#249- only import 'level' when it's actually used (#254)

i.e. if a developer provides their own `createLevelDatabase` then we will use that instead of `'level'`

in order to support this for both node and browser, we need to switch to using dynamic `import` (instead of `require`, as that's not defined for node when `"type": "module"`)

most of this commit is changing sync logic to `async` for that purpose (though it also allows for more flexibility when providing a custom `createLevelDatabase`)

README.md

@@ -3,7 +3,7 @@
 # Decentralized Web Node (DWN) SDK
 
 Code Coverage
-![Statements](https://img.shields.io/badge/statements-94.84%25-brightgreen.svg?style=flat) ![Branches](https://img.shields.io/badge/branches-94.07%25-brightgreen.svg?style=flat) ![Functions](https://img.shields.io/badge/functions-92.78%25-brightgreen.svg?style=flat) ![Lines](https://img.shields.io/badge/lines-94.84%25-brightgreen.svg?style=flat)
+![Statements](https://img.shields.io/badge/statements-94.86%25-brightgreen.svg?style=flat) ![Branches](https://img.shields.io/badge/branches-93.59%25-brightgreen.svg?style=flat) ![Functions](https://img.shields.io/badge/functions-92.82%25-brightgreen.svg?style=flat) ![Lines](https://img.shields.io/badge/lines-94.86%25-brightgreen.svg?style=flat)
 
 ## Introduction
 

src/store/blockstore-level.ts

@@ -22,16 +22,16 @@ export class BlockstoreLevel implements Blockstore {
    * the {@link https://developer.mozilla.org/en-US/docs/Web/API/IDBDatabase IDBDatabase}
    * to be opened.
    */
-  constructor(location: string, config: BlockstoreLevelConfig = {}) {
+  constructor(config: BlockstoreLevelConfig) {
     this.config = {
       createLevelDatabase,
       ...config
     };
-
-    this.db = this.config.createLevelDatabase<string, Uint8Array>(location, { keyEncoding: 'utf8', valueEncoding: 'binary' });
   }
 
   async open(): Promise<void> {
+    await this.createLevelDatabase();
+
     while (this.db.status === 'opening' || this.db.status === 'closing') {
       await sleep(200);
     }
@@ -52,6 +52,10 @@ export class BlockstoreLevel implements Blockstore {
    * releases all file handles and locks held by the underlying db.
    */
   async close(): Promise<void> {
+    if (!this.db) {
+      return;
+    }
+
     while (this.db.status === 'opening' || this.db.status === 'closing') {
       await sleep(200);
     }
@@ -63,23 +67,30 @@ export class BlockstoreLevel implements Blockstore {
     return this.db.close();
   }
 
-  partition(name: string): BlockstoreLevel {
-    return new BlockstoreLevel('', {
-      createLevelDatabase: <K, V>(_location: string, options?: LevelDatabaseOptions<K, V>): LevelDatabase<K, V> => {
+  async partition(name: string): Promise<BlockstoreLevel> {
+    await this.createLevelDatabase();
+
+    return new BlockstoreLevel({
+      location            : '',
+      createLevelDatabase : async <K, V>(_location: string, options?: LevelDatabaseOptions<K, V>): Promise<LevelDatabase<K, V>> => {
         return this.db.sublevel(name, options);
       }
     });
   }
 
-  put(key: CID, val: Uint8Array, options?: Options): Promise<void> {
+  async put(key: CID, val: Uint8Array, options?: Options): Promise<void> {
     options?.signal?.throwIfAborted();
 
+    await abortOr(options?.signal, this.createLevelDatabase());
+
     return abortOr(options?.signal, this.db.put(key.toString(), val));
   }
 
   async get(key: CID, options?: Options): Promise<Uint8Array> {
     options?.signal?.throwIfAborted();
 
+    await abortOr(options?.signal, this.createLevelDatabase());
+
     try {
       const val = await abortOr(options?.signal, this.db.get(key.toString()));
       return val;
@@ -97,9 +108,11 @@ export class BlockstoreLevel implements Blockstore {
     return !! await this.get(key, options);
   }
 
-  delete(key: CID, options?: Options): Promise<void> {
+  async delete(key: CID, options?: Options): Promise<void> {
     options?.signal?.throwIfAborted();
 
+    await abortOr(options?.signal, this.createLevelDatabase());
+
     return abortOr(options?.signal, this.db.del(key.toString()));
   }
 
@@ -127,6 +140,10 @@ export class BlockstoreLevel implements Blockstore {
     }
   }
 
+  private async createLevelDatabase(): Promise<void> {
+    this.db ??= await this.config.createLevelDatabase<string, Uint8Array>(this.config.location, { keyEncoding: 'utf8', valueEncoding: 'binary' });
+  }
+
   /**
    * deletes all entries
    */
@@ -148,5 +165,6 @@ export class BlockstoreLevel implements Blockstore {
 }
 
 type BlockstoreLevelConfig = {
+  location: string,
   createLevelDatabase?: typeof createLevelDatabase,
 };

src/store/create-level.ts

@@ -1,11 +1,12 @@
 import type { AbstractDatabaseOptions, AbstractLevel } from 'abstract-level';
 
-import { Level } from 'level';
-
 export type LevelDatabase<K, V> = AbstractLevel<string | Buffer | Uint8Array, K, V>;
 
 export type LevelDatabaseOptions<K, V> = AbstractDatabaseOptions<K, V>;
 
-export function createLevelDatabase<K, V>(location: string, options?: LevelDatabaseOptions<K, V>): LevelDatabase<K, V> {
+export async function createLevelDatabase<K, V>(location: string, options?: LevelDatabaseOptions<K, V>): Promise<LevelDatabase<K, V>> {
+  // Only import `'level'` when it's actually necessary (i.e. only when the default `createLevelDatabase` is used).
+  // Overriding `createLevelDatabase` will prevent this from happening.
+  const { Level } = await import('level');
   return new Level(location, options);
 }

src/store/data-store-level.ts

@@ -22,8 +22,9 @@ export class DataStoreLevel implements DataStore {
       ...config
     };
 
-    this.blockstore = new BlockstoreLevel(this.config.blockstoreLocation, {
-      createLevelDatabase: this.config.createLevelDatabase,
+    this.blockstore = new BlockstoreLevel({
+      location            : this.config.blockstoreLocation,
+      createLevelDatabase : this.config.createLevelDatabase,
     });
   }
 
@@ -36,7 +37,7 @@ export class DataStoreLevel implements DataStore {
   }
 
   async put(tenant: string, recordId: string, dataStream: Readable): Promise<string> {
-    const partition = this.blockstore.partition(tenant);
+    const partition = await this.blockstore.partition(tenant);
 
     const asyncDataBlocks = importer([{ content: dataStream }], partition, { cidVersion: 1 });
 
@@ -49,7 +50,7 @@ export class DataStoreLevel implements DataStore {
   }
 
   public async get(tenant: string, recordId: string, dataCid: string): Promise<Readable | undefined> {
-    const partition = this.blockstore.partition(tenant);
+    const partition = await this.blockstore.partition(tenant);
 
     const cid = CID.parse(dataCid);
     const bytes = await partition.get(cid);
@@ -77,7 +78,7 @@ export class DataStoreLevel implements DataStore {
   }
 
   public async has(tenant: string, recordId: string, dataCid: string): Promise<boolean> {
-    const partition = this.blockstore.partition(tenant);
+    const partition = await this.blockstore.partition(tenant);
 
     const cid = CID.parse(dataCid);
     const rootBlockBytes = await partition.get(cid);
@@ -86,7 +87,7 @@ export class DataStoreLevel implements DataStore {
   }
 
   public async delete(tenant: string, recordId: string, dataCid: string): Promise<void> {
-    const partition = this.blockstore.partition(tenant);
+    const partition = await this.blockstore.partition(tenant);
 
     // TODO: Implement data deletion in Records - https://github.com/TBD54566975/dwn-sdk-js/issues/84
     const cid = CID.parse(dataCid);

src/store/message-store-level.ts

@@ -41,8 +41,9 @@ export class MessageStoreLevel implements MessageStore {
       ...config
     };
 
-    this.blockstore = new BlockstoreLevel(this.config.blockstoreLocation, {
-      createLevelDatabase: this.config.createLevelDatabase,
+    this.blockstore = new BlockstoreLevel({
+      location            : this.config.blockstoreLocation,
+      createLevelDatabase : this.config.createLevelDatabase,
     });
   }
 
@@ -64,7 +65,7 @@ export class MessageStoreLevel implements MessageStore {
   async get(tenant: string, cidString: string, options?: Options): Promise<BaseMessage | undefined> {
     options?.signal?.throwIfAborted();
 
-    const partition = this.blockstore.partition(tenant);
+    const partition = await abortOr(options?.signal, this.blockstore.partition(tenant));
 
     const cid = CID.parse(cidString);
     const bytes = await partition.get(cid, options);
@@ -106,7 +107,7 @@ export class MessageStoreLevel implements MessageStore {
   async delete(tenant: string, cidString: string, options?: Options): Promise<void> {
     options?.signal?.throwIfAborted();
 
-    const partition = this.blockstore.partition(tenant);
+    const partition = await abortOr(options?.signal, this.blockstore.partition(tenant));
 
     // TODO: Implement data deletion in Records - https://github.com/TBD54566975/dwn-sdk-js/issues/84
     const cid = CID.parse(cidString);
@@ -124,7 +125,7 @@ export class MessageStoreLevel implements MessageStore {
   ): Promise<void> {
     options?.signal?.throwIfAborted();
 
-    const partition = this.blockstore.partition(tenant);
+    const partition = await abortOr(options?.signal, this.blockstore.partition(tenant));
 
     const encodedMessageBlock = await abortOr(options?.signal, block.encode({ value: message, codec: cbor, hasher: sha256 }));
 

tests/store/message-store.spec.ts

@@ -175,15 +175,16 @@ describe('MessageStoreLevel Tests', () => {
     it('should be called if provided', async () => {
       let called = 0;
 
-      new MessageStoreLevel({
+      const messageStore = new MessageStoreLevel({
         blockstoreLocation : 'TEST-BLOCKSTORE',
         indexLocation      : 'TEST-INDEX',
-        createLevelDatabase<K, V>(location, options?: LevelDatabaseOptions<K, V>): LevelDatabase<K, V> {
+        createLevelDatabase<K, V>(location, options?: LevelDatabaseOptions<K, V>): Promise<LevelDatabase<K, V>> {
           ++called;
           expect(location).to.equal('TEST-BLOCKSTORE');
           return createLevelDatabase(location, options);
         }
       });
+      await messageStore.open();
 
       expect(called).to.equal(1);
     });