move refs/pman over to owncloud/ocis/ocis/pkg/runtime

ocis/pkg/runtime/watcher/watcher.go

@@ -0,0 +1,57 @@
+package watcher
+
+import (
+	golog "log"
+	"os"
+
+	"github.com/owncloud/ocis/ocis/pkg/runtime/log"
+	"github.com/owncloud/ocis/ocis/pkg/runtime/process"
+	"github.com/rs/zerolog"
+)
+
+// Watcher watches a process and sends messages using channels.
+type Watcher struct {
+	log zerolog.Logger
+}
+
+// NewWatcher initializes a watcher.
+func NewWatcher() Watcher {
+	return Watcher{
+		log: log.NewLogger(log.WithPretty(true)),
+	}
+}
+
+// Follow a process until it dies. If restart is enabled, a new fork of the original process will be automatically spawned.
+func (w *Watcher) Follow(pe process.ProcEntry, followerChan chan process.ProcEntry, restart bool) {
+	state := make(chan *os.ProcessState, 1)
+
+	w.log.Debug().Str("package", "watcher").Msgf("watching %v", pe.Extension)
+	go func() {
+		ps, err := watch(pe.Pid)
+		if err != nil {
+			golog.Fatal(err)
+		}
+
+		state <- ps
+	}()
+
+	go func() {
+		select {
+		case status := <-state:
+			w.log.Info().Str("package", "watcher").Msgf("%v exited with: %v", pe.Extension, status)
+			if restart {
+				followerChan <- pe
+			}
+		}
+	}()
+}
+
+// watch a process by its pid. This operation blocks.
+func watch(pid int) (*os.ProcessState, error) {
+	p, err := os.FindProcess(pid)
+	if err != nil {
+		return nil, err
+	}
+
+	return p.Wait()
+}