vine.go

// MIT License
//
// Copyright (c) 2020 Lack
//
// 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 vine is a pluggable framework for vine services
package vine

import (
	"context"

	"github.com/vine-io/vine/core/client"
	"github.com/vine-io/vine/core/server"
)

type serviceKey struct{}

// Service is an interface that wraps the lower level libraries
// within vine. It's a convenience method for building
// and initialising services.
type Service interface {
	// Name The service name
	Name() string
	// Options returns the current options
	Options() Options
	// Init initialises options
	Init(...Option) error
	// Server is for handling requests and events
	Server() server.Server
	// Client is used to call services
	Client() client.Client
	// Run the service
	Run() error
	// String The service implementation
	String() string
}

// Event is used to publish messages to topic
type Event interface {
	// Publish publishes a message to the event topic
	Publish(ctx context.Context, msg interface{}, opts ...client.PublishOption) error
}

// Option for vine
type Option func(*Options)

// NewService creates and returns a new Service based on the packages within.
func NewService(opts ...Option) Service {
	return newService(opts...)
}

// FromContext retrieves a Service from the Context.
func FromContext(ctx context.Context) (Service, bool) {
	s, ok := ctx.Value(serviceKey{}).(Service)
	return s, ok
}

// NewContext returns a new Context with the Service embedded within it.
func NewContext(ctx context.Context, s Service) context.Context {
	return context.WithValue(ctx, serviceKey{}, s)
}

// NewEvent creates a new event publisher
func NewEvent(topic string, c client.Client) Event {
	if c == nil {
		c = client.DefaultClient
	}
	return &event{c, topic}
}

// RegisterHandler is syntactic sugar for registering a handler
func RegisterHandler(s server.Server, h interface{}, opts ...server.HandlerOption) error {
	return s.Handle(s.NewHandler(h, opts...))
}

// RegisterSubscriber is syntactic sugar for registering a subscriber
func RegisterSubscriber(topic string, s server.Server, h interface{}, opts ...server.SubscriberOption) error {
	return s.Subscribe(s.NewSubscriber(topic, h, opts...))
}