condition

README

condition

Contains interfaces and methods for evaluating data using success or failure criteria. Conditions combine inspectors (e.g. string equals "foo", string matches "^foo") and an operator (e.g., all, any) to check the state of data before applying other functions.

Documentation

Overview

Package condition provides functions for evaluating data.

Index

• type Config
• type Operator
  • func New(ctx context.Context, cfg Config) (Operator, error)

Examples

• Operator

Types

type Config

type Config struct {
	Operator   string          `json:"operator"`
	Inspectors []config.Config `json:"inspectors"`
}

type Operator

type Operator interface {
	Operate(context.Context, *message.Message) (bool, error)
}

Example

package main

import (
	"context"
	"fmt"

	"github.com/brexhq/substation/condition"
	"github.com/brexhq/substation/config"
	"github.com/brexhq/substation/message"
)

func main() {
	ctx := context.TODO()

	// Multiple inspectors can be chained together with an operator.
	// This example uses the "all" operator, which requires all inspectors to
	// return true for the operator to return true.
	cfg := condition.Config{
		Operator: "all",
		Inspectors: []config.Config{
			{
				Type: "number_length_less_than",
				Settings: map[string]interface{}{
					"value": 10,
				},
			},
			{
				Type: "string_contains",
				Settings: map[string]interface{}{
					"value": "f",
				},
			},
		},
	}

	// Operators are retrieved from the factory and
	// applied to a message.
	op, err := condition.New(ctx, cfg)
	if err != nil {
		// handle err
		panic(err)
	}

	msg := message.New().SetData([]byte("fizzy"))
	if err != nil {
		// handle err
		panic(err)
	}

	ok, err := op.Operate(ctx, msg)
	if err != nil {
		// handle err
		panic(err)
	}

	fmt.Println(ok)
}

Output:

true

func New

func New(ctx context.Context, cfg Config) (Operator, error)

New returns a configured Operator from an Operator configuration.