Break out binary / indexing logic into separate packages

op-chain-ops/cmd/eof-crawler/main.go

+package main
+
+import (
+	"errors"
+	"os"
+
+	"github.com/mattn/go-isatty"
+	"github.com/urfave/cli/v2"
+
+	"github.com/ethereum-optimism/optimism/op-chain-ops/eof"
+	"github.com/ethereum/go-ethereum/log"
+)
+
+func main() {
+	log.Root().SetHandler(log.StreamHandler(os.Stderr, log.TerminalFormat(isatty.IsTerminal(os.Stderr.Fd()))))
+
+	app := &cli.App{
+		Name:  "eof-crawler",
+		Usage: "Scan a Geth database for EOF-prefixed contracts",
+		Flags: []cli.Flag{
+			&cli.StringFlag{
+				Name:  "db-path",
+				Usage: "Path to the geth LevelDB",
+			},
+			&cli.StringFlag{
+				Name:  "out",
+				Value: "eof-contracts.json",
+				Usage: "Path to the output file",
+			},
+		},
+		Action: func(ctx *cli.Context) error {
+			dbPath := ctx.String("db-path")
+			if len(dbPath) == 0 {
+				return errors.New("Must specify a db-path")
+			}
+			out := ctx.String("out")
+
+			eof.IndexEOFContracts(dbPath, out)
+
+			return nil
+		},
+	}
+
+	if err := app.Run(os.Args); err != nil {
+		log.Crit("error indexing state", "err", err)
+	}
+}

op-chain-ops/eof-crawler/README.md → op-chain-ops/eof/README.md

@@ -6,6 +6,6 @@ Simple CLI tool to scan all accounts in a geth LevelDB for contracts that begin
 
 1. Pass the directory of the Geth DB into the tool
 ```sh
-go run eof_crawler.go <db_path>
+go run ./cmd/eof-crawler/main.go --db-path <db_path> [--out <out_file>]
 ```
-2. Once the indexing has completed, an array of all EOF-prefixed contracts will be written to `eof_contracts.json`.
+2. Once the indexing has completed, an array of all EOF-prefixed contracts will be written to `eof_contracts.json` or the designated output file.

op-chain-ops/eof-crawler/eof_crawler.go → op-chain-ops/eof/eof_crawler.go

-package main
+package eof
 
 import (
 	"bytes"
@@ -31,9 +31,11 @@ type Account struct {
 // emptyCodeHash is the known hash of an account with no code.
 var emptyCodeHash = crypto.Keccak256(nil)
 
-func main() {
+// IndexEOFContracts indexes all the EOF contracts in the state trie of the head block
+// for the given db and writes them to a JSON file.
+func IndexEOFContracts(dbPath string, out string) {
 	// Open an existing Ethereum database
-	db, err := rawdb.NewLevelDBDatabase(os.Args[1], 16, 16, "", true)
+	db, err := rawdb.NewLevelDBDatabase(dbPath, 16, 16, "", true)
 	if err != nil {
 		log.Fatalf("Failed to open database: %v", err)
 	}
@@ -126,10 +128,10 @@ func main() {
 	if err != nil {
 		log.Fatalf("Cannot marshal EOF contracts: %v", err)
 	}
-	err = os.WriteFile("eof_contracts.json", file, 0644)
+	err = os.WriteFile(out, file, 0644)
 	if err != nil {
 		log.Fatalf("Failed to write EOF contracts array to file: %v", err)
 	}
 
-	log.Printf("Wrote list of EOF contracts to `eof_contracts.json`")
+	log.Printf("Wrote list of EOF contracts to `%v`", out)
 }