Add package cluster :

- based on dragonboat lib (https://github.com/lni/dragonboat)
- add extended config with validate
- add backend managment to allow simple implementation for backend simple, cocurrent & disk
- has no backend implemented and must be a lib for a cluster mode of one backend

cluster/configExpert.go

@@ -0,0 +1,88 @@
+/***********************************************************************************************************************
+ *
+ *   MIT License
+ *
+ *   Copyright (c) 2021 Nicolas JUHEL
+ *
+ *   Permission is hereby granted, free of charge, to any person obtaining a copy
+ *   of this software and associated documentation files (the "Software"), to deal
+ *   in the Software without restriction, including without limitation the rights
+ *   to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ *   copies of the Software, and to permit persons to whom the Software is
+ *   furnished to do so, subject to the following conditions:
+ *
+ *   The above copyright notice and this permission notice shall be included in all
+ *   copies or substantial portions of the Software.
+ *
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ *   IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ *   FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ *   AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ *   LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ *   OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ *   SOFTWARE.
+ *
+ *
+ **********************************************************************************************************************/
+
+package cluster
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/go-playground/validator/v10"
+	dgbcfg "github.com/lni/dragonboat/v3/config"
+	liberr "github.com/nabbar/golib/errors"
+)
+
+type ConfigExpert struct {
+	// Engine is the cponfiguration for the execution engine.
+	Engine ConfigEngine `mapstructure:"engine" json:"engine" yaml:"engine" toml:"engine"`
+
+	// TestNodeHostID is the NodeHostID value to be used by the NodeHost instance.
+	// This field is expected to be used in tests only.
+	TestNodeHostID uint64 `mapstructure:"test_node_host_id" json:"test_node_host_id" yaml:"test_node_host_id" toml:"test_node_host_id"`
+
+	// TestGossipProbeInterval define the probe interval used by the gossip
+	// service in tests.
+	TestGossipProbeInterval time.Duration `mapstructure:"test_gossip_probe_interval" json:"test_gossip_probe_interval" yaml:"test_gossip_probe_interval" toml:"test_gossip_probe_interval"`
+}
+
+func (c ConfigExpert) GetDGBConfigExpert() dgbcfg.ExpertConfig {
+	d := dgbcfg.ExpertConfig{
+		Engine: c.Engine.GetDGBConfigEngine(),
+	}
+
+	if c.TestNodeHostID > 0 {
+		d.TestNodeHostID = c.TestNodeHostID
+	}
+
+	if c.TestGossipProbeInterval > 0 {
+		d.TestGossipProbeInterval = c.TestGossipProbeInterval
+	}
+
+	return d
+}
+
+func (c ConfigExpert) Validate() liberr.Error {
+	val := validator.New()
+	err := val.Struct(c)
+
+	if e, ok := err.(*validator.InvalidValidationError); ok {
+		return ErrorValidateExpert.ErrorParent(e)
+	}
+
+	out := ErrorValidateExpert.Error(nil)
+
+	for _, e := range err.(validator.ValidationErrors) {
+		//nolint goerr113
+		out.AddParent(fmt.Errorf("config field '%s' is not validated by constraint '%s'", e.Field(), e.ActualTag()))
+	}
+
+	if out.HasParent() {
+		return out
+	}
+
+	return nil
+}