vendor: add github.com/prometheus/client_golang/prometheus

Signed-off-by: Gary Kim <gary@garykim.dev>

vendor/github.com/prometheus/procfs/net_sockstat.go

@@ -0,0 +1,163 @@
+// Copyright 2019 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"
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// A NetSockstat contains the output of /proc/net/sockstat{,6} for IPv4 or IPv6,
+// respectively.
+type NetSockstat struct {
+	// Used is non-nil for IPv4 sockstat results, but nil for IPv6.
+	Used      *int
+	Protocols []NetSockstatProtocol
+}
+
+// A NetSockstatProtocol contains statistics about a given socket protocol.
+// Pointer fields indicate that the value may or may not be present on any
+// given protocol.
+type NetSockstatProtocol struct {
+	Protocol string
+	InUse    int
+	Orphan   *int
+	TW       *int
+	Alloc    *int
+	Mem      *int
+	Memory   *int
+}
+
+// NetSockstat retrieves IPv4 socket statistics.
+func (fs FS) NetSockstat() (*NetSockstat, error) {
+	return readSockstat(fs.proc.Path("net", "sockstat"))
+}
+
+// NetSockstat6 retrieves IPv6 socket statistics.
+//
+// If IPv6 is disabled on this kernel, the returned error can be checked with
+// os.IsNotExist.
+func (fs FS) NetSockstat6() (*NetSockstat, error) {
+	return readSockstat(fs.proc.Path("net", "sockstat6"))
+}
+
+// readSockstat opens and parses a NetSockstat from the input file.
+func readSockstat(name string) (*NetSockstat, error) {
+	// This file is small and can be read with one syscall.
+	b, err := util.ReadFileNoStat(name)
+	if err != nil {
+		// Do not wrap this error so the caller can detect os.IsNotExist and
+		// similar conditions.
+		return nil, err
+	}
+
+	stat, err := parseSockstat(bytes.NewReader(b))
+	if err != nil {
+		return nil, fmt.Errorf("failed to read sockstats from %q: %v", name, err)
+	}
+
+	return stat, nil
+}
+
+// parseSockstat reads the contents of a sockstat file and parses a NetSockstat.
+func parseSockstat(r io.Reader) (*NetSockstat, error) {
+	var stat NetSockstat
+	s := bufio.NewScanner(r)
+	for s.Scan() {
+		// Expect a minimum of a protocol and one key/value pair.
+		fields := strings.Split(s.Text(), " ")
+		if len(fields) < 3 {
+			return nil, fmt.Errorf("malformed sockstat line: %q", s.Text())
+		}
+
+		// The remaining fields are key/value pairs.
+		kvs, err := parseSockstatKVs(fields[1:])
+		if err != nil {
+			return nil, fmt.Errorf("error parsing sockstat key/value pairs from %q: %v", s.Text(), err)
+		}
+
+		// The first field is the protocol. We must trim its colon suffix.
+		proto := strings.TrimSuffix(fields[0], ":")
+		switch proto {
+		case "sockets":
+			// Special case: IPv4 has a sockets "used" key/value pair that we
+			// embed at the top level of the structure.
+			used := kvs["used"]
+			stat.Used = &used
+		default:
+			// Parse all other lines as individual protocols.
+			nsp := parseSockstatProtocol(kvs)
+			nsp.Protocol = proto
+			stat.Protocols = append(stat.Protocols, nsp)
+		}
+	}
+
+	if err := s.Err(); err != nil {
+		return nil, err
+	}
+
+	return &stat, nil
+}
+
+// parseSockstatKVs parses a string slice into a map of key/value pairs.
+func parseSockstatKVs(kvs []string) (map[string]int, error) {
+	if len(kvs)%2 != 0 {
+		return nil, errors.New("odd number of fields in key/value pairs")
+	}
+
+	// Iterate two values at a time to gather key/value pairs.
+	out := make(map[string]int, len(kvs)/2)
+	for i := 0; i < len(kvs); i += 2 {
+		vp := util.NewValueParser(kvs[i+1])
+		out[kvs[i]] = vp.Int()
+
+		if err := vp.Err(); err != nil {
+			return nil, err
+		}
+	}
+
+	return out, nil
+}
+
+// parseSockstatProtocol parses a NetSockstatProtocol from the input kvs map.
+func parseSockstatProtocol(kvs map[string]int) NetSockstatProtocol {
+	var nsp NetSockstatProtocol
+	for k, v := range kvs {
+		// Capture the range variable to ensure we get unique pointers for
+		// each of the optional fields.
+		v := v
+		switch k {
+		case "inuse":
+			nsp.InUse = v
+		case "orphan":
+			nsp.Orphan = &v
+		case "tw":
+			nsp.TW = &v
+		case "alloc":
+			nsp.Alloc = &v
+		case "mem":
+			nsp.Mem = &v
+		case "memory":
+			nsp.Memory = &v
+		}
+	}
+
+	return nsp
+}