fix: send seedkit progress output to stderr

Allows piping JSON output cleanly: ./seedkit run fragmented -o json | jq

Made-with: Cursor

Author: piotr-iohk

tools/seedkit/cmd/run.go

@@ -53,8 +53,8 @@ var runCmd = &cobra.Command{
 			return fmt.Errorf("backend: %w", err)
 		}
 
-		fmt.Printf("Running scenario: %s\n", s.Name)
-		fmt.Printf("Backend: %s\n\n", label)
+		fmt.Fprintf(os.Stderr, "Running scenario: %s\n", s.Name)
+		fmt.Fprintf(os.Stderr, "Backend: %s\n\n", label)
 
 		if err := b.EnsureFunds(); err != nil {
 			return fmt.Errorf("ensure funds: %w", err)

tools/seedkit/internal/backend/local.go

@@ -7,6 +7,7 @@ import (
 	"io"
 	"net/http"
 	"net/url"
+	"os"
 )
 
 type LocalBackend struct {
@@ -64,7 +65,7 @@ func (b *LocalBackend) EnsureFunds() error {
 	if balance >= 1.0 {
 		return nil
 	}
-	fmt.Println("Mining 101 blocks to generate funds...")
+	fmt.Fprintln(os.Stderr, "Mining 101 blocks to generate funds...")
 	return b.Mine(101)
 }
 

tools/seedkit/internal/scenario/scenario.go

@@ -2,6 +2,7 @@ package scenario
 
 import (
 	"fmt"
+	"os"
 
 	"github.com/synonymdev/bitkit-e2e-tests/tools/seedkit/internal/backend"
 	"github.com/synonymdev/bitkit-e2e-tests/tools/seedkit/internal/wallet"
@@ -63,7 +64,7 @@ func (s *Scenario) Execute(w *wallet.Wallet, b backend.Backend) (*Result, error)
 			return nil, fmt.Errorf("step %d: derive address: %w", i+1, err)
 		}
 
-		fmt.Printf("  [%d/%d] %s: %d sat -> %s\n", i+1, len(s.Steps), step.Description, step.AmountSat, addr)
+		fmt.Fprintf(os.Stderr, "  [%d/%d] %s: %d sat -> %s\n", i+1, len(s.Steps), step.Description, step.AmountSat, addr)
 
 		if err := b.Deposit(addr, step.AmountSat); err != nil {
 			return nil, fmt.Errorf("step %d: deposit: %w", i+1, err)