[feature] Initial Prometheus metrics implementation (#2334)

* feat: Initial OTEL metrics

* docs: add metrics documentation

* fix: metrics endpoint conditional check

* feat: metrics endpoint basic auth

* fix: make metrics-auth-enabled default false

* fix: go fmt helpers.gen.go

* fix: add metric-related env vars to envparsing.sh

* fix: metrics docs

* fix: metrics related stuff in envparsing.sh

* fix: metrics docs

* chore: metrics docs wording

* fix: metrics stuff in envparsing?

* bump otel versions

---------

Co-authored-by: Tsuribori <user@acertaindebian>
Co-authored-by: Tsuribori <none@example.org>
Co-authored-by: tsmethurst <tobi.smethurst@protonmail.com>

1 files changed, 353 insertions, 0 deletions

diff --git a/vendor/github.com/prometheus/procfs/proc_snmp.go b/vendor/github.com/prometheus/procfs/proc_snmp.go
new file mode 100644
index 000000000..b9d2cf642
--- /dev/null
+++ b/vendor/github.com/prometheus/procfs/proc_snmp.go
@@ -0,0 +1,353 @@
+// Copyright 2022 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"
+	"fmt"
+	"io"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// ProcSnmp models the content of /proc/<pid>/net/snmp.
+type ProcSnmp struct {
+	// The process ID.
+	PID int
+	Ip
+	Icmp
+	IcmpMsg
+	Tcp
+	Udp
+	UdpLite
+}
+
+type Ip struct { // nolint:revive
+	Forwarding      *float64
+	DefaultTTL      *float64
+	InReceives      *float64
+	InHdrErrors     *float64
+	InAddrErrors    *float64
+	ForwDatagrams   *float64
+	InUnknownProtos *float64
+	InDiscards      *float64
+	InDelivers      *float64
+	OutRequests     *float64
+	OutDiscards     *float64
+	OutNoRoutes     *float64
+	ReasmTimeout    *float64
+	ReasmReqds      *float64
+	ReasmOKs        *float64
+	ReasmFails      *float64
+	FragOKs         *float64
+	FragFails       *float64
+	FragCreates     *float64
+}
+
+type Icmp struct { // nolint:revive
+	InMsgs           *float64
+	InErrors         *float64
+	InCsumErrors     *float64
+	InDestUnreachs   *float64
+	InTimeExcds      *float64
+	InParmProbs      *float64
+	InSrcQuenchs     *float64
+	InRedirects      *float64
+	InEchos          *float64
+	InEchoReps       *float64
+	InTimestamps     *float64
+	InTimestampReps  *float64
+	InAddrMasks      *float64
+	InAddrMaskReps   *float64
+	OutMsgs          *float64
+	OutErrors        *float64
+	OutDestUnreachs  *float64
+	OutTimeExcds     *float64
+	OutParmProbs     *float64
+	OutSrcQuenchs    *float64
+	OutRedirects     *float64
+	OutEchos         *float64
+	OutEchoReps      *float64
+	OutTimestamps    *float64
+	OutTimestampReps *float64
+	OutAddrMasks     *float64
+	OutAddrMaskReps  *float64
+}
+
+type IcmpMsg struct {
+	InType3  *float64
+	OutType3 *float64
+}
+
+type Tcp struct { // nolint:revive
+	RtoAlgorithm *float64
+	RtoMin       *float64
+	RtoMax       *float64
+	MaxConn      *float64
+	ActiveOpens  *float64
+	PassiveOpens *float64
+	AttemptFails *float64
+	EstabResets  *float64
+	CurrEstab    *float64
+	InSegs       *float64
+	OutSegs      *float64
+	RetransSegs  *float64
+	InErrs       *float64
+	OutRsts      *float64
+	InCsumErrors *float64
+}
+
+type Udp struct { // nolint:revive
+	InDatagrams  *float64
+	NoPorts      *float64
+	InErrors     *float64
+	OutDatagrams *float64
+	RcvbufErrors *float64
+	SndbufErrors *float64
+	InCsumErrors *float64
+	IgnoredMulti *float64
+}
+
+type UdpLite struct { // nolint:revive
+	InDatagrams  *float64
+	NoPorts      *float64
+	InErrors     *float64
+	OutDatagrams *float64
+	RcvbufErrors *float64
+	SndbufErrors *float64
+	InCsumErrors *float64
+	IgnoredMulti *float64
+}
+
+func (p Proc) Snmp() (ProcSnmp, error) {
+	filename := p.path("net/snmp")
+	data, err := util.ReadFileNoStat(filename)
+	if err != nil {
+		return ProcSnmp{PID: p.PID}, err
+	}
+	procSnmp, err := parseSnmp(bytes.NewReader(data), filename)
+	procSnmp.PID = p.PID
+	return procSnmp, err
+}
+
+// parseSnmp parses the metrics from proc/<pid>/net/snmp file
+// and returns a map contains those metrics (e.g. {"Ip": {"Forwarding": 2}}).
+func parseSnmp(r io.Reader, fileName string) (ProcSnmp, error) {
+	var (
+		scanner  = bufio.NewScanner(r)
+		procSnmp = ProcSnmp{}
+	)
+
+	for scanner.Scan() {
+		nameParts := strings.Split(scanner.Text(), " ")
+		scanner.Scan()
+		valueParts := strings.Split(scanner.Text(), " ")
+		// Remove trailing :.
+		protocol := strings.TrimSuffix(nameParts[0], ":")
+		if len(nameParts) != len(valueParts) {
+			return procSnmp, fmt.Errorf("%w: mismatch field count mismatch in %s: %s",
+				ErrFileParse, fileName, protocol)
+		}
+		for i := 1; i < len(nameParts); i++ {
+			value, err := strconv.ParseFloat(valueParts[i], 64)
+			if err != nil {
+				return procSnmp, err
+			}
+			key := nameParts[i]
+
+			switch protocol {
+			case "Ip":
+				switch key {
+				case "Forwarding":
+					procSnmp.Ip.Forwarding = &value
+				case "DefaultTTL":
+					procSnmp.Ip.DefaultTTL = &value
+				case "InReceives":
+					procSnmp.Ip.InReceives = &value
+				case "InHdrErrors":
+					procSnmp.Ip.InHdrErrors = &value
+				case "InAddrErrors":
+					procSnmp.Ip.InAddrErrors = &value
+				case "ForwDatagrams":
+					procSnmp.Ip.ForwDatagrams = &value
+				case "InUnknownProtos":
+					procSnmp.Ip.InUnknownProtos = &value
+				case "InDiscards":
+					procSnmp.Ip.InDiscards = &value
+				case "InDelivers":
+					procSnmp.Ip.InDelivers = &value
+				case "OutRequests":
+					procSnmp.Ip.OutRequests = &value
+				case "OutDiscards":
+					procSnmp.Ip.OutDiscards = &value
+				case "OutNoRoutes":
+					procSnmp.Ip.OutNoRoutes = &value
+				case "ReasmTimeout":
+					procSnmp.Ip.ReasmTimeout = &value
+				case "ReasmReqds":
+					procSnmp.Ip.ReasmReqds = &value
+				case "ReasmOKs":
+					procSnmp.Ip.ReasmOKs = &value
+				case "ReasmFails":
+					procSnmp.Ip.ReasmFails = &value
+				case "FragOKs":
+					procSnmp.Ip.FragOKs = &value
+				case "FragFails":
+					procSnmp.Ip.FragFails = &value
+				case "FragCreates":
+					procSnmp.Ip.FragCreates = &value
+				}
+			case "Icmp":
+				switch key {
+				case "InMsgs":
+					procSnmp.Icmp.InMsgs = &value
+				case "InErrors":
+					procSnmp.Icmp.InErrors = &value
+				case "InCsumErrors":
+					procSnmp.Icmp.InCsumErrors = &value
+				case "InDestUnreachs":
+					procSnmp.Icmp.InDestUnreachs = &value
+				case "InTimeExcds":
+					procSnmp.Icmp.InTimeExcds = &value
+				case "InParmProbs":
+					procSnmp.Icmp.InParmProbs = &value
+				case "InSrcQuenchs":
+					procSnmp.Icmp.InSrcQuenchs = &value
+				case "InRedirects":
+					procSnmp.Icmp.InRedirects = &value
+				case "InEchos":
+					procSnmp.Icmp.InEchos = &value
+				case "InEchoReps":
+					procSnmp.Icmp.InEchoReps = &value
+				case "InTimestamps":
+					procSnmp.Icmp.InTimestamps = &value
+				case "InTimestampReps":
+					procSnmp.Icmp.InTimestampReps = &value
+				case "InAddrMasks":
+					procSnmp.Icmp.InAddrMasks = &value
+				case "InAddrMaskReps":
+					procSnmp.Icmp.InAddrMaskReps = &value
+				case "OutMsgs":
+					procSnmp.Icmp.OutMsgs = &value
+				case "OutErrors":
+					procSnmp.Icmp.OutErrors = &value
+				case "OutDestUnreachs":
+					procSnmp.Icmp.OutDestUnreachs = &value
+				case "OutTimeExcds":
+					procSnmp.Icmp.OutTimeExcds = &value
+				case "OutParmProbs":
+					procSnmp.Icmp.OutParmProbs = &value
+				case "OutSrcQuenchs":
+					procSnmp.Icmp.OutSrcQuenchs = &value
+				case "OutRedirects":
+					procSnmp.Icmp.OutRedirects = &value
+				case "OutEchos":
+					procSnmp.Icmp.OutEchos = &value
+				case "OutEchoReps":
+					procSnmp.Icmp.OutEchoReps = &value
+				case "OutTimestamps":
+					procSnmp.Icmp.OutTimestamps = &value
+				case "OutTimestampReps":
+					procSnmp.Icmp.OutTimestampReps = &value
+				case "OutAddrMasks":
+					procSnmp.Icmp.OutAddrMasks = &value
+				case "OutAddrMaskReps":
+					procSnmp.Icmp.OutAddrMaskReps = &value
+				}
+			case "IcmpMsg":
+				switch key {
+				case "InType3":
+					procSnmp.IcmpMsg.InType3 = &value
+				case "OutType3":
+					procSnmp.IcmpMsg.OutType3 = &value
+				}
+			case "Tcp":
+				switch key {
+				case "RtoAlgorithm":
+					procSnmp.Tcp.RtoAlgorithm = &value
+				case "RtoMin":
+					procSnmp.Tcp.RtoMin = &value
+				case "RtoMax":
+					procSnmp.Tcp.RtoMax = &value
+				case "MaxConn":
+					procSnmp.Tcp.MaxConn = &value
+				case "ActiveOpens":
+					procSnmp.Tcp.ActiveOpens = &value
+				case "PassiveOpens":
+					procSnmp.Tcp.PassiveOpens = &value
+				case "AttemptFails":
+					procSnmp.Tcp.AttemptFails = &value
+				case "EstabResets":
+					procSnmp.Tcp.EstabResets = &value
+				case "CurrEstab":
+					procSnmp.Tcp.CurrEstab = &value
+				case "InSegs":
+					procSnmp.Tcp.InSegs = &value
+				case "OutSegs":
+					procSnmp.Tcp.OutSegs = &value
+				case "RetransSegs":
+					procSnmp.Tcp.RetransSegs = &value
+				case "InErrs":
+					procSnmp.Tcp.InErrs = &value
+				case "OutRsts":
+					procSnmp.Tcp.OutRsts = &value
+				case "InCsumErrors":
+					procSnmp.Tcp.InCsumErrors = &value
+				}
+			case "Udp":
+				switch key {
+				case "InDatagrams":
+					procSnmp.Udp.InDatagrams = &value
+				case "NoPorts":
+					procSnmp.Udp.NoPorts = &value
+				case "InErrors":
+					procSnmp.Udp.InErrors = &value
+				case "OutDatagrams":
+					procSnmp.Udp.OutDatagrams = &value
+				case "RcvbufErrors":
+					procSnmp.Udp.RcvbufErrors = &value
+				case "SndbufErrors":
+					procSnmp.Udp.SndbufErrors = &value
+				case "InCsumErrors":
+					procSnmp.Udp.InCsumErrors = &value
+				case "IgnoredMulti":
+					procSnmp.Udp.IgnoredMulti = &value
+				}
+			case "UdpLite":
+				switch key {
+				case "InDatagrams":
+					procSnmp.UdpLite.InDatagrams = &value
+				case "NoPorts":
+					procSnmp.UdpLite.NoPorts = &value
+				case "InErrors":
+					procSnmp.UdpLite.InErrors = &value
+				case "OutDatagrams":
+					procSnmp.UdpLite.OutDatagrams = &value
+				case "RcvbufErrors":
+					procSnmp.UdpLite.RcvbufErrors = &value
+				case "SndbufErrors":
+					procSnmp.UdpLite.SndbufErrors = &value
+				case "InCsumErrors":
+					procSnmp.UdpLite.InCsumErrors = &value
+				case "IgnoredMulti":
+					procSnmp.UdpLite.IgnoredMulti = &value
+				}
+			}
+		}
+	}
+	return procSnmp, scanner.Err()
+}