Fix/server manager

build/Dockerfile

@@ -271,7 +271,8 @@ apt-get install -y --no-install-recommends \
     libpq5 \
     redis \
     libboost-log1.74.0 \
-    redis-tools
+    redis-tools \
+    procps
 rm -rf /var/lib/apt/lists/*
 EOF
 

cmd/cartesi-rollups-node/services.go

@@ -279,8 +279,8 @@ func newRedis() services.CommandService {
 	return s
 }
 
-func newServerManager() services.CommandService {
-	var s services.CommandService
+func newServerManager() services.ServerManager {
+	var s services.ServerManager
 	s.Name = "server-manager"
 	s.HealthcheckPort = getPort(portOffsetServerManager)
 	s.Path = "server-manager"

internal/services/server-manager.go

@@ -0,0 +1,127 @@
+// (c) Cartesi and individual authors (see AUTHORS)
+// SPDX-License-Identifier: Apache-2.0 (see LICENSE)
+
+package services
+
+import (
+	"context"
+	"fmt"
+	"net"
+	"os/exec"
+	"strconv"
+	"strings"
+	"syscall"
+	"time"
+
+	"github.com/cartesi/rollups-node/internal/config"
+)
+
+// ServerManager is a variation of CommandService used to manually stop
+// the orphaned cartesi-machines left after server-manager exits.
+// For more information, check https://github.com/cartesi/server-manager/issues/18
+type ServerManager struct {
+	// Name that identifies the service.
+	Name string
+
+	// Port used to verify if the service is ready.
+	HealthcheckPort int
+
+	// Path to the service binary.
+	Path string
+
+	// Args to the service binary.
+	Args []string
+
+	// Environment variables.
+	Env []string
+}
+
+const waitDelay = 200 * time.Millisecond
+
+func (s ServerManager) Start(ctx context.Context, ready chan<- struct{}) error {
+	cmd := exec.CommandContext(ctx, s.Path, s.Args...)
+	cmd.Env = s.Env
+	cmd.Stderr = newLineWriter(commandLogger{s.Name})
+	cmd.Stdout = newLineWriter(commandLogger{s.Name})
+	// Without a delay, cmd.Wait() will block forever waiting for the I/O pipes
+	// to be closed
+	cmd.WaitDelay = waitDelay
+	cmd.Cancel = func() error {
+		err := killChildProcesses(cmd.Process.Pid)
+		if err != nil {
+			config.WarningLogger.Println(err)
+		}
+
+		err = cmd.Process.Signal(syscall.SIGTERM)
+		if err != nil {
+			config.WarningLogger.Printf("failed to send SIGTERM to %v: %v\n", s, err)
+		}
+		return err
+	}
+
+	go s.pollTcp(ctx, ready)
+	err := cmd.Run()
+
+	if ctx.Err() != nil {
+		return ctx.Err()
+	}
+	return err
+}
+
+// Blocks until the service is ready or the context is canceled
+func (s ServerManager) pollTcp(ctx context.Context, ready chan<- struct{}) {
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+	for {
+		conn, err := net.Dial("tcp", fmt.Sprintf("0.0.0.0:%v", s.HealthcheckPort))
+		if err == nil {
+			config.DebugLogger.Printf("%s is ready\n", s)
+			conn.Close()
+			ready <- struct{}{}
+			return
+		}
+		select {
+		case <-ctx.Done():
+			return
+		case <-time.After(DefaultPollInterval):
+		}
+	}
+}
+
+func (s ServerManager) String() string {
+	return s.Name
+}
+
+// Kills all child processes spawned by pid
+func killChildProcesses(pid int) error {
+	children, err := getChildrenPid(pid)
+	if err != nil {
+		return fmt.Errorf("failed to get child processes. %v", err)
+	}
+	for _, child := range children {
+		err = syscall.Kill(child, syscall.SIGKILL)
+		if err != nil {
+			return fmt.Errorf("failed to kill child process: %v. %v\n", child, err)
+		}
+	}
+	return nil
+}
+
+// Returns a list of processes whose parent is ppid
+func getChildrenPid(ppid int) ([]int, error) {
+	output, err := exec.Command("pgrep", "-P", fmt.Sprint(ppid)).CombinedOutput()
+	if err != nil {
+		return nil, fmt.Errorf("failed to exec pgrep: %v: %v", err, string(output))
+	}
+
+	var children []int
+	pids := strings.Split(strings.TrimSpace(string(output)), "\n")
+	for _, pid := range pids {
+		childPid, err := strconv.Atoi(pid)
+		if err != nil {
+			return nil, fmt.Errorf("failed to parse pid: %v", err)
+		}
+		children = append(children, childPid)
+	}
+	return children, nil
+}