MM-21898: Part 2. Add opentracing (#13904)

* initial implementation of opentracing

* app layer

* Revert Makefile

* .

* cleanup

* .

* .

* .

* .

* .

* .

* .

* .

* .

* .

* .

* [ci]

* autogenerate interface

* .

* missed vendor files

* updated interfaces

* updated store layers

* lint fixes

* .

* finishing layer generators and nested spans

* added errors and b3 support

* code review

* .

* .

* fixed build error due to misplased flag.Parse()

* code review addressed

store/layer_generators/timer_layer.go.tmpl

@@ -0,0 +1,78 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+// Code generated by "make store-layers"
+// DO NOT EDIT
+
+package store
+
+import (
+	"context"
+	timemodule "time"
+	
+    "github.com/mattermost/mattermost-server/v5/einterfaces"
+	"github.com/mattermost/mattermost-server/v5/model"
+)
+
+type {{.Name}} struct {
+	Store
+	Metrics einterfaces.MetricsInterface
+{{range $index, $element := .SubStores}}	{{$index}}Store {{$index}}Store
+{{end}}
+}
+
+{{range $index, $element := .SubStores}}func (s *{{$.Name}}) {{$index}}() {{$index}}Store {
+	return s.{{$index}}Store
+}
+
+{{end}}
+
+{{range $index, $element := .SubStores}}type {{$.Name}}{{$index}}Store struct {
+	{{$index}}Store
+	Root *{{$.Name}}
+}
+
+{{end}}
+
+{{range $substoreName, $substore := .SubStores}}
+{{range $index, $element := $substore.Methods}}
+func (s *{{$.Name}}{{$substoreName}}Store) {{$index}}({{$element.Params | joinParamsWithType}}) {{$element.Results | joinResultsForSignature}} {
+	start := timemodule.Now()
+	{{if $element.Results | len | eq 0}}
+	s.{{$substoreName}}Store.{{$index}}({{$element.Params | joinParams}})
+	{{else}}
+	{{$element.Results | genResultsVars}} := s.{{$substoreName}}Store.{{$index}}({{$element.Params | joinParams}})
+	{{end}}
+	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
+	if s.Root.Metrics != nil {
+		success := "false"
+		if {{$element.Results | errorToBoolean}} {
+			success = "true"
+		}
+		s.Root.Metrics.ObserveStoreMethodDuration("{{$substoreName}}Store.{{$index}}", success, elapsed)
+	{{ with ($element.Results | genResultsVars) -}}
+	}
+	return {{ . }}
+	{{- else -}}
+	}
+	{{- end }}
+}
+{{end}}
+{{end}}
+
+{{range $index, $element := .Methods}}
+func (s *{{$.Name}}) {{$index}}({{$element.Params | joinParamsWithType}}) {{$element.Results | joinResultsForSignature}} {
+	{{if $element.Results | len | eq 0}}s.Store.{{$index}}({{$element.Params | joinParams}})
+	{{else}}return s.Store.{{$index}}({{$element.Params | joinParams}})
+	{{end}}}
+{{end}}
+
+func New{{.Name}}(childStore Store, metrics einterfaces.MetricsInterface) *{{.Name}} {
+	newStore := {{.Name}}{
+		Store: childStore,
+		Metrics: metrics,
+	}
+	{{range $substoreName, $substore := .SubStores}}
+	newStore.{{$substoreName}}Store = &{{$.Name}}{{$substoreName}}Store{{"{"}}{{$substoreName}}Store: childStore.{{$substoreName}}(), Root: &newStore}{{end}}
+	return &newStore
+}