[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, 62 insertions, 0 deletions

diff --git a/vendor/github.com/prometheus/procfs/loadavg.go b/vendor/github.com/prometheus/procfs/loadavg.go
new file mode 100644
index 000000000..59465c5bb
--- /dev/null
+++ b/vendor/github.com/prometheus/procfs/loadavg.go
@@ -0,0 +1,62 @@
+// 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 (
+	"fmt"
+	"strconv"
+	"strings"
+
+	"github.com/prometheus/procfs/internal/util"
+)
+
+// LoadAvg represents an entry in /proc/loadavg.
+type LoadAvg struct {
+	Load1  float64
+	Load5  float64
+	Load15 float64
+}
+
+// LoadAvg returns loadavg from /proc.
+func (fs FS) LoadAvg() (*LoadAvg, error) {
+	path := fs.proc.Path("loadavg")
+
+	data, err := util.ReadFileNoStat(path)
+	if err != nil {
+		return nil, err
+	}
+	return parseLoad(data)
+}
+
+// Parse /proc loadavg and return 1m, 5m and 15m.
+func parseLoad(loadavgBytes []byte) (*LoadAvg, error) {
+	loads := make([]float64, 3)
+	parts := strings.Fields(string(loadavgBytes))
+	if len(parts) < 3 {
+		return nil, fmt.Errorf("%w: Malformed line %q", ErrFileParse, string(loadavgBytes))
+	}
+
+	var err error
+	for i, load := range parts[0:3] {
+		loads[i], err = strconv.ParseFloat(load, 64)
+		if err != nil {
+			return nil, fmt.Errorf("%s: Cannot parse load: %f: %w", ErrFileParse, loads[i], err)
+		}
+	}
+	return &LoadAvg{
+		Load1:  loads[0],
+		Load5:  loads[1],
+		Load15: loads[2],
+	}, nil
+}