From 9d5fe4f6a98b30fd73be8259f84fa595ac994a71 Mon Sep 17 00:00:00 2001
From: Valery Piashchynski <piashchynski_valery@hotmail.com>
Date: Thu, 17 Dec 2020 02:34:44 +0300
Subject: huge refactor

---
 pkg/socket/socket_factory.go | 228 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 228 insertions(+)
 create mode 100755 pkg/socket/socket_factory.go

(limited to 'pkg/socket/socket_factory.go')

diff --git a/pkg/socket/socket_factory.go b/pkg/socket/socket_factory.go
new file mode 100755
index 00000000..f721ad66
--- /dev/null
+++ b/pkg/socket/socket_factory.go
@@ -0,0 +1,228 @@
+package socket
+
+import (
+	"context"
+	"net"
+	"os/exec"
+	"sync"
+	"time"
+
+	"github.com/shirou/gopsutil/process"
+	"github.com/spiral/errors"
+	"github.com/spiral/roadrunner/v2/interfaces/worker"
+	"github.com/spiral/roadrunner/v2/internal"
+	workerImpl "github.com/spiral/roadrunner/v2/pkg/worker"
+
+	"github.com/spiral/goridge/v3"
+	"go.uber.org/multierr"
+	"golang.org/x/sync/errgroup"
+)
+
+// Factory connects to external stack using socket server.
+type Factory struct {
+	// listens for incoming connections from underlying processes
+	ls net.Listener
+
+	// relay connection timeout
+	tout time.Duration
+
+	// sockets which are waiting for process association
+	// relays map[int64]*goridge.SocketRelay
+	relays sync.Map
+
+	ErrCh chan error
+}
+
+// todo: review
+
+// NewSocketServer returns Factory attached to a given socket listener.
+// tout specifies for how long factory should serve for incoming relay connection
+func NewSocketServer(ls net.Listener, tout time.Duration) worker.Factory {
+	f := &Factory{
+		ls:     ls,
+		tout:   tout,
+		relays: sync.Map{},
+		ErrCh:  make(chan error, 10),
+	}
+
+	// Be careful
+	// https://github.com/go101/go101/wiki/About-memory-ordering-guarantees-made-by-atomic-operations-in-Go
+	// https://github.com/golang/go/issues/5045
+	go func() {
+		f.ErrCh <- f.listen()
+	}()
+
+	return f
+}
+
+// blocking operation, returns an error
+func (f *Factory) listen() error {
+	errGr := &errgroup.Group{}
+	errGr.Go(func() error {
+		for {
+			conn, err := f.ls.Accept()
+			if err != nil {
+				return err
+			}
+
+			rl := goridge.NewSocketRelay(conn)
+			pid, err := internal.FetchPID(rl)
+			if err != nil {
+				return err
+			}
+
+			f.attachRelayToPid(pid, rl)
+		}
+	})
+
+	return errGr.Wait()
+}
+
+type socketSpawn struct {
+	w   worker.BaseProcess
+	err error
+}
+
+// SpawnWorker creates Process and connects it to appropriate relay or returns error
+func (f *Factory) SpawnWorkerWithContext(ctx context.Context, cmd *exec.Cmd) (worker.BaseProcess, error) {
+	const op = errors.Op("spawn_worker_with_context")
+	c := make(chan socketSpawn)
+	go func() {
+		ctx, cancel := context.WithTimeout(ctx, f.tout)
+		defer cancel()
+		w, err := workerImpl.InitBaseWorker(cmd)
+		if err != nil {
+			c <- socketSpawn{
+				w:   nil,
+				err: err,
+			}
+			return
+		}
+
+		err = w.Start()
+		if err != nil {
+			c <- socketSpawn{
+				w:   nil,
+				err: errors.E(op, err),
+			}
+			return
+		}
+
+		rl, err := f.findRelayWithContext(ctx, w)
+		if err != nil {
+			err = multierr.Combine(
+				err,
+				w.Kill(),
+				w.Wait(),
+			)
+
+			c <- socketSpawn{
+				w:   nil,
+				err: errors.E(op, err),
+			}
+			return
+		}
+
+		w.AttachRelay(rl)
+		w.State().Set(internal.StateReady)
+
+		c <- socketSpawn{
+			w:   w,
+			err: nil,
+		}
+	}()
+
+	select {
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	case res := <-c:
+		if res.err != nil {
+			return nil, res.err
+		}
+
+		return res.w, nil
+	}
+}
+
+func (f *Factory) SpawnWorker(cmd *exec.Cmd) (worker.BaseProcess, error) {
+	const op = errors.Op("spawn_worker")
+	w, err := workerImpl.InitBaseWorker(cmd)
+	if err != nil {
+		return nil, err
+	}
+
+	err = w.Start()
+	if err != nil {
+		return nil, errors.E(op, err)
+	}
+
+	rl, err := f.findRelay(w)
+	if err != nil {
+		err = multierr.Combine(
+			err,
+			w.Kill(),
+			w.Wait(),
+		)
+		return nil, err
+	}
+
+	w.AttachRelay(rl)
+	w.State().Set(internal.StateReady)
+
+	return w, nil
+}
+
+// Close socket factory and underlying socket connection.
+func (f *Factory) Close(ctx context.Context) error {
+	return f.ls.Close()
+}
+
+// waits for Process to connect over socket and returns associated relay of timeout
+func (f *Factory) findRelayWithContext(ctx context.Context, w worker.BaseProcess) (*goridge.SocketRelay, error) {
+	ticker := time.NewTicker(time.Millisecond * 100)
+	for {
+		select {
+		case <-ctx.Done():
+			return nil, ctx.Err()
+		case <-ticker.C:
+			_, err := process.NewProcess(int32(w.Pid()))
+			if err != nil {
+				return nil, err
+			}
+		default:
+			tmp, ok := f.relays.Load(w.Pid())
+			if !ok {
+				continue
+			}
+			return tmp.(*goridge.SocketRelay), nil
+		}
+	}
+}
+
+func (f *Factory) findRelay(w worker.BaseProcess) (*goridge.SocketRelay, error) {
+	const op = errors.Op("find_relay")
+	// poll every 1ms for the relay
+	pollDone := time.NewTimer(f.tout)
+	for {
+		select {
+		case <-pollDone.C:
+			return nil, errors.E(op, errors.Str("relay timeout"))
+		default:
+			tmp, ok := f.relays.Load(w.Pid())
+			if !ok {
+				continue
+			}
+			return tmp.(*goridge.SocketRelay), nil
+		}
+	}
+}
+
+// chan to store relay associated with specific pid
+func (f *Factory) attachRelayToPid(pid int64, relay goridge.Relay) {
+	f.relays.Store(pid, relay)
+}
+
+// deletes relay chan associated with specific pid
+func (f *Factory) removeRelayFromPid(pid int64) {
+	f.relays.Delete(pid)
+}
-- 
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