Mono repo -> Master (#22553)

Combines the following repositories into one:

https://github.com/mattermost/mattermost-server
https://github.com/mattermost/mattermost-webapp
https://github.com/mattermost/focalboard
https://github.com/mattermost/mattermost-plugin-playbooks

server/channels/app/users/service.go

@@ -0,0 +1,59 @@
+// Copyright (c) 2015-present Mattermost, Inc. All Rights Reserved.
+// See LICENSE.txt for license information.
+
+package users
+
+import (
+	"errors"
+
+	"github.com/mattermost/mattermost-server/v6/model"
+	"github.com/mattermost/mattermost-server/v6/server/channels/einterfaces"
+	"github.com/mattermost/mattermost-server/v6/server/channels/store"
+)
+
+type UserService struct {
+	store        store.UserStore
+	sessionStore store.SessionStore
+	oAuthStore   store.OAuthStore
+	metrics      einterfaces.MetricsInterface
+	cluster      einterfaces.ClusterInterface
+	config       func() *model.Config
+	license      func() *model.License
+}
+
+// ServiceConfig is used to initialize the UserService.
+type ServiceConfig struct {
+	// Mandatory fields
+	UserStore    store.UserStore
+	SessionStore store.SessionStore
+	OAuthStore   store.OAuthStore
+	ConfigFn     func() *model.Config
+	LicenseFn    func() *model.License
+	// Optional fields
+	Metrics einterfaces.MetricsInterface
+	Cluster einterfaces.ClusterInterface
+}
+
+func New(c ServiceConfig) (*UserService, error) {
+	if err := c.validate(); err != nil {
+		return nil, err
+	}
+
+	return &UserService{
+		store:        c.UserStore,
+		sessionStore: c.SessionStore,
+		oAuthStore:   c.OAuthStore,
+		config:       c.ConfigFn,
+		license:      c.LicenseFn,
+		metrics:      c.Metrics,
+		cluster:      c.Cluster,
+	}, nil
+}
+
+func (c *ServiceConfig) validate() error {
+	if c.ConfigFn == nil || c.UserStore == nil || c.SessionStore == nil || c.OAuthStore == nil || c.LicenseFn == nil {
+		return errors.New("required parameters are not provided")
+	}
+
+	return nil
+}