Golang implements rule engine

With the continuous development of artificial intelligence technology, various rule engines are increasingly widely used in various fields, such as finance, medical care, industry, etc. The rules engine can abstract business logic and rules and realize automated execution of rules, thereby improving efficiency and accuracy. This article will introduce how to use golang to implement a rules engine.

1. Basic principles of rule engine

Before introducing the implementation principle of rule engine, we must first understand the basic concepts and components of rule engine.

The rule engine is composed of three parts: conditions, actions and events. Conditions refer to the prerequisites for rule detection, actions refer to actions that need to be executed after the rules are executed, and events refer to the rules engine that will trigger execution when a specific event occurs.

Specifically, the rule engine includes the following components:

1. Rule template: The rule template is used to describe the structure and components of the rule. It contains elements such as conditions, actions, and events. .
2. Rule engine: The rule engine is a software system that is used to parse rule templates and perform tasks such as rule detection and action execution.
3. Rule base: The rule base is an important part of the rule engine. It contains all rule sets and can be classified according to different types.

2. Basic steps for implementing rule engine in golang

1. Define rule template

In golang, you can use struct structure to define Rule template. Specifically, the rule template contains three parts: conditions, actions, and events.

The type is defined as follows:

//条件
type Condition struct {
    Field string
    Operator string
    Value interface{}
}
//动作
type Action struct {
    Field string
    Operator string
    Value interface{}
}
//事件
type Event struct {
    Name string
    Conditions []Condition
    Actions []Action
}

2. Parsing rule template

The purpose of parsing rule template is to convert the rule template into a data structure that can be executed by the computer. Such as map, slice, etc. Specifically, you can use the json.Unmarshal() function in golang to parse the rule template in json format into a rule template structure.

The sample code is as follows:

type Rule struct {
    Events []Event `json:"events"`
}

func ParseRule(ruleJson string) (Rule, error) {
    var rule Rule
    err := json.Unmarshal([]byte(ruleJson), &rule)
    if err != nil {
        return Rule{}, err
    }
    return rule, nil
}

3. Establishing a rule base

The purpose of establishing a rule base is to store all rules and perform classified management. The rule base can be implemented using map in golang, where key is the rule type and value is the rule set.

The sample code is as follows:

type RuleSet map[string][]Rule

func (ruleSet RuleSet) AddRule(rule Rule, ruleType string) {
    if _, ok := ruleSet[ruleType]; !ok {
        ruleSet[ruleType] = make([]Rule, 0)
    }
    ruleSet[ruleType] = append(ruleSet[ruleType], rule)
}

4. Implementing rule detection

The purpose of implementing rule detection is to determine whether an input meets the conditions of the rule. In golang, you can use the ValueOf() function in the reflect package to obtain the type and value of the input data, and then perform conditional judgment.

The sample code is as follows:

func Check(event Event, data interface{}) bool {
    v := reflect.ValueOf(data)
    for _, condition := range event.Conditions {
        fieldValue := v.FieldByName(condition.Field).Interface()
        conditionValue := condition.Value
        operator := condition.Operator
        switch operator {
        case "==":
            if fieldValue != conditionValue {
                return false
            }
        case ">":
            if fieldValue.(float64) <= conditionValue.(float64) {
                return false
            }
        case "<":
            if fieldValue.(float64) >= conditionValue.(float64) {
                return false
            }
        //其它操作符实现相应逻辑
        }
    }
    return true
}

5. Achieving action execution

The purpose of implementing action execution is to execute actions according to rules, such as sending emails, text messages, and modifications Database etc. In golang, you can use the database/sql package to operate the database and the net/smtp package to send emails.

The sample code is as follows:

func ExecuteAction(action Action, data interface{}) {
    v := reflect.ValueOf(data)
    fieldValue := v.FieldByName(action.Field)
    switch action.Operator {
    case "=":
        fieldValue.Set(reflect.ValueOf(action.Value))
    //其它操作符实现相应逻辑
    }
}

func ExecuteActions(actions []Action, data interface{}) {
    for _, action := range actions {
        ExecuteAction(action, data)
    }
}

6. Complete the rule engine

The purpose of the completed rule engine is to integrate all components to achieve automated rule detection and action execution. In golang, you can define a RuleEngine structure, which contains the rule base, input data, and rule execution functions.

The sample code is as follows:

type RuleEngine struct {
    RuleSet RuleSet
    Data interface{}
}

func NewRuleEngine(ruleSet RuleSet, data interface{}) RuleEngine {
    return RuleEngine{ruleSet, data}
}

func (engine RuleEngine) Run() {
    for ruleType, rules := range engine.RuleSet {
        for _, rule := range rules {
            for _, event := range rule.Events {
                if event.Name != "input" {
                    continue
                }
                if !Check(event, engine.Data) {
                    continue
                }
                ExecuteActions(event.Actions, engine.Data)
            }
        }
    }
}

3. Summary

This article introduces how to use golang to implement the rule engine, including rule template definition, rule base establishment, rule detection and action execution wait. Rule engines have a wide range of applications, which can improve business efficiency and accuracy, and can also provide strong support for the development of artificial intelligence technology.

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