feat(ref-imp): only allow DB upgrade on observer node

* fix(ref-imp): added index to operation store to support CosmosDB 4.0
* feat(ref-imp): only allow DB upgrade on Observer nodes

lib/bitcoin/BitcoinProcessor.ts

@@ -214,13 +214,12 @@ export default class BitcoinProcessor {
       return;
     }
 
-    // Throw if attempting to run old code on new DB.
+    // Throw if attempting to downgrade.
     if (actualDbVersion !== undefined && semver.lt(expectedDbVersion, actualDbVersion)) {
       Logger.error(
-        // eslint-disable-next-line max-len
-        LogColor.red(`Running code dependent on DB version ${LogColor.green(expectedDbVersion)} on newer DB version ${LogColor.green(actualDbVersion)} is not supported.`)
+        LogColor.red(`Downgrading DB from version ${LogColor.green(actualDbVersion)} to  ${LogColor.green(expectedDbVersion)} is not allowed.`)
       );
-      throw new SidetreeError(ErrorCode.RunningOlderCodeOnNewerDatabaseUnsupported);
+      throw new SidetreeError(ErrorCode.DatabaseDowngradeNotAllowed);
     }
 
     // Add DB upgrade code below.

lib/bitcoin/ErrorCode.ts

@@ -19,7 +19,7 @@ export default {
   LockResolverTransactionIsNotPayingToScript: 'lock_resolver_transaction_is_not_paying_to_script',
   LockResolverTransactionNotConfirmed: 'lock_resolver_transaction_not_confirmed',
   LockResolverTransactionNotFound: 'lock_resolver_transaction_not_found',
-  RunningOlderCodeOnNewerDatabaseUnsupported: 'running_older_code_on_newer_database_unsupported',
+  DatabaseDowngradeNotAllowed: 'database_downgrade_not_allowed',
   ValueTimeLockInPendingState: 'value_time_lock_in_pending_state',
   VersionManagerVersionStringNotFound: 'version_manager_version_string_not_found'
 };

lib/core/Core.ts

@@ -162,21 +162,26 @@ export default class Core {
   }
 
   private async upgradeDatabaseIfNeeded () {
-    const expectedDbVersion = '1.0.0';
+    // If this node is not the active Observer node, do not perform DB upgrade.
+    // Since only one active Observer is supported, this ensures only one node is performing the DB upgrade.
+    if (this.config.observingIntervalInSeconds === 0) {
+      return;
+    }
+
+    const expectedDbVersion = '1.0.1';
     const savedServiceState = await this.serviceStateStore.get();
     const actualDbVersion = savedServiceState.databaseVersion;
 
     if (expectedDbVersion === actualDbVersion) {
       return;
     }
 
-    // Throw if attempting to run old code on new DB.
+    // Throw if attempting to downgrade.
     if (actualDbVersion !== undefined && semver.lt(expectedDbVersion, actualDbVersion)) {
       Logger.error(
-        // eslint-disable-next-line max-len
-        LogColor.red(`Running code dependent on DB version ${LogColor.green(expectedDbVersion)} on newer DB version ${LogColor.green(actualDbVersion)} is not supported.`)
+        LogColor.red(`Downgrading DB from version ${LogColor.green(actualDbVersion)} to  ${LogColor.green(expectedDbVersion)} is not allowed.`)
       );
-      throw new SidetreeError(ErrorCode.RunningOlderCodeOnNewerDatabaseUnsupported);
+      throw new SidetreeError(ErrorCode.DatabaseDowngradeNotAllowed);
     }
 
     // Add DB upgrade code below.

lib/core/ErrorCode.ts

@@ -11,7 +11,7 @@ export default {
   BlockchainReadResponseBodyNotJson: 'blockchain_read_response_body_not_json',
   BlockchainReadResponseNotOk: 'blockchain_read_response_not_ok',
   BlockchainWriteUnexpectedError: 'blockchain_write_unexpected_error',
-  RunningOlderCodeOnNewerDatabaseUnsupported: 'running_older_code_on_newer_database_unsupported',
+  DatabaseDowngradeNotAllowed: 'database_downgrade_not_allowed',
   VersionManagerVersionStringNotFound: 'version_manager_version_string_not_found',
   VersionManagerVersionMetadataIncorrectType: 'version_manager_version_metadata_incorrect_type'
 };

lib/core/MongoDbOperationStore.ts

@@ -36,6 +36,8 @@ export default class MongoDbOperationStore extends MongoDbStore implements IOper
     await this.collection.createIndex({ didSuffix: 1, txnNumber: 1, opIndex: 1, type: 1 }, { unique: true });
     // The query in `get() method needs a corresponding composite index in some cloud-based services (CosmosDB 4.0) that supports MongoDB driver.
     await this.collection.createIndex({ didSuffix: 1, txnNumber: 1, opIndex: 1 }, { unique: true });
+    // The query in `get() method needs a non-composite index on `didSuffix` in some cloud-based services (CosmosDB 4.0) to allow efficient queries.
+    await this.collection.createIndex({ didSuffix: 1 }, { unique: false });
   }
 
   public async insertOrReplace (operations: AnchoredOperationModel[]): Promise<void> {

tests/bitcoin/BitcoinProcessor.spec.ts

@@ -1885,7 +1885,7 @@ describe('BitcoinProcessor', () => {
 
       JasmineSidetreeErrorValidator.expectSidetreeErrorToBeThrownAsync(
         () => (bitcoinProcessor as any).upgradeDatabaseIfNeeded(),
-        ErrorCode.RunningOlderCodeOnNewerDatabaseUnsupported
+        ErrorCode.DatabaseDowngradeNotAllowed
       );
     });
   });

tests/core/Core.spec.ts

@@ -184,11 +184,23 @@ describe('Core', async () => {
     beforeEach(() => {
     });
 
+    it('should not perform upgrade if the node is not an active Observer node.', async () => {
+      const config = Object.assign({}, testConfig);
+      config.observingIntervalInSeconds = 0; // Force disabling of Observer.
+      const core = new Core(config, testVersionConfig, mockCas);
+
+      const serviceStateStorePutSpy = spyOn(core['serviceStateStore'], 'put');
+      await (core as any).upgradeDatabaseIfNeeded();
+
+      // Verify that upgrade path was NOT invoked.
+      expect(serviceStateStorePutSpy).not.toHaveBeenCalled();
+    });
+
     it('should not perform upgrade if saved database version is the same as the expected database version.', async () => {
       const core = new Core(testConfig, testVersionConfig, mockCas);
 
       // Simulate that the saved database version is the same as the expected database version.
-      spyOn(core['serviceStateStore'], 'get').and.returnValue(Promise.resolve({ databaseVersion: '1.0.0' }));
+      spyOn(core['serviceStateStore'], 'get').and.returnValue(Promise.resolve({ databaseVersion: '1.0.1' }));
 
       const serviceStateStorePutSpy = spyOn(core['serviceStateStore'], 'put');
       await (core as any).upgradeDatabaseIfNeeded();
@@ -216,7 +228,7 @@ describe('Core', async () => {
       expect(unresolvableTransactionStoreClearCollectionSpy).toHaveBeenCalled();
       expect(transactionStoreClearCollectionSpy).toHaveBeenCalled();
       expect(operationStoreCreateIndexSpy).toHaveBeenCalled();
-      expect(serviceStateStorePutSpy).toHaveBeenCalledWith({ databaseVersion: '1.0.0' });
+      expect(serviceStateStorePutSpy).toHaveBeenCalledWith({ databaseVersion: '1.0.1' });
     });
 
     it('should throw if attempting to run older code on newer DB.', async () => {
@@ -227,7 +239,7 @@ describe('Core', async () => {
 
       JasmineSidetreeErrorValidator.expectSidetreeErrorToBeThrownAsync(
         () => (core as any).upgradeDatabaseIfNeeded(),
-        ErrorCode.RunningOlderCodeOnNewerDatabaseUnsupported
+        ErrorCode.DatabaseDowngradeNotAllowed
       );
     });
   });