feat: rollkit rebuild command to update entrypoint (rollkit#1707)

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

- **New Features**
- Introduced a `rebuild` command to the CLI for rebuilding the rollup
entrypoint based on configuration in `rollkit.toml`.

- **Refactor**
- Improved the logic for building and running entrypoint binaries by
introducing a dedicated function to handle the build process.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

---------

Co-authored-by: Javed Khan <tuxcanfly@gmail.com>

cmd/rollkit/commands/intercept.go

@@ -65,6 +65,28 @@ readTOML:
 	return true, runEntrypoint(&rollkitConfig, flags)
 }
 
+func buildEntrypoint(rootDir, entrypointSourceFile string, forceRebuild bool) (string, error) {
+	// The entrypoint binary file is always in the same directory as the rollkit.toml file.
+	entrypointBinaryFile := filepath.Join(rootDir, rollupBinEntrypoint)
+
+	if !cometos.FileExists(entrypointBinaryFile) || forceRebuild {
+		if !cometos.FileExists(entrypointSourceFile) {
+			return "", fmt.Errorf("no entrypoint source file: %s", entrypointSourceFile)
+		}
+
+		// try to build the entrypoint as a go binary
+		buildArgs := []string{"build", "-o", entrypointBinaryFile, entrypointSourceFile}
+		buildCmd := exec.Command("go", buildArgs...) //nolint:gosec
+		buildCmd.Stdout = os.Stdout
+		buildCmd.Stderr = os.Stderr
+		if err := buildCmd.Run(); err != nil {
+			return "", fmt.Errorf("failed to build entrypoint: %w", err)
+		}
+	}
+
+	return entrypointBinaryFile, nil
+}
+
 // RunRollupEntrypoint runs the entrypoint specified in the rollkit.toml configuration file.
 // If the entrypoint is not built, it will build it first. The entrypoint is built
 // in the same directory as the rollkit.toml file. The entrypoint is run with the
@@ -79,22 +101,9 @@ func RunRollupEntrypoint(rollkitConfig *rollconf.TomlConfig, args []string) erro
 		entrypointSourceFile = rollkitConfig.Entrypoint
 	}
 
-	// The entrypoint binary file is always in the same directory as the rollkit.toml file.
-	entrypointBinaryFile := filepath.Join(rollkitConfig.RootDir, rollupBinEntrypoint)
-
-	if !cometos.FileExists(entrypointBinaryFile) {
-		if !cometos.FileExists(entrypointSourceFile) {
-			return fmt.Errorf("no entrypoint file: %s", entrypointSourceFile)
-		}
-
-		// try to build the entrypoint as a go binary
-		buildArgs := []string{"build", "-o", entrypointBinaryFile, entrypointSourceFile}
-		buildCmd := exec.Command("go", buildArgs...) //nolint:gosec
-		buildCmd.Stdout = os.Stdout
-		buildCmd.Stderr = os.Stderr
-		if err := buildCmd.Run(); err != nil {
-			return fmt.Errorf("failed to build entrypoint: %w", err)
-		}
+	entrypointBinaryFilePath, err := buildEntrypoint(rollkitConfig.RootDir, entrypointSourceFile, false)
+	if err != nil {
+		return err
 	}
 
 	var runArgs []string
@@ -105,7 +114,7 @@ func RunRollupEntrypoint(rollkitConfig *rollconf.TomlConfig, args []string) erro
 		runArgs = append(runArgs, "--home", rollkitConfig.Chain.ConfigDir)
 	}
 
-	entrypointCmd := exec.Command(entrypointBinaryFile, runArgs...) //nolint:gosec
+	entrypointCmd := exec.Command(entrypointBinaryFilePath, runArgs...) //nolint:gosec
 	entrypointCmd.Stdout = os.Stdout
 	entrypointCmd.Stderr = os.Stderr
 

cmd/rollkit/commands/rebuild.go

@@ -0,0 +1,27 @@
+package commands
+
+import (
+	"log"
+
+	rollconf "github.com/rollkit/rollkit/config"
+
+	"github.com/spf13/cobra"
+)
+
+// RebuildCmd is a command to rebuild rollup entrypoint
+var RebuildCmd = &cobra.Command{
+	Use:   "rebuild",
+	Short: "Rebuild rollup entrypoint",
+	Long:  "Rebuild rollup entrypoint specified in the rollkit.toml",
+	Run: func(cmd *cobra.Command, args []string) {
+		var err error
+		rollkitConfig, err = rollconf.ReadToml()
+		if err != nil {
+			log.Fatalf("Could not read rollkit.toml file: %s", err)
+		}
+
+		if _, err := buildEntrypoint(rollkitConfig.RootDir, rollkitConfig.Entrypoint, true); err != nil {
+			log.Fatalf("Could not rebuild rollup entrypoint: %s", err)
+		}
+	},
+}

cmd/rollkit/docs/rollkit.md

@@ -23,6 +23,7 @@ If a path is not specified for RKHOME, the rollkit command will create a folder
 
 * [rollkit completion](rollkit_completion.md)	 - Generate the autocompletion script for the specified shell
 * [rollkit docs-gen](rollkit_docs-gen.md)	 - Generate documentation for rollkit CLI
+* [rollkit rebuild](rollkit_rebuild.md)	 - Rebuild rollup entrypoint
 * [rollkit start](rollkit_start.md)	 - Run the rollkit node
 * [rollkit toml](rollkit_toml.md)	 - TOML file operations
 * [rollkit version](rollkit_version.md)	 - Show version info

cmd/rollkit/docs/rollkit_rebuild.md

@@ -0,0 +1,29 @@
+## rollkit rebuild
+
+Rebuild rollup entrypoint
+
+### Synopsis
+
+Rebuild rollup entrypoint specified in the rollkit.toml
+
+```
+rollkit rebuild [flags]
+```
+
+### Options
+
+```
+  -h, --help   help for rebuild
+```
+
+### Options inherited from parent commands
+
+```
+      --home string        directory for config and data (default "HOME/.rollkit")
+      --log_level string   set the log level; default is info. other options include debug, info, error, none (default "info")
+      --trace              print out full stack trace on errors
+```
+
+### SEE ALSO
+
+* [rollkit](rollkit.md)	 - The first sovereign rollup framework that allows you to launch a sovereign, customizable blockchain as easily as a smart contract.

cmd/rollkit/main.go

@@ -21,6 +21,7 @@ func main() {
 		cmd.NewRunNodeCmd(),
 		cmd.VersionCmd,
 		cmd.NewTomlCmd(),
+		cmd.RebuildCmd,
 	)
 
 	// In case there is a rollkit.toml file in the current dir or somewhere up the