Do nothing on duplicate log insert

- Prevents duplicate key constraint violation from blocking the process
  from moving forward on restart.
- If header_id, log_idx, and tx_idx are the same, we can safely do
  nothing since it's definitely the same log - a reorg would cause the
  original header to be replaced with a new ID.

pkg/contract_watcher/shared/repository/event_repository.go

@@ -128,7 +128,7 @@ func (r *eventRepository) persistHeaderSyncLogs(logs []types.Log, eventInfo type
 		for i := 0; i < el; i++ {
 			pgStr = pgStr + fmt.Sprintf(", $%d", i+6)
 		}
-		pgStr = pgStr + ")"
+		pgStr = pgStr + ") ON CONFLICT DO NOTHING"
 
 		// Add this query to the transaction
 		_, err = tx.Exec(pgStr, data...)

pkg/contract_watcher/shared/repository/event_repository_test.go

@@ -320,17 +320,13 @@ var _ = Describe("Repository", func() {
 				err = hr.AddCheckColumn(event.Name + "_" + con.Address)
 				Expect(err).ToNot(HaveOccurred())
 
-				// Try and fail to persist the same log twice in a single call
-				err = dataStore.PersistLogs([]types.Log{logs[0], logs[0]}, event, con.Address, con.Name)
-				Expect(err).To(HaveOccurred())
-
-				// Successfuly persist the two unique logs
+				// Successfully persist the two unique logs
 				err = dataStore.PersistLogs(logs, event, con.Address, con.Name)
 				Expect(err).ToNot(HaveOccurred())
 
-				// Try and fail to persist the same logs again in separate call
-				err = dataStore.PersistLogs([]types.Log{*log}, event, con.Address, con.Name)
-				Expect(err).To(HaveOccurred())
+				// Try to insert the same logs again
+				err = dataStore.PersistLogs(logs, event, con.Address, con.Name)
+				Expect(err).ToNot(HaveOccurred())
 
 				// Show that no new logs were entered
 				var count int
@@ -339,6 +335,26 @@ var _ = Describe("Repository", func() {
 				Expect(count).To(Equal(2))
 			})
 
+			It("inserts additional log if only some are duplicate", func() {
+				hr := lr.NewHeaderRepository(db)
+				err = hr.AddCheckColumn(event.Name + "_" + con.Address)
+				Expect(err).ToNot(HaveOccurred())
+
+				// Successfully persist first log
+				err = dataStore.PersistLogs([]types.Log{logs[0]}, event, con.Address, con.Name)
+				Expect(err).ToNot(HaveOccurred())
+
+				// Successfully persist second log even though first already persisted
+				err = dataStore.PersistLogs(logs, event, con.Address, con.Name)
+				Expect(err).ToNot(HaveOccurred())
+
+				// Show that both logs were entered
+				var count int
+				err = db.Get(&count, fmt.Sprintf("SELECT COUNT(*) FROM header_%s.transfer_event", constants.TusdContractAddress))
+				Expect(err).ToNot(HaveOccurred())
+				Expect(count).To(Equal(2))
+			})
+
 			It("Fails if the persisted event does not have a corresponding eventID column in the checked_headers table", func() {
 				err = dataStore.PersistLogs(logs, event, con.Address, con.Name)
 				Expect(err).To(HaveOccurred())