improve console output

internal/cmd/pspy.go

@@ -0,0 +1,84 @@
+package cmd
+
+import (
+	"log"
+	"time"
+
+	"github.com/dominicbreuker/pspy/internal/inotify"
+	"github.com/dominicbreuker/pspy/internal/process"
+	"github.com/dominicbreuker/pspy/internal/walker"
+)
+
+const MaxInt = int(^uint(0) >> 1)
+
+func Monitor() {
+	watch([]string{"/tmp"}, nil)
+}
+
+func watch(rdirs, dirs []string) {
+	maxWatchers, err := inotify.WatcherLimit()
+	if err != nil {
+		log.Printf("Can't get inotify watcher limit...: %v\n", err)
+	}
+	log.Printf("Inotify watcher limit: %d (/proc/sys/fs/inotify/max_user_watches)\n", maxWatchers)
+
+	ping := make(chan struct{})
+	in, err := inotify.NewInotify(ping)
+	if err != nil {
+		log.Fatalf("Can't init inotify: %v", err)
+	}
+	defer in.Close()
+
+	for _, dir := range rdirs {
+		addWatchers(dir, MaxInt, in, maxWatchers)
+	}
+	for _, dir := range dirs {
+		addWatchers(dir, 0, in, maxWatchers)
+	}
+
+	log.Printf("Inotify watchers set up: %s\n", in)
+
+	procList := process.NewProcList()
+
+	ticker := time.NewTicker(100 * time.Millisecond)
+
+	for {
+		select {
+		case <-ticker.C:
+			refresh(in, procList)
+		case <-ping:
+			refresh(in, procList)
+		}
+	}
+}
+
+func addWatchers(dir string, depth int, in *inotify.Inotify, maxWatchers int) {
+	dirCh, errCh, doneCh := walker.Walk(dir, depth)
+loop:
+	for {
+		if in.NumWatchers() >= maxWatchers {
+			close(doneCh)
+			break loop
+		}
+		select {
+		case dir, ok := <-dirCh:
+			if !ok {
+				break loop
+			}
+			if err := in.Watch(dir); err != nil {
+				log.Printf("Can't create watcher: %v", err)
+			}
+		case err := <-errCh:
+			log.Printf("Error walking filesystem: %v", err)
+		}
+	}
+}
+
+func refresh(in *inotify.Inotify, pl *process.ProcList) {
+	in.Pause()
+	if err := pl.Refresh(); err != nil {
+		log.Printf("ERROR refreshing process list: %v", err)
+	}
+	time.Sleep(5 * time.Millisecond)
+	in.UnPause()
+}