trigger

trigger

https://graphikdb.github.io/trigger/

a decision & trigger framework backed by Google's Common Expression Language used in graphikDB

• Full Text Search Expression Macros/Functions(startsWith, endsWith, contains)
• RegularExp Expression Macros/Functions(matches)
• Geographic Expression Macros/Functions(geoDistance)
• Cryptographic Expression Macros/Functions(encrypt, decrypt, sha1, sha256, sha3)
• JWT Expression Macros/Functions(parseClaims, parseHeader, parseSignature)
• Collection Expression Macros/Functions(in, map, filter, exists)
• String Manipulation Expression Macros/Functions(replace, join, titleCase, lowerCase, upperCase, trimSpace, trimPrefix, trimSuffix, render)
• URL Introspection Expression Macros/Functions(parseHost, parseScheme, parseQuery, parsePath)

Use Case:

Since this expression language requires just input data(map[string]interface) and an expression string, Go programs may use it to embed flexible logic that may be changed at runtime without having to recompile.

• Authorization Middleware/Policy Evaluation/Rule Engine

• Database or API "triggers" for mutating data before its commited

• Search Engine(filter something based on a decision)

Examples

restrict access based on domain

	decision, err := trigger.NewDecision("this.email.endsWith('acme.com')")
	if err != nil {
		fmt.Println(err.Error())
		return
	}
	err = decision.Eval(map[string]interface{}{
		"email": "bob@gmail.com",
	})
	fmt.Println(err == trigger.ErrDecisionDenied) 
    // Output: true 

create a trigger based on signup event that adds updated_at timestamp & hashes a password

	// create a trigger based on the new decision that hashes a password and creates an updated_at timestamp
	// this would in theory be applied to a newly created user after signup
	trigg, err := trigger.NewArrowTrigger(`
	this.event == 'signup' && has(this.email) =>
	{
		'updated_at': now(),
		'password': this.password.sha1()
	}
`)
	if err != nil {
		fmt.Println(err.Error())
		return
	}

	user := map[string]interface{}{
		"event": "signup",
		"name":  "bob",
		"email": "bob@acme.com",
		"password": "123456",
	}
	data, err := trigg.Trigger(user)
	if err != nil {
		fmt.Println(err.Error())
		return
	}
	fmt.Println(data["updated_at"].(int64) > 0, data["password"])
	// Output: true 7c4a8d09ca3762af61e59520943dc26494f8941b

CEL Macro Extensions

Additional details on the standard CEL spec/library may be found here