3 files changed, 11 insertions, 1 deletions
diff --git a/packages/order-watcher/src/order_watcher/event_watcher.ts b/packages/order-watcher/src/order_watcher/event_watcher.ts
index 08ecf81cb..38ba8101e 100644
--- a/packages/order-watcher/src/order_watcher/event_watcher.ts
+++ b/packages/order-watcher/src/order_watcher/event_watcher.ts
@@ -27,13 +27,16 @@ export class EventWatcher {
     private _pollingIntervalMs: number;
     private _stateLayer: BlockParamLiteral;
     private _isVerbose: boolean;
+    private _blockRetention: number;
     constructor(
         web3Wrapper: Web3Wrapper,
         pollingIntervalIfExistsMs: undefined | number,
         stateLayer: BlockParamLiteral = BlockParamLiteral.Latest,
+        blockRetention: number,
         isVerbose: boolean,
     ) {
         this._isVerbose = isVerbose;
+        this._blockRetention = blockRetention;
         this._web3Wrapper = web3Wrapper;
         this._stateLayer = stateLayer;
         this._pollingIntervalMs = _.isUndefined(pollingIntervalIfExistsMs)
@@ -69,6 +72,9 @@ export class EventWatcher {
             this._web3Wrapper.getBlockAsync.bind(this._web3Wrapper, this._stateLayer),
             this._web3Wrapper.getLogsAsync.bind(this._web3Wrapper, eventFilter),
             this._onBlockAndLogStreamerError.bind(this),
+            {
+                blockRetention: this._blockRetention,
+            },
         );
         const catchAllLogFilter = {};
         this._blockAndLogStreamerIfExists.addLogFilter(catchAllLogFilter);
diff --git a/packages/order-watcher/src/order_watcher/order_watcher.ts b/packages/order-watcher/src/order_watcher/order_watcher.ts
index b09ba8d9d..2fe012593 100644
--- a/packages/order-watcher/src/order_watcher/order_watcher.ts
+++ b/packages/order-watcher/src/order_watcher/order_watcher.ts
@@ -61,6 +61,7 @@ interface OrderStateByOrderHash {
 
 // tslint:disable-next-line:custom-no-magic-numbers
 const DEFAULT_CLEANUP_JOB_INTERVAL_MS = 1000 * 60 * 60; // 1h
+const DEFAULT_BLOCK_RETENTION = 100;
 
 /**
  * This class includes all the functionality related to watching a set of orders
@@ -94,7 +95,8 @@ export class OrderWatcher {
         const stateLayer =
             _.isUndefined(config) || _.isUndefined(config.stateLayer) ? BlockParamLiteral.Latest : config.stateLayer;
         const isVerbose = !_.isUndefined(config) && !_.isUndefined(config.isVerbose) ? config.isVerbose : false;
-        this._eventWatcher = new EventWatcher(this._web3Wrapper, pollingIntervalIfExistsMs, stateLayer, isVerbose);
+        const blockRetention = !_.isUndefined(config) && !_.isUndefined(config.blockRetention) ? config.blockRetention : DEFAULT_BLOCK_RETENTION;
+        this._eventWatcher = new EventWatcher(this._web3Wrapper, pollingIntervalIfExistsMs, stateLayer, blockRetention, isVerbose);
         this._balanceAndProxyAllowanceLazyStore = new BalanceAndProxyAllowanceLazyStore(
             this._contractWrappers.token,
             stateLayer,
diff --git a/packages/order-watcher/src/types.ts b/packages/order-watcher/src/types.ts
index 63e4e7848..e9b8626b6 100644
--- a/packages/order-watcher/src/types.ts
+++ b/packages/order-watcher/src/types.ts
@@ -14,6 +14,7 @@ export type EventWatcherCallback = (err: null | Error, log?: LogEntryEvent) => v
  * of an orders expiration. Default=0.
  * cleanupJobIntervalMs: How often to run a cleanup job which revalidates all the orders. Default=1hr.
  * stateLayer: Optional blockchain state layer OrderWatcher will monitor for new events. Default=latest.
+ * blockRetention: The numbers of blocks to retain in-memory, in order to handle block-reorgs. Default=100.
  */
 export interface OrderWatcherConfig {
     stateLayer: BlockParamLiteral;
@@ -22,6 +23,7 @@ export interface OrderWatcherConfig {
     expirationMarginMs?: number;
     cleanupJobIntervalMs?: number;
     isVerbose?: boolean;
+    blockRetention?: number;
 }
 
 export type OnOrderStateChangeCallback = (err: Error | null, orderState?: OrderState) => void;