trigger

README

trigger

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

	decision, err := trigger.NewDecision("this.email.endsWith('acme.com')")
	if err != nil {
		fmt.Println(err.Error())
		return
	}
	trigg, err := trigger.NewTrigger(decision, `
	{
		'admin': true,
		'updated_at': now(),
		'email_hash': sha1(this.email)
	}
`)
	if err != nil {
		fmt.Println(err.Error())
		return
	}
	person := map[string]interface{}{
		"name":  "bob",
		"email": "bob@acme.com",
	}
	data, err := trigg.Trigger(person)
	if err != nil {
		fmt.Println(err.Error())
		return
	}
	fmt.Println(data["admin"], data["updated_at"].(int64) > 0, data["email_hash"])
	// Output: true true 6fd706dd2d151c2bf79218a2acd764a7d3eed7e3

CEL Macro Extensions

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

function	notation	description
now	now() int64	current timestamp in unix secods
uuid	uuid() string	random uuidv4 string
sha1	sha1(string) string	sha1 hash of the input string
sha256	sha256(string) string	sha256 hash of the input string
sha3	sha3(string) string	sha3 hash of the input string
base64Encode	base64Encode(string) string	base64 encoded version of the input
base64Decode	base64Decode(string) string	base64 decoded version of the input
jsonEncode	jsonEncode(string) string	json encoded version of the input
jsonDecode	jsonDecode(string) string	json decoded version of the input
includes	includes(arr list(any), element any) bool	returns whether the slice includes the element
replace	replace(text string, old string, new string) string	full string replacement of the old value with the new value
join	join(arr list(string), sep string) string	joins the array into a single string with the given separator
titleCase	titleCase(string) string	converts the input into title case string
lowerCase	lowerCase(string) string	converts the input into lower case string
upperCase	upperCase(string) string	converts the input into upper case string
trimSpace	trimSpace(string) string	removes white spaces from the input string
trimPrefix	trimPrefix(string) string	removes prefix from the input string
trimSuffix	trimSuffix(string) string	removes suffix from the input string
split	split(arr list(string), sep string) string	slices s into all substrings separated by sep and returns a slice of the substrings between those separators
geoDistance	geoDistance(this list(float64), that list(float64)) float64	haversine distance between two coordinates [lat,lng]
render	render(tmplate string, data map[string]interface) string	renders the input template with the provided data map

Documentation

Index

• Variables
• type Decision
  • func NewDecision(expression string) (*Decision, error)
  • func (n *Decision) Eval(data map[string]interface{}) error
  • func (e *Decision) Expression() string
• type FuncMap
• type Function
  • func NewFunction(decl *expr.Decl, overload *functions.Overload) *Function
• type Trigger
  • func NewTrigger(decision *Decision, triggerExpression string) (*Trigger, error)
  • func (e *Trigger) Expression() string
  • func (t *Trigger) Trigger(data map[string]interface{}) (map[string]interface{}, error)

Examples

• NewDecision
• NewTrigger

Variables

var (
	ErrDecisionDenied   = errors.New("trigger: evaluation = false")
	ErrEmptyExpressions = errors.New("trigger: empty expressions")
)

var Functions = FuncMap{
	"now": {
		// contains filtered or unexported fields
	},
	"uuid": {
		// contains filtered or unexported fields
	},
	"sha1": {
		// contains filtered or unexported fields
	},
	"sha256": {
		// contains filtered or unexported fields
	},
	"sha3": {
		// contains filtered or unexported fields
	},
	"base64Encode": {
		// contains filtered or unexported fields
	},
	"base64Decode": {
		// contains filtered or unexported fields
	},
	"jsonEncode": {
		// contains filtered or unexported fields
	},
	"jsonDecode": {
		// contains filtered or unexported fields
	},
	"includes": {
		// contains filtered or unexported fields
	},
	"replace": {
		// contains filtered or unexported fields
	},
	"join": {
		// contains filtered or unexported fields
	},
	"titleCase": {
		// contains filtered or unexported fields
	},
	"lowerCase": {
		// contains filtered or unexported fields
	},
	"upperCase": {
		// contains filtered or unexported fields
	},
	"trimSpace": {
		// contains filtered or unexported fields
	},
	"trimPrefix": {
		// contains filtered or unexported fields
	},
	"trimSuffix": {
		// contains filtered or unexported fields
	},
	"split": {
		// contains filtered or unexported fields
	},
	"geoDistance": {
		// contains filtered or unexported fields
	},
	"render": {
		// contains filtered or unexported fields
	},
}

Types

type Decision

type Decision struct {
	// contains filtered or unexported fields
}

Decision is used to evaluate boolean expressions

func NewDecision

func NewDecision(expression string) (*Decision, error)

NewDecision creates a new Decision with the given boolean CEL expressions

Example

package main

import (
	"fmt"
	"github.com/graphikDB/trigger"
)

func main() {
	decision, err := trigger.NewDecision("this.email.endsWith('acme.com')")
	if err != nil {
		fmt.Println(err.Error())
		return
	}
	if err := decision.Eval(map[string]interface{}{
		"name":  "bob",
		"email": "bob@acme.com",
	}); err != nil {
		fmt.Println(err.Error())
		return
	}
	fmt.Println(decision.Expression())
}

Output:

this.email.endsWith('acme.com')

func (*Decision) Eval

func (n *Decision) Eval(data map[string]interface{}) error

Eval evaluates the boolean CEL expressions against the Mapper

func (*Decision) Expression

func (e *Decision) Expression() string

Expressions returns the decsions raw expression

type FuncMap

type FuncMap map[string]*Function

type Function

type Function struct {
	// contains filtered or unexported fields
}

func NewFunction

func NewFunction(decl *expr.Decl, overload *functions.Overload) *Function

type Trigger

type Trigger struct {
	// contains filtered or unexported fields
}

Trigger creates values as map[string]interface{} if it's decisider returns no errors against a Mapper

func NewTrigger

func NewTrigger(decision *Decision, triggerExpression string) (*Trigger, error)

NewTrigger creates a new trigger instance from the decision & trigger expressions

Example

package main

import (
	"fmt"
	"github.com/graphikDB/trigger"
)

func main() {
	decision, err := trigger.NewDecision("this.email.endsWith('acme.com')")
	if err != nil {
		fmt.Println(err.Error())
		return
	}
	trigg, err := trigger.NewTrigger(decision, `
	{
		'admin': true,
		'updated_at': now(),
		'email_sha1': sha1("this.email"),
		'email_sha3': sha3("this.email"),
		'email_sha256': sha256("this.email")
	}
`)
	if err != nil {
		fmt.Println(err.Error())
		return
	}
	person := map[string]interface{}{
		"name":  "bob",
		"email": "bob@acme.com",
	}
	data, err := trigg.Trigger(person)
	if err != nil {
		fmt.Println(err.Error())
		return
	}
	fmt.Println(data["admin"], data["updated_at"].(int64) > 0, data["email_sha1"], data["email_sha3"], data["email_sha256"])
}

Output:

true true bbd5d1877fc1db4e1dc12fbd39dd0989cf422be5 1ec04699856dcbef0f32413a71b6c8a1228de6663f46159f0084b0ecbccb7a8ca3e7928028650ad318f2d52e2ed5b9edecfc46c088557e5fa640f94c3fec8c46 2fee51920dc7672e5c66b328a4b4fff0382c4552f893f7a92747a213085855dd

func (*Trigger) Expression

func (e *Trigger) Expression() string

Expression returns the triggers raw CEL expressions

func (*Trigger) Trigger

func (t *Trigger) Trigger(data map[string]interface{}) (map[string]interface{}, error)

Trigger executes it's decision against the Mapper and then overwrites the