[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, 202 insertions, 0 deletions

diff --git a/vendor/github.com/prometheus/procfs/proc_status.go b/vendor/github.com/prometheus/procfs/proc_status.go
new file mode 100644
index 000000000..c055d075d
--- /dev/null
+++ b/vendor/github.com/prometheus/procfs/proc_status.go
@@ -0,0 +1,202 @@
+// Copyright 2018 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 (
+	"bytes"
+	"sort"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// ProcStatus provides status information about the process,
+// read from /proc/[pid]/stat.
+type ProcStatus struct {
+	// The process ID.
+	PID int
+	// The process name.
+	Name string
+
+	// Thread group ID.
+	TGID int
+
+	// Peak virtual memory size.
+	VmPeak uint64 // nolint:revive
+	// Virtual memory size.
+	VmSize uint64 // nolint:revive
+	// Locked memory size.
+	VmLck uint64 // nolint:revive
+	// Pinned memory size.
+	VmPin uint64 // nolint:revive
+	// Peak resident set size.
+	VmHWM uint64 // nolint:revive
+	// Resident set size (sum of RssAnnon RssFile and RssShmem).
+	VmRSS uint64 // nolint:revive
+	// Size of resident anonymous memory.
+	RssAnon uint64 // nolint:revive
+	// Size of resident file mappings.
+	RssFile uint64 // nolint:revive
+	// Size of resident shared memory.
+	RssShmem uint64 // nolint:revive
+	// Size of data segments.
+	VmData uint64 // nolint:revive
+	// Size of stack segments.
+	VmStk uint64 // nolint:revive
+	// Size of text segments.
+	VmExe uint64 // nolint:revive
+	// Shared library code size.
+	VmLib uint64 // nolint:revive
+	// Page table entries size.
+	VmPTE uint64 // nolint:revive
+	// Size of second-level page tables.
+	VmPMD uint64 // nolint:revive
+	// Swapped-out virtual memory size by anonymous private.
+	VmSwap uint64 // nolint:revive
+	// Size of hugetlb memory portions
+	HugetlbPages uint64
+
+	// Number of voluntary context switches.
+	VoluntaryCtxtSwitches uint64
+	// Number of involuntary context switches.
+	NonVoluntaryCtxtSwitches uint64
+
+	// UIDs of the process (Real, effective, saved set, and filesystem UIDs)
+	UIDs [4]string
+	// GIDs of the process (Real, effective, saved set, and filesystem GIDs)
+	GIDs [4]string
+
+	// CpusAllowedList: List of cpu cores processes are allowed to run on.
+	CpusAllowedList []uint64
+}
+
+// NewStatus returns the current status information of the process.
+func (p Proc) NewStatus() (ProcStatus, error) {
+	data, err := util.ReadFileNoStat(p.path("status"))
+	if err != nil {
+		return ProcStatus{}, err
+	}
+
+	s := ProcStatus{PID: p.PID}
+
+	lines := strings.Split(string(data), "\n")
+	for _, line := range lines {
+		if !bytes.Contains([]byte(line), []byte(":")) {
+			continue
+		}
+
+		kv := strings.SplitN(line, ":", 2)
+
+		// removes spaces
+		k := strings.TrimSpace(kv[0])
+		v := strings.TrimSpace(kv[1])
+		// removes "kB"
+		v = strings.TrimSuffix(v, " kB")
+
+		// value to int when possible
+		// we can skip error check here, 'cause vKBytes is not used when value is a string
+		vKBytes, _ := strconv.ParseUint(v, 10, 64)
+		// convert kB to B
+		vBytes := vKBytes * 1024
+
+		s.fillStatus(k, v, vKBytes, vBytes)
+	}
+
+	return s, nil
+}
+
+func (s *ProcStatus) fillStatus(k string, vString string, vUint uint64, vUintBytes uint64) {
+	switch k {
+	case "Tgid":
+		s.TGID = int(vUint)
+	case "Name":
+		s.Name = vString
+	case "Uid":
+		copy(s.UIDs[:], strings.Split(vString, "\t"))
+	case "Gid":
+		copy(s.GIDs[:], strings.Split(vString, "\t"))
+	case "VmPeak":
+		s.VmPeak = vUintBytes
+	case "VmSize":
+		s.VmSize = vUintBytes
+	case "VmLck":
+		s.VmLck = vUintBytes
+	case "VmPin":
+		s.VmPin = vUintBytes
+	case "VmHWM":
+		s.VmHWM = vUintBytes
+	case "VmRSS":
+		s.VmRSS = vUintBytes
+	case "RssAnon":
+		s.RssAnon = vUintBytes
+	case "RssFile":
+		s.RssFile = vUintBytes
+	case "RssShmem":
+		s.RssShmem = vUintBytes
+	case "VmData":
+		s.VmData = vUintBytes
+	case "VmStk":
+		s.VmStk = vUintBytes
+	case "VmExe":
+		s.VmExe = vUintBytes
+	case "VmLib":
+		s.VmLib = vUintBytes
+	case "VmPTE":
+		s.VmPTE = vUintBytes
+	case "VmPMD":
+		s.VmPMD = vUintBytes
+	case "VmSwap":
+		s.VmSwap = vUintBytes
+	case "HugetlbPages":
+		s.HugetlbPages = vUintBytes
+	case "voluntary_ctxt_switches":
+		s.VoluntaryCtxtSwitches = vUint
+	case "nonvoluntary_ctxt_switches":
+		s.NonVoluntaryCtxtSwitches = vUint
+	case "Cpus_allowed_list":
+		s.CpusAllowedList = calcCpusAllowedList(vString)
+	}
+
+}
+
+// TotalCtxtSwitches returns the total context switch.
+func (s ProcStatus) TotalCtxtSwitches() uint64 {
+	return s.VoluntaryCtxtSwitches + s.NonVoluntaryCtxtSwitches
+}
+
+func calcCpusAllowedList(cpuString string) []uint64 {
+	s := strings.Split(cpuString, ",")
+
+	var g []uint64
+
+	for _, cpu := range s {
+		// parse cpu ranges, example: 1-3=[1,2,3]
+		if l := strings.Split(strings.TrimSpace(cpu), "-"); len(l) > 1 {
+			startCPU, _ := strconv.ParseUint(l[0], 10, 64)
+			endCPU, _ := strconv.ParseUint(l[1], 10, 64)
+
+			for i := startCPU; i <= endCPU; i++ {
+				g = append(g, i)
+			}
+		} else if len(l) == 1 {
+			cpu, _ := strconv.ParseUint(l[0], 10, 64)
+			g = append(g, cpu)
+		}
+
+	}
+
+	sort.Slice(g, func(i, j int) bool { return g[i] < g[j] })
+	return g
+}