dtl: config for starting L1 block number

Adds the config option `DATA_TRANSPORT_LAYER_STARTING_L1_BLOCK_NUMBER`
or `--starting-l1-blocknumber` that allows for the user to specify
the L1 blocknumber to begin syncing from. This prevents users from
syncing old batches from a previous regenesis.

.changeset/tough-coins-poke.md

+---
+'@eth-optimism/data-transport-layer': patch
+---
+
+Add config for L1 start height to allow for syncing specifically after a regenesis. Using the auto detect method will not work with the regenesis scheme of using the same AddressManager

packages/data-transport-layer/src/services/l1-ingestion/service.ts

@@ -152,20 +152,31 @@ export class L1IngestionService extends BaseService<L1IngestionServiceOptions> {
       this.options.addressManager
     )
 
-    const startingL1BlockNumber = await this.state.db.getStartingL1Block()
-    if (startingL1BlockNumber) {
-      this.state.startingL1BlockNumber = startingL1BlockNumber
+    // Look up in the database for an indexed starting L1 block
+    let startingL1BlockNumber = await this.state.db.getStartingL1Block()
+    // If there isn't an indexed starting L1 block, that means we should pull it
+    // from config and then fallback to discovering it
+    if (startingL1BlockNumber === null || startingL1BlockNumber === undefined) {
+      if (this.options.l1StartHeight !== null && this.options.l1StartHeight !== undefined) {
+        startingL1BlockNumber = this.options.l1StartHeight
       } else {
         this.logger.info(
           'Attempting to find an appropriate L1 block height to begin sync...'
         )
-      this.state.startingL1BlockNumber = await this._findStartingL1BlockNumber()
+        startingL1BlockNumber = await this._findStartingL1BlockNumber()
+      }
+    }
+
+    if (!startingL1BlockNumber) {
+      throw new Error('Cannot find starting L1 block number')
+    }
+
     this.logger.info('Starting sync', {
-        startingL1BlockNumber: this.state.startingL1BlockNumber,
+      startingL1BlockNumber,
     })
 
+    this.state.startingL1BlockNumber = startingL1BlockNumber
     await this.state.db.setStartingL1Block(this.state.startingL1BlockNumber)
-    }
 
     // Store the total number of submitted transactions so the server can tell clients if we're
     // done syncing or not

packages/data-transport-layer/src/services/main/service.ts

@@ -35,6 +35,7 @@ export interface L1DataTransportServiceOptions {
   sentryTraceRate?: number
   defaultBackend: string
   l1GasPriceBackend: string
+  l1StartHeight?: number
 }
 
 const optionSettings = {

packages/data-transport-layer/src/services/run.ts

@@ -47,6 +47,7 @@ type ethNetwork = 'mainnet' | 'kovan' | 'goerli'
       ),
       defaultBackend: config.str('default-backend', 'l1'),
       l1GasPriceBackend: config.str('l1-gas-price-backend', 'l1'),
+      l1StartHeight: config.uint('l1-start-height'),
       useSentry: config.bool('use-sentry', false),
       sentryDsn: config.str('sentry-dsn'),
       sentryTraceRate: config.ufloat('sentry-trace-rate', 0.05),