[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>

vendor/github.com/technologize/otel-go-contrib/otelginmetrics/option.go

@@ -0,0 +1,74 @@
+package otelginmetrics
+
+import (
+	"net/http"
+
+	"go.opentelemetry.io/otel/attribute"
+)
+
+// Option applies a configuration to the given config
+type Option interface {
+	apply(cfg *config)
+}
+
+type optionFunc func(cfg *config)
+
+func (fn optionFunc) apply(cfg *config) {
+	fn(cfg)
+}
+
+// WithAttributes sets a func using which what attributes to be recorded can be specified.
+// By default the DefaultAttributes is used
+func WithAttributes(attributes func(serverName, route string, request *http.Request) []attribute.KeyValue) Option {
+	return optionFunc(func(cfg *config) {
+		cfg.attributes = attributes
+	})
+}
+
+// WithRecordInFlight determines whether to record In Flight Requests or not
+// By default the recordInFlight is true
+func WithRecordInFlightDisabled() Option {
+	return optionFunc(func(cfg *config) {
+		cfg.recordInFlight = false
+	})
+}
+
+// WithRecordDuration determines whether to record Duration of Requests or not
+// By default the recordDuration is true
+func WithRecordDurationDisabled() Option {
+	return optionFunc(func(cfg *config) {
+		cfg.recordDuration = false
+	})
+}
+
+// WithRecordSize determines whether to record Size of Requests and Responses or not
+// By default the recordSize is true
+func WithRecordSizeDisabled() Option {
+	return optionFunc(func(cfg *config) {
+		cfg.recordSize = false
+	})
+}
+
+// WithGroupedStatus determines whether to group the response status codes or not. If true 2xx, 3xx will be stored
+// By default the groupedStatus is true
+func WithGroupedStatusDisabled() Option {
+	return optionFunc(func(cfg *config) {
+		cfg.groupedStatus = false
+	})
+}
+
+// WithRecorder sets a recorder for recording requests
+// By default the open telemetry recorder is used
+func WithRecorder(recorder Recorder) Option {
+	return optionFunc(func(cfg *config) {
+		cfg.recorder = recorder
+	})
+}
+
+// WithShouldRecordFunc sets a func using which whether a record should be recorded
+// By default the all api calls are recorded
+func WithShouldRecordFunc(shouldRecord func(serverName, route string, request *http.Request) bool) Option {
+	return optionFunc(func(cfg *config) {
+		cfg.shouldRecord = shouldRecord
+	})
+}