Add NetStat to parse /proc/net/stat/... (#316)

* Add NetStat to parse /proc/net/stat/...

Signed-off-by: Aleksei Zakharov <[email protected]>

Author: AlexZzz

fixtures.ttar

@@ -2209,6 +2209,23 @@ Lines: 1
 00015c73 00020e76 F0000769 00000000
 Mode: 644
 # ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Directory: fixtures/proc/net/stat
+Mode: 755
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Path: fixtures/proc/net/stat/arp_cache
+Lines: 3
+entries  allocs destroys hash_grows  lookups hits  res_failed  rcv_probes_mcast rcv_probes_ucast  periodic_gc_runs forced_gc_runs unresolved_discards table_fulls
+00000014  00000001 00000002 00000003  00000004 00000005  00000006  00000007 00000008  00000009 0000000a 0000000b 0000000c
+00000014  0000000d 0000000e 0000000f  00000010 00000011  00000012  00000013 00000014  00000015 00000016 00000017 00000018
+Mode: 644
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+Path: fixtures/proc/net/stat/ndisc_cache
+Lines: 3
+entries  allocs destroys hash_grows  lookups hits  res_failed  rcv_probes_mcast rcv_probes_ucast  periodic_gc_runs forced_gc_runs unresolved_discards table_fulls
+00000024  000000f0 000000f1 000000f2  000000f3 000000f4  000000f5  000000f6 000000f7  000000f8 000000f9 000000fa 000000fb
+00000024  000000fc 000000fd 000000fe  000000ff 00000100  00000101  00000102 00000103  00000104 00000105 00000106 00000107
+Mode: 644
+# ttar - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 Path: fixtures/proc/net/tcp
 Lines: 4
   sl  local_address rem_address   st tx_queue rx_queue tr tm->when retrnsmt   uid  timeout inode

netstat.go

@@ -0,0 +1,68 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"bufio"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+)
+
+// NetStat contains statistics for all the counters from one file
+type NetStat struct {
+	Filename string
+	Stats    map[string][]uint64
+}
+
+// NetStat retrieves stats from /proc/net/stat/
+func (fs FS) NetStat() ([]NetStat, error) {
+	statFiles, err := filepath.Glob(fs.proc.Path("net/stat/*"))
+	if err != nil {
+		return nil, err
+	}
+
+	var netStatsTotal []NetStat
+
+	for _, filePath := range statFiles {
+		file, err := os.Open(filePath)
+		if err != nil {
+			return nil, err
+		}
+
+		netStatFile := NetStat{
+			Filename: filepath.Base(filePath),
+			Stats:    make(map[string][]uint64),
+		}
+		scanner := bufio.NewScanner(file)
+		scanner.Scan()
+		// First string is always a header for stats
+		var headers []string
+		headers = append(headers, strings.Fields(scanner.Text())...)
+
+		// Other strings represent per-CPU counters
+		for scanner.Scan() {
+			for num, counter := range strings.Fields(scanner.Text()) {
+				value, err := strconv.ParseUint(counter, 16, 32)
+				if err != nil {
+					return nil, err
+				}
+				netStatFile.Stats[headers[num]] = append(netStatFile.Stats[headers[num]], value)
+			}
+		}
+		netStatsTotal = append(netStatsTotal, netStatFile)
+	}
+	return netStatsTotal, nil
+}

netstat_test.go

@@ -0,0 +1,114 @@
+// Copyright 2020 The Prometheus Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package procfs
+
+import (
+	"testing"
+)
+
+func TestNetStat(t *testing.T) {
+	const (
+		filesCount             = 2
+		CPUsCount              = 2
+		arpCacheMetricsCount   = 13
+		ndiscCacheMetricsCount = 13
+	)
+
+	fs, err := NewFS(procTestFixtures)
+	if err != nil {
+		t.Fatalf("failed to open procfs: %v", err)
+	}
+
+	netStats, err := fs.NetStat()
+	if err != nil {
+		t.Fatalf("NetStat() error: %s", err)
+	}
+
+	if len(netStats) != filesCount {
+		t.Fatalf("unexpected number of files parsed %d, expected %d", len(netStats), filesCount)
+	}
+
+	expectedStats := [2]NetStat{
+		{
+			Filename: "arp_cache",
+			Stats:    make(map[string][]uint64),
+		},
+		{
+			Filename: "ndisc_cache",
+			Stats:    make(map[string][]uint64),
+		},
+	}
+
+	for _, expected := range expectedStats {
+		if expected.Filename == "arp_cache" {
+			expected.Stats["entries"] = []uint64{20, 20}
+			expected.Stats["allocs"] = []uint64{1, 13}
+			expected.Stats["destroys"] = []uint64{2, 14}
+			expected.Stats["hash_grows"] = []uint64{3, 15}
+			expected.Stats["lookups"] = []uint64{4, 16}
+			expected.Stats["hits"] = []uint64{5, 17}
+			expected.Stats["res_failed"] = []uint64{6, 18}
+			expected.Stats["rcv_probes_mcast"] = []uint64{7, 19}
+			expected.Stats["rcv_probes_ucast"] = []uint64{8, 20}
+			expected.Stats["periodic_gc_runs"] = []uint64{9, 21}
+			expected.Stats["forced_gc_runs"] = []uint64{10, 22}
+			expected.Stats["unresolved_discards"] = []uint64{11, 23}
+			expected.Stats["table_fulls"] = []uint64{12, 24}
+		}
+		if expected.Filename == "ndisc_cache" {
+			expected.Stats["entries"] = []uint64{36, 36}
+			expected.Stats["allocs"] = []uint64{240, 252}
+			expected.Stats["destroys"] = []uint64{241, 253}
+			expected.Stats["hash_grows"] = []uint64{242, 254}
+			expected.Stats["lookups"] = []uint64{243, 255}
+			expected.Stats["hits"] = []uint64{244, 256}
+			expected.Stats["res_failed"] = []uint64{245, 257}
+			expected.Stats["rcv_probes_mcast"] = []uint64{246, 258}
+			expected.Stats["rcv_probes_ucast"] = []uint64{247, 259}
+			expected.Stats["periodic_gc_runs"] = []uint64{248, 260}
+			expected.Stats["forced_gc_runs"] = []uint64{249, 261}
+			expected.Stats["unresolved_discards"] = []uint64{250, 262}
+			expected.Stats["table_fulls"] = []uint64{251, 263}
+		}
+	}
+
+	for _, netStatFile := range netStats {
+		if netStatFile.Filename == "arp_cache" && len(netStatFile.Stats) != arpCacheMetricsCount {
+			t.Fatalf("unexpected arp_cache metrics count %d, expected %d", len(netStatFile.Stats), arpCacheMetricsCount)
+		}
+		if netStatFile.Filename == "ndisc_cache" && len(netStatFile.Stats) != ndiscCacheMetricsCount {
+			t.Fatalf("unexpected ndisc_cache metrics count %d, expected %d", len(netStatFile.Stats), ndiscCacheMetricsCount)
+		}
+		for _, expected := range expectedStats {
+			for header, stats := range netStatFile.Stats {
+				if header == "" {
+					t.Fatalf("Found empty metric name")
+				}
+				if len(stats) != CPUsCount {
+					t.Fatalf("NetStat() parsed %d lines with metrics, expected %d", len(stats), CPUsCount)
+				}
+				if netStatFile.Filename == expected.Filename {
+					if expected.Stats[header] == nil {
+						t.Fatalf("unexpected metric header: %s", header)
+					}
+					for cpu, value := range netStatFile.Stats[header] {
+						if expected.Stats[header][cpu] != value {
+							t.Fatalf("unexpected value for %s for cpu %d in %s: %d, expected %d", header, cpu, netStatFile.Filename, value, expected.Stats[header][cpu])
+						}
+					}
+				}
+			}
+		}
+	}
+}