Gather file descriptors as process metric

client/app/scripts/utils/string-utils.js

@@ -10,6 +10,13 @@ const formatters = {
     return formatters.metric(obj.value, obj.suffix);
   },
 
+  integer(value) {
+    if (value < 1100 && value >= 0) {
+      return Number(value).toFixed(0);
+    }
+    return formatLargeValue(value);
+  },
+
   number(value) {
     if (value < 1100 && value >= 0) {
       return Number(value).toFixed(2);

probe/process/reporter.go

@@ -9,13 +9,14 @@ import (
 
 // We use these keys in node metadata
 const (
-	PID         = "pid"
-	Name        = "name"
-	PPID        = "ppid"
-	Cmdline     = "cmdline"
-	Threads     = "threads"
-	CPUUsage    = "process_cpu_usage_percent"
-	MemoryUsage = "process_memory_usage_bytes"
+	PID             = "pid"
+	Name            = "name"
+	PPID            = "ppid"
+	Cmdline         = "cmdline"
+	Threads         = "threads"
+	CPUUsage        = "process_cpu_usage_percent"
+	MemoryUsage     = "process_memory_usage_bytes"
+	FileDescriptors = "file_descriptors"
 )
 
 // Reporter generates Reports containing the Process topology.
@@ -84,6 +85,7 @@ func (r *Reporter) processTopology() (report.Topology, error) {
 		}
 
 		node = node.WithMetric(MemoryUsage, report.MakeMetric().Add(now, float64(p.RSSBytes)))
+		node = node.WithMetric(FileDescriptors, report.MakeMetric().Add(now, float64(p.FileDescriptors)))
 
 		t.AddNode(nodeID, node)
 	})

probe/process/walker.go

@@ -4,12 +4,13 @@ import "sync"
 
 // Process represents a single process.
 type Process struct {
-	PID, PPID int
-	Name      string
-	Cmdline   string
-	Threads   int
-	Jiffies   uint64
-	RSSBytes  uint64
+	PID, PPID       int
+	Name            string
+	Cmdline         string
+	Threads         int
+	Jiffies         uint64
+	RSSBytes        uint64
+	FileDescriptors int
 }
 
 // Walker is something that walks the /proc directory

probe/process/walker_linux.go

@@ -62,6 +62,11 @@ func readStats(path string) (ppid, threads int, jiffies, rss uint64, err error)
 	return
 }
 
+func readFileDescriptors(path string) (int, error) {
+	names, err := fs.ReadDirNames(path)
+	return len(names), err
+}
+
 // Walk walks the supplied directory (expecting it to look like /proc)
 // and marshalls the files into instances of Process, which it then
 // passes one-by-one to the supplied function. Walk is only made public
@@ -83,6 +88,11 @@ func (w *walker) Walk(f func(Process, Process)) error {
 			continue
 		}
 
+		fileDescriptors, err := readFileDescriptors(path.Join(w.procRoot, filename, "fd"))
+		if err != nil {
+			continue
+		}
+
 		cmdline, name := "", "(unknown)"
 		if cmdlineBuf, err := cachedReadFile(path.Join(w.procRoot, filename, "cmdline")); err == nil {
 			// like proc, treat name as the first element of command line
@@ -96,13 +106,14 @@ func (w *walker) Walk(f func(Process, Process)) error {
 		}
 
 		f(Process{
-			PID:      pid,
-			PPID:     ppid,
-			Name:     name,
-			Cmdline:  cmdline,
-			Threads:  threads,
-			Jiffies:  jiffies,
-			RSSBytes: rss,
+			PID:             pid,
+			PPID:            ppid,
+			Name:            name,
+			Cmdline:         cmdline,
+			Threads:         threads,
+			Jiffies:         jiffies,
+			RSSBytes:        rss,
+			FileDescriptors: fileDescriptors,
 		}, Process{})
 	}
 

probe/process/walker_linux_test.go

@@ -21,6 +21,7 @@ var mockFS = fs.Dir("",
 				FName:     "stat",
 				FContents: "3 na R 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0",
 			},
+			fs.Dir("fd", fs.File{FName: "0"}, fs.File{FName: "1"}, fs.File{FName: "2"}),
 		),
 		fs.Dir("2",
 			fs.File{
@@ -31,6 +32,7 @@ var mockFS = fs.Dir("",
 				FName:     "stat",
 				FContents: "2 na R 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0",
 			},
+			fs.Dir("fd", fs.File{FName: "1"}, fs.File{FName: "2"}),
 		),
 		fs.Dir("4",
 			fs.File{
@@ -41,6 +43,7 @@ var mockFS = fs.Dir("",
 				FName:     "stat",
 				FContents: "4 na R 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0",
 			},
+			fs.Dir("fd", fs.File{FName: "0"}),
 		),
 		fs.Dir("notapid"),
 		fs.Dir("1",
@@ -52,6 +55,7 @@ var mockFS = fs.Dir("",
 				FName:     "stat",
 				FContents: "1 na R 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0",
 			},
+			fs.Dir("fd"),
 		),
 	),
 )
@@ -61,10 +65,10 @@ func TestWalker(t *testing.T) {
 	defer fs_hook.Restore()
 
 	want := map[int]process.Process{
-		3: {PID: 3, PPID: 2, Name: "curl", Cmdline: "curl google.com", Threads: 1},
-		2: {PID: 2, PPID: 1, Name: "bash", Cmdline: "bash", Threads: 1},
-		4: {PID: 4, PPID: 3, Name: "apache", Cmdline: "apache", Threads: 1},
-		1: {PID: 1, PPID: 0, Name: "init", Cmdline: "init", Threads: 1},
+		3: {PID: 3, PPID: 2, Name: "curl", Cmdline: "curl google.com", Threads: 1, FileDescriptors: 3},
+		2: {PID: 2, PPID: 1, Name: "bash", Cmdline: "bash", Threads: 1, FileDescriptors: 2},
+		4: {PID: 4, PPID: 3, Name: "apache", Cmdline: "apache", Threads: 1, FileDescriptors: 1},
+		1: {PID: 1, PPID: 0, Name: "init", Cmdline: "init", Threads: 1, FileDescriptors: 0},
 	}
 
 	have := map[int]process.Process{}

render/detailed/labels.go

@@ -42,6 +42,7 @@ var labels = map[string]string{
 	process.CPUUsage:             "CPU",
 	process.Cmdline:              "Command",
 	process.MemoryUsage:          "Memory",
+	process.FileDescriptors:      "Open Files",
 	process.PID:                  "PID",
 	process.PPID:                 "Parent PID",
 	process.Threads:              "# Threads",

render/detailed/metrics.go

@@ -13,13 +13,15 @@ import (
 const (
 	defaultFormat  = ""
 	filesizeFormat = "filesize"
+	integerFormat  = "integer"
 	percentFormat  = "percent"
 )
 
 var (
 	processNodeMetrics = []MetricRow{
 		{ID: process.CPUUsage, Format: percentFormat},
 		{ID: process.MemoryUsage, Format: filesizeFormat},
+		{ID: process.FileDescriptors, Format: integerFormat},
 	}
 	containerNodeMetrics = []MetricRow{
 		{ID: docker.CPUTotalUsage, Format: percentFormat},