single anvil instance (#14)

* single anvil instance

* feedback

anvil/anvil.go

@@ -0,0 +1,118 @@
+package anvil
+
+import (
+	"bufio"
+	"context"
+	"errors"
+	"fmt"
+	"os/exec"
+	"sync/atomic"
+
+	"github.com/ethereum/go-ethereum/log"
+)
+
+type Config struct {
+	ChainId uint64
+	Port    uint64
+}
+
+type Anvil struct {
+	log log.Logger
+
+	cfg *Config
+	cmd *exec.Cmd
+
+	resourceCtx    context.Context
+	resourceCancel context.CancelFunc
+
+	stopped   atomic.Bool
+	stoppedCh chan struct{}
+}
+
+func New(log log.Logger, cfg *Config) *Anvil {
+	resCtx, resCancel := context.WithCancel(context.Background())
+	return &Anvil{
+		log:            log,
+		cfg:            cfg,
+		resourceCtx:    resCtx,
+		resourceCancel: resCancel,
+		stoppedCh:      make(chan struct{}, 1),
+	}
+}
+
+func (a *Anvil) Start(ctx context.Context) error {
+	if a.cmd != nil {
+		return errors.New("anvil already started")
+	}
+
+	anvilLog := a.log.New("chain.id", a.cfg.ChainId)
+	anvilLog.Info("starting anvil")
+
+	// Prep args
+	args := []string{
+		"--host", "127.0.0.1",
+		"--chain-id", fmt.Sprintf("%d", a.cfg.ChainId),
+		"--port", fmt.Sprintf("%d", a.cfg.Port),
+	}
+
+	a.cmd = exec.CommandContext(a.resourceCtx, "anvil", args...)
+	go func() {
+		<-ctx.Done()
+		a.resourceCancel()
+	}()
+
+	// Handle stdout/stderr
+	//  - TODO: Figure out best way to dump into logger. Some hex isn't showing appropriately
+	stdout, err := a.cmd.StdoutPipe()
+	if err != nil {
+		return fmt.Errorf("failed to get handle on stdout: %w", err)
+	}
+	stderr, err := a.cmd.StderrPipe()
+	if err != nil {
+		return fmt.Errorf("failed to get handle on stderr: %w", err)
+	}
+	go func() {
+		scanner := bufio.NewScanner(stdout)
+		for scanner.Scan() {
+			anvilLog.Info(scanner.Text())
+		}
+	}()
+	go func() {
+		scanner := bufio.NewScanner(stderr)
+		for scanner.Scan() {
+			anvilLog.Error(scanner.Text())
+		}
+	}()
+
+	// Start anvil
+	if err := a.cmd.Start(); err != nil {
+		return fmt.Errorf("failed to start anvil: %w", err)
+	}
+	go func() {
+		if err := a.cmd.Wait(); err != nil {
+			anvilLog.Error("anvil terminated with an error", "error", err)
+		} else {
+			anvilLog.Info("anvil terminated")
+		}
+		a.stoppedCh <- struct{}{}
+	}()
+
+	return nil
+}
+
+func (a *Anvil) Stop() error {
+	if a.stopped.Load() {
+		return errors.New("already stopped")
+	}
+	if !a.stopped.CompareAndSwap(false, true) {
+		return nil // someone else stopped
+	}
+
+	a.resourceCancel()
+	<-a.stoppedCh
+	return nil
+}
+
+func (a *Anvil) Stopped() bool {
+	return a.stopped.Load()
+}

supersim.go

@@ -3,27 +3,32 @@ package supersim
 import (
 	"context"
 
+	"github.com/ethereum-optimism/supersim/anvil"
+
 	"github.com/ethereum/go-ethereum/log"
 )
 
 type Supersim struct {
 	log log.Logger
+
+	anvil *anvil.Anvil
 }
 
 func NewSupersim(log log.Logger) *Supersim {
-	return &Supersim{log}
+	anvil := anvil.New(log, &anvil.Config{ChainId: 10, Port: 9545})
+	return &Supersim{log, anvil}
 }
 
 func (s *Supersim) Start(ctx context.Context) error {
 	s.log.Info("starting supersim")
-	return nil
+	return s.anvil.Start(ctx)
 }
 
-func (s *Supersim) Stop(ctx context.Context) error {
+func (s *Supersim) Stop(_ context.Context) error {
 	s.log.Info("stopping supersim")
-	return nil
+	return s.anvil.Stop()
 }
 
 func (s *Supersim) Stopped() bool {
-	return false
+	return s.anvil.Stopped()
 }