[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/go.opentelemetry.io/otel/semconv/v1.7.0/http.go

@@ -0,0 +1,114 @@
+// Copyright The OpenTelemetry 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 semconv // import "go.opentelemetry.io/otel/semconv/v1.7.0"
+
+import (
+	"net/http"
+
+	"go.opentelemetry.io/otel/attribute"
+	"go.opentelemetry.io/otel/codes"
+	"go.opentelemetry.io/otel/semconv/internal"
+	"go.opentelemetry.io/otel/trace"
+)
+
+// HTTP scheme attributes.
+var (
+	HTTPSchemeHTTP  = HTTPSchemeKey.String("http")
+	HTTPSchemeHTTPS = HTTPSchemeKey.String("https")
+)
+
+var sc = &internal.SemanticConventions{
+	EnduserIDKey:                EnduserIDKey,
+	HTTPClientIPKey:             HTTPClientIPKey,
+	HTTPFlavorKey:               HTTPFlavorKey,
+	HTTPHostKey:                 HTTPHostKey,
+	HTTPMethodKey:               HTTPMethodKey,
+	HTTPRequestContentLengthKey: HTTPRequestContentLengthKey,
+	HTTPRouteKey:                HTTPRouteKey,
+	HTTPSchemeHTTP:              HTTPSchemeHTTP,
+	HTTPSchemeHTTPS:             HTTPSchemeHTTPS,
+	HTTPServerNameKey:           HTTPServerNameKey,
+	HTTPStatusCodeKey:           HTTPStatusCodeKey,
+	HTTPTargetKey:               HTTPTargetKey,
+	HTTPURLKey:                  HTTPURLKey,
+	HTTPUserAgentKey:            HTTPUserAgentKey,
+	NetHostIPKey:                NetHostIPKey,
+	NetHostNameKey:              NetHostNameKey,
+	NetHostPortKey:              NetHostPortKey,
+	NetPeerIPKey:                NetPeerIPKey,
+	NetPeerNameKey:              NetPeerNameKey,
+	NetPeerPortKey:              NetPeerPortKey,
+	NetTransportIP:              NetTransportIP,
+	NetTransportOther:           NetTransportOther,
+	NetTransportTCP:             NetTransportTCP,
+	NetTransportUDP:             NetTransportUDP,
+	NetTransportUnix:            NetTransportUnix,
+}
+
+// NetAttributesFromHTTPRequest generates attributes of the net
+// namespace as specified by the OpenTelemetry specification for a
+// span.  The network parameter is a string that net.Dial function
+// from standard library can understand.
+func NetAttributesFromHTTPRequest(network string, request *http.Request) []attribute.KeyValue {
+	return sc.NetAttributesFromHTTPRequest(network, request)
+}
+
+// EndUserAttributesFromHTTPRequest generates attributes of the
+// enduser namespace as specified by the OpenTelemetry specification
+// for a span.
+func EndUserAttributesFromHTTPRequest(request *http.Request) []attribute.KeyValue {
+	return sc.EndUserAttributesFromHTTPRequest(request)
+}
+
+// HTTPClientAttributesFromHTTPRequest generates attributes of the
+// http namespace as specified by the OpenTelemetry specification for
+// a span on the client side.
+func HTTPClientAttributesFromHTTPRequest(request *http.Request) []attribute.KeyValue {
+	return sc.HTTPClientAttributesFromHTTPRequest(request)
+}
+
+// HTTPServerMetricAttributesFromHTTPRequest generates low-cardinality attributes
+// to be used with server-side HTTP metrics.
+func HTTPServerMetricAttributesFromHTTPRequest(serverName string, request *http.Request) []attribute.KeyValue {
+	return sc.HTTPServerMetricAttributesFromHTTPRequest(serverName, request)
+}
+
+// HTTPServerAttributesFromHTTPRequest generates attributes of the
+// http namespace as specified by the OpenTelemetry specification for
+// a span on the server side. Currently, only basic authentication is
+// supported.
+func HTTPServerAttributesFromHTTPRequest(serverName, route string, request *http.Request) []attribute.KeyValue {
+	return sc.HTTPServerAttributesFromHTTPRequest(serverName, route, request)
+}
+
+// HTTPAttributesFromHTTPStatusCode generates attributes of the http
+// namespace as specified by the OpenTelemetry specification for a
+// span.
+func HTTPAttributesFromHTTPStatusCode(code int) []attribute.KeyValue {
+	return sc.HTTPAttributesFromHTTPStatusCode(code)
+}
+
+// SpanStatusFromHTTPStatusCode generates a status code and a message
+// as specified by the OpenTelemetry specification for a span.
+func SpanStatusFromHTTPStatusCode(code int) (codes.Code, string) {
+	return internal.SpanStatusFromHTTPStatusCode(code)
+}
+
+// SpanStatusFromHTTPStatusCodeAndSpanKind generates a status code and a message
+// as specified by the OpenTelemetry specification for a span.
+// Exclude 4xx for SERVER to set the appropriate status.
+func SpanStatusFromHTTPStatusCodeAndSpanKind(code int, spanKind trace.SpanKind) (codes.Code, string) {
+	return internal.SpanStatusFromHTTPStatusCodeAndSpanKind(code, spanKind)
+}