feat(ref-imp): emitted a couple of events in bitcoin processor

docs/bitcoin.md

@@ -28,3 +28,25 @@ The fund allocated for transaction fees for subsequent re-locking of the initial
 
 > Developer's note:
 This allotted amount is locked together with value time lock for simplicity of re-lock implementation. If this allotted amount is depleted due to subsequent re-locks, the remaining locked amount will be released back to wallet, and a new lock will be created with this allotted amount added to it again.
+
+## Events
+
+### `bitcoin_processor_databases_revert`
+Occurs every time the databases are reverted due to a bitcoin reorg.
+
+Event data:
+```json
+{
+  "blockHeight": "The block height that the databases are reverted to.",
+}
+```
+
+### `bitcoin_processor_observing_loop_failed`
+Occurs every time the bitcoin processor fails an observing loop.
+
+Event data: none
+
+### `bitcoin_processor_observing_loop_success`
+Occurs every time the bitcoin processor successfully completes a processing loop.
+
+Event data: none

lib/bitcoin/BitcoinProcessor.ts

@@ -1,4 +1,5 @@
 import * as timeSpan from 'time-span';
+import { ISidetreeEventEmitter, ISidetreeLogger } from '..';
 import BitcoinBlockDataIterator from './BitcoinBlockDataIterator';
 import BitcoinBlockModel from './models/BitcoinBlockModel';
 import BitcoinClient from './BitcoinClient';
@@ -8,8 +9,9 @@ import BitcoinVersionModel from './models/BitcoinVersionModel';
 import BlockMetadata from './models/BlockMetadata';
 import BlockMetadataWithoutNormalizedFee from './models/BlockMetadataWithoutNormalizedFee';
 import ErrorCode from './ErrorCode';
+import EventCode from './EventCode';
+import EventEmitter from '../common/EventEmitter';
 import IBitcoinConfig from './IBitcoinConfig';
-import { ISidetreeLogger } from '..';
 import LockMonitor from './lock/LockMonitor';
 import LockResolver from './lock/LockResolver';
 import LogColor from '../common/LogColor';
@@ -153,8 +155,9 @@ export default class BitcoinProcessor {
   /**
    * Initializes the Bitcoin processor
    */
-  public async initialize (versionModels: BitcoinVersionModel[], customLogger?: ISidetreeLogger) {
+  public async initialize (versionModels: BitcoinVersionModel[], customLogger?: ISidetreeLogger, customEventEmitter?: ISidetreeEventEmitter) {
     Logger.initialize(customLogger);
+    EventEmitter.initialize(customEventEmitter);
 
     await this.versionManager.initialize(versionModels, this.config, this.blockMetadataStore);
     await this.serviceStateStore.initialize();
@@ -671,7 +674,10 @@ export default class BitcoinProcessor {
       } else {
         await this.processTransactions(startingBlock);
       }
+
+      EventEmitter.emit(EventCode.BitcoinProcessorObservingLoopSuccessful);
     } catch (error) {
+      EventEmitter.emit(EventCode.BitcoinProcessorObservingLoopFailed);
       Logger.error(error);
     } finally {
       this.pollTimeoutId = setTimeout(this.periodicPoll.bind(this), 1000 * interval, interval);
@@ -752,11 +758,15 @@ export default class BitcoinProcessor {
    * @returns A known valid block before the fork. `undefined` if no known valid block can be found.
    */
   private async revertDatabases (): Promise<IBlockInfo | undefined> {
+    Logger.info(`Reverting databases...`);
     const exponentiallySpacedBlocks = await this.blockMetadataStore.lookBackExponentially();
     const lastKnownValidBlock = await this.firstValidBlock(exponentiallySpacedBlocks);
+    const lastKnownValidBlockHeight = lastKnownValidBlock ? lastKnownValidBlock.height : undefined;
 
-    await this.trimDatabasesToBlock(lastKnownValidBlock ? lastKnownValidBlock.height : undefined);
+    Logger.info(LogColor.lightBlue(`Reverting database to ${LogColor.green(lastKnownValidBlockHeight || 'genesis')} block...`));
+    await this.trimDatabasesToBlock(lastKnownValidBlockHeight);
 
+    EventEmitter.emit(EventCode.BitcoinProcessorDatabasesRevert, { blockHeight: lastKnownValidBlockHeight });
     return lastKnownValidBlock;
   }
 

lib/bitcoin/EventCode.ts

@@ -0,0 +1,8 @@
+/**
+ * Event codes used by Bitcoin Processor.
+ */
+export default {
+  BitcoinProcessorDatabasesRevert: 'bitcoin_processor_databases_revert',
+  BitcoinProcessorObservingLoopFailed: 'bitcoin_processor_observing_loop_failed',
+  BitcoinProcessorObservingLoopSuccessful: `bitcoin_processor_observing_loop_successful`
+};