a9abd216..5fce0b18f 100644
--- a/packages/service-core/src/storage/write-checkpoint.ts
+++ b/packages/service-core/src/storage/write-checkpoint.ts
@@ -26,19 +26,19 @@ export interface CustomWriteCheckpointFilters extends BaseWriteCheckpointIdentif
   sync_rules_id: number;
 }
 
-export interface CustomWriteCheckpointOptions extends CustomWriteCheckpointFilters {
+export interface BatchedCustomWriteCheckpointOptions extends BaseWriteCheckpointIdentifier {
   /**
    * A supplied incrementing Write Checkpoint number
    */
   checkpoint: bigint;
 }
 
-/**
- * Options for creating a custom Write Checkpoint in a batch.
- * A {@link BucketStorageBatch} is already associated with a Sync Rules instance.
- * The `sync_rules_id` is not required here.
- */
-export type BatchedCustomWriteCheckpointOptions = Omit<CustomWriteCheckpointOptions, 'sync_rules_id'>;
+export interface CustomWriteCheckpointOptions extends BatchedCustomWriteCheckpointOptions {
+  /**
+   * Sync rules which were active when this checkpoint was created.
+   */
+  sync_rules_id: number;
+}
 
 /**
  * Managed Write Checkpoints are a mapping of User ID to replication HEAD
@@ -52,19 +52,33 @@ export interface ManagedWriteCheckpointFilters extends BaseWriteCheckpointIdenti
 
 export type ManagedWriteCheckpointOptions = ManagedWriteCheckpointFilters;
 
+export type SyncStorageLastWriteCheckpointFilters = BaseWriteCheckpointIdentifier | ManagedWriteCheckpointFilters;
 export type LastWriteCheckpointFilters = CustomWriteCheckpointFilters | ManagedWriteCheckpointFilters;
 
-export interface WriteCheckpointAPI {
+export interface BaseWriteCheckpointAPI {
   readonly writeCheckpointMode: WriteCheckpointMode;
-
   setWriteCheckpointMode(mode: WriteCheckpointMode): void;
+  createManagedWriteCheckpoint(checkpoint: ManagedWriteCheckpointOptions): Promise<bigint>;
+}
 
-  batchCreateCustomWriteCheckpoints(checkpoints: CustomWriteCheckpointOptions[]): Promise<void>;
+/**
+ * Write Checkpoint API to be used in conjunction with a {@link SyncRulesBucketStorage}.
+ * This storage corresponds with a set of sync rules. These APIs don't require specifying a
+ * sync rules id.
+ */
+export interface SyncStorageWriteCheckpointAPI extends BaseWriteCheckpointAPI {
+  batchCreateCustomWriteCheckpoints(checkpoints: BatchedCustomWriteCheckpointOptions[]): Promise<void>;
+  createCustomWriteCheckpoint(checkpoint: BatchedCustomWriteCheckpointOptions): Promise<bigint>;
+  lastWriteCheckpoint(filters: SyncStorageLastWriteCheckpointFilters): Promise<bigint | null>;
+}
 
+/**
+ * Write Checkpoint API which is interfaced directly with the storage layer. This requires
+ * sync rules identifiers for custom write checkpoints.
+ */
+export interface WriteCheckpointAPI extends BaseWriteCheckpointAPI {
+  batchCreateCustomWriteCheckpoints(checkpoints: CustomWriteCheckpointOptions[]): Promise<void>;
   createCustomWriteCheckpoint(checkpoint: CustomWriteCheckpointOptions): Promise<bigint>;
-
-  createManagedWriteCheckpoint(checkpoint: ManagedWriteCheckpointOptions): Promise<bigint>;
-
   lastWriteCheckpoint(filters: LastWriteCheckpointFilters): Promise<bigint | null>;
 }
 

From 380ff8145f61f74dff9299d2a7f5e8b889277556 Mon Sep 17 00:00:00 2001
From: Steven Ontong <steven@journeyapps.com>
Date: Mon, 21 Oct 2024 17:00:29 +0200
Subject: [PATCH 09/13] Rename WriteCheckPointAPI file

---
 .../src/storage/{write-checkpoint.ts => WriteCheckpointAPI.ts}    | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename packages/service-core/src/storage/{write-checkpoint.ts => WriteCheckpointAPI.ts} (100%)

diff --git a/packages/service-core/src/storage/write-checkpoint.ts b/packages/service-core/src/storage/WriteCheckpointAPI.ts
similarity index 100%
rename from packages/service-core/src/storage/write-checkpoint.ts
rename to packages/service-core/src/storage/WriteCheckpointAPI.ts

From 093c5a6a26669720d90b2bb4b39387b06fb3e2f9 Mon Sep 17 00:00:00 2001
From: Steven Ontong <steven@journeyapps.com>
Date: Mon, 21 Oct 2024 17:00:40 +0200
Subject: [PATCH 10/13] updates from rename

---
 packages/service-core/src/storage/BucketStorage.ts            | 2 +-
 packages/service-core/src/storage/mongo/MongoBucketBatch.ts   | 2 +-
 .../service-core/src/storage/mongo/MongoSyncBucketStorage.ts  | 2 +-
 .../service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts | 2 +-
 packages/service-core/src/storage/storage-index.ts            | 4 ++--
 5 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/packages/service-core/src/storage/BucketStorage.ts b/packages/service-core/src/storage/BucketStorage.ts
index edaa226a9..446362a5a 100644
--- a/packages/service-core/src/storage/BucketStorage.ts
+++ b/packages/service-core/src/storage/BucketStorage.ts
@@ -13,7 +13,7 @@ import { ReplicationEventPayload } from './ReplicationEventPayload.js';
 import { SourceEntityDescriptor } from './SourceEntity.js';
 import { SourceTable } from './SourceTable.js';
 import { BatchedCustomWriteCheckpointOptions, ReplicaId } from './storage-index.js';
-import { SyncStorageWriteCheckpointAPI } from './write-checkpoint.js';
+import { SyncStorageWriteCheckpointAPI } from './WriteCheckpointAPI.js';
 
 export interface BucketStorageFactoryListener extends DisposableListener {
   syncStorageCreated: (storage: SyncRulesBucketStorage) => void;
diff --git a/packages/service-core/src/storage/mongo/MongoBucketBatch.ts b/packages/service-core/src/storage/mongo/MongoBucketBatch.ts
index 3a4f38453..c24a04999 100644
--- a/packages/service-core/src/storage/mongo/MongoBucketBatch.ts
+++ b/packages/service-core/src/storage/mongo/MongoBucketBatch.ts
@@ -12,7 +12,7 @@ import {
   SaveOptions
 } from '../BucketStorage.js';
 import { SourceTable } from '../SourceTable.js';
-import { BatchedCustomWriteCheckpointOptions, CustomWriteCheckpointOptions } from '../write-checkpoint.js';
+import { BatchedCustomWriteCheckpointOptions, CustomWriteCheckpointOptions } from '../WriteCheckpointAPI.js';
 import { PowerSyncMongo } from './db.js';
 import { CurrentBucket, CurrentDataDocument, SourceKey, SyncRuleDocument } from './models.js';
 import { MongoIdSequence } from './MongoIdSequence.js';
diff --git a/packages/service-core/src/storage/mongo/MongoSyncBucketStorage.ts b/packages/service-core/src/storage/mongo/MongoSyncBucketStorage.ts
index 829ab6ba8..9243c0107 100644
--- a/packages/service-core/src/storage/mongo/MongoSyncBucketStorage.ts
+++ b/packages/service-core/src/storage/mongo/MongoSyncBucketStorage.ts
@@ -33,7 +33,7 @@ import {
   SyncStorageLastWriteCheckpointFilters,
   WriteCheckpointAPI,
   WriteCheckpointMode
-} from '../write-checkpoint.js';
+} from '../WriteCheckpointAPI.js';
 import { PowerSyncMongo } from './db.js';
 import { BucketDataDocument, BucketDataKey, SourceKey, SyncRuleState } from './models.js';
 import { MongoBucketBatch } from './MongoBucketBatch.js';
diff --git a/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts b/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts
index 46b4266b9..bbcebb0de 100644
--- a/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts
+++ b/packages/service-core/src/storage/mongo/MongoWriteCheckpointAPI.ts
@@ -7,7 +7,7 @@ import {
   ManagedWriteCheckpointOptions,
   WriteCheckpointAPI,
   WriteCheckpointMode
-} from '../write-checkpoint.js';
+} from '../WriteCheckpointAPI.js';
 import { PowerSyncMongo } from './db.js';
 
 export type MongoCheckpointAPIOptions = {
diff --git a/packages/service-core/src/storage/storage-index.ts b/packages/service-core/src/storage/storage-index.ts
index b58576639..231bb3849 100644
--- a/packages/service-core/src/storage/storage-index.ts
+++ b/packages/service-core/src/storage/storage-index.ts
@@ -5,6 +5,7 @@ export * from './SourceEntity.js';
 export * from './SourceTable.js';
 export * from './StorageEngine.js';
 
+export * from './mongo/config.js';
 export * from './mongo/db.js';
 export * from './mongo/models.js';
 export * from './mongo/MongoBucketBatch.js';
@@ -17,5 +18,4 @@ export * from './mongo/MongoSyncRulesLock.js';
 export * from './mongo/OperationBatch.js';
 export * from './mongo/PersistedBatch.js';
 export * from './mongo/util.js';
-export * from './mongo/config.js';
-export * from './write-checkpoint.js';
+export * from './WriteCheckpointAPI.js';

From 93d9191058e8a89e083ce1da44706142dfa767ba Mon Sep 17 00:00:00 2001
From: Steven Ontong <steven@journeyapps.com>
Date: Mon, 21 Oct 2024 17:03:24 +0200
Subject: [PATCH 11/13] rename variable

---
 packages/service-core/src/routes/endpoints/checkpointing.ts | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/packages/service-core/src/routes/endpoints/checkpointing.ts b/packages/service-core/src/routes/endpoints/checkpointing.ts
index b95dc703b..3ce913ad2 100644
--- a/packages/service-core/src/routes/endpoints/checkpointing.ts
+++ b/packages/service-core/src/routes/endpoints/checkpointing.ts
@@ -64,12 +64,12 @@ export const writeCheckpoint2 = routeDefinition({
       storageEngine: { activeBucketStorage }
     } = service_context;
 
-    const active = await activeBucketStorage.getActiveSyncRulesContent();
-    if (!active) {
+    const activeSyncRules = await activeBucketStorage.getActiveSyncRulesContent();
+    if (!activeSyncRules) {
       throw new framework.errors.ValidationError(`Cannot create Write Checkpoint since no sync rules are active.`);
     }
 
-    using syncBucketStorage = activeBucketStorage.getInstance(active);
+    using syncBucketStorage = activeBucketStorage.getInstance(activeSyncRules);
     const writeCheckpoint = await syncBucketStorage.createManagedWriteCheckpoint({
       user_id: full_user_id,
       heads: { '1': currentCheckpoint }

From ba682a460ae6bd80c099672ef0a58bb89df64885 Mon Sep 17 00:00:00 2001
From: Steven Ontong <steven@journeyapps.com>
Date: Mon, 21 Oct 2024 17:20:32 +0200
Subject: [PATCH 12/13] add changeset

---
 .changeset/slow-stingrays-kiss.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/slow-stingrays-kiss.md

diff --git a/.changeset/slow-stingrays-kiss.md b/.changeset/slow-stingrays-kiss.md
new file mode 100644
index 000000000..a93126de7
--- /dev/null
+++ b/.changeset/slow-stingrays-kiss.md
@@ -0,0 +1,5 @@
+---
+'@powersync/service-core': minor
+---
+
+Moved Write Checkpoint APIs to SyncBucketStorage

From 28fb524472727661d15b298f777d733d410e1ec5 Mon Sep 17 00:00:00 2001
From: Steven Ontong <steven@journeyapps.com>
Date: Mon, 21 Oct 2024 17:38:00 +0200
Subject: [PATCH 13/13] fix typo

---
 packages/service-core/src/storage/WriteCheckpointAPI.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/service-core/src/storage/WriteCheckpointAPI.ts b/packages/service-core/src/storage/WriteCheckpointAPI.ts
index 5fce0b18f..d38ac3979 100644
--- a/packages/service-core/src/storage/WriteCheckpointAPI.ts
+++ b/packages/service-core/src/storage/WriteCheckpointAPI.ts
@@ -3,7 +3,7 @@ export enum WriteCheckpointMode {
    * Raw mappings of `user_id` to `write_checkpoint`s should
    * be supplied for each set of sync rules.
    */
-  CUSTOM = 'manual',
+  CUSTOM = 'custom',
   /**
    * Write checkpoints are stored as a mapping of `user_id` plus
    * replication HEAD (lsn in Postgres) to an automatically generated