started working on the amqp transport and subscriber bundle

Signed-off-by: Lukas <lukas.jarosch@mail.com>

.gitignore

@@ -1,2 +1,3 @@
 .idea
 bin/
+dist

README.md

@@ -52,6 +52,7 @@ Examples are now hosted in a separate repository: [godin-examples](https://githu
 |------|------|
 | **init** | initialize a new godin project in the current directory |
 | **update** | update the project in the current directory and regenerate necessary stuff |
+| **add** | add bundles to an existing project |
 | **version** | print godin version |
 | **help** | Help about any command |
 

cmd/add.go

@@ -0,0 +1,98 @@
+package cmd
+
+import (
+	"fmt"
+	"os"
+
+	"strings"
+
+	"github.com/lukasjarosch/godin/internal/bundle"
+	"github.com/lukasjarosch/godin/internal/godin"
+	"github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+)
+
+func init() {
+	rootCmd.AddCommand(addCommand)
+}
+
+// rootCmd represents the base command when called without any subcommands
+var addCommand = &cobra.Command{
+	Use:   "add",
+	Short: "Add bundles to an initalized godin project",
+	Long: `Add different kind of bundles to the current project. 
+
+	godin add <bundleType>
+
+The available bundles are:  
+  middleware: to add a new service-layer middleware 
+  datastore: to add a new datastore bundle (mysql, mongodb, redis)
+  subscriber: add an AMQP topic subscription
+  transport: to add a new transport layer`,
+	Run:  addCmd,
+	Args: cobra.MinimumNArgs(1),
+}
+
+var validBundleTypes = []string{"middleware", "datastore", "transport", "subscriber"}
+
+func addCmd(cmd *cobra.Command, args []string) {
+	logrus.SetLevel(logrus.DebugLevel)
+	// ensure a valid bundle type is passed
+	bundleType, err := validateBundleType(args[0])
+	if err != nil {
+		logrus.Error(err)
+		os.Exit(1)
+	}
+
+	// project must be initialized
+	if _, err := os.Stat(godin.ConfigFilename()); err != nil {
+		logrus.Fatal("project not initialized")
+	}
+
+	if err := godin.LoadConfiguration(); err != nil {
+		logrus.Fatalf("failed to load configuration: %s", err.Error())
+	}
+
+	switch bundleType {
+	case "middleware",
+		"datastore",
+		"transport":
+		logrus.Info("sorry, this bundle type is not yet implemented :(")
+	case "subscriber":
+
+		_, err := bundle.InitializeAMQPTransport()
+		if err != nil {
+			logrus.Errorf("failed to initialize AMQP transport: %s", err)
+		}
+
+		/*
+			sub, err := bundle.InitializeSubscriber()
+			if err != nil {
+				logrus.Errorf("failed to initialize subscriber: %s", err)
+				os.Exit(1)
+			}
+
+			// add to config
+			subscriptions := make(map[string]interface{})
+			if config.IsSet("transport.amqp.subscriptions") {
+				subscriptions = config.GetStringMap("transport.amqp.subscriptions")
+			}
+			subscriptions[sub.HandlerName] = sub.Subscription
+			config.Set("transport.amqp.subscriptions", subscriptions)
+			godin.SaveConfiguration()
+		*/
+	}
+}
+
+func validateBundleType(givenType string) (bundleType string, err error) {
+	for _, validType := range validBundleTypes {
+		if givenType == validType {
+			bundleType = validType
+			break
+		}
+	}
+	if bundleType == "" {
+		return "", fmt.Errorf("invalid bundle type, valid types are: %s", strings.Join(validBundleTypes, ", "))
+	}
+	return bundleType, nil
+}

cmd/update.go

@@ -37,7 +37,6 @@ var updateCommand = &cobra.Command{
 }
 
 func updateCmd(cmd *cobra.Command, args []string) {
-
 	logrus.SetLevel(logrus.DebugLevel)
 
 	// project must be initialized

go.mod

@@ -23,6 +23,7 @@ require (
 	github.com/sirupsen/logrus v1.4.2
 	github.com/spf13/cobra v0.0.5
 	github.com/spf13/viper v1.3.2
+	github.com/streadway/amqp v0.0.0-20190404075320-75d898a42a94
 	github.com/vetcher/go-astra v1.2.0
 	gopkg.in/alecthomas/kingpin.v3-unstable v3.0.0-20180810215634-df19058c872c // indirect
 )

go.sum

@@ -147,6 +147,8 @@ github.com/spf13/pflag v1.0.3 h1:zPAT6CGy6wXeQ7NtTnaTerfKOsV6V6F8agHXFiazDkg=
 github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
 github.com/spf13/viper v1.3.2 h1:VUFqw5KcqRf7i70GOzW7N+Q7+gxVBkSSqiXB12+JQ4M=
 github.com/spf13/viper v1.3.2/go.mod h1:ZiWeW+zYFKm7srdB9IoDzzZXaJaI5eL9QjNiN/DMA2s=
+github.com/streadway/amqp v0.0.0-20190404075320-75d898a42a94 h1:0ngsPmuP6XIjiFRNFYlvKwSr5zff2v+uPHaffZ6/M4k=
+github.com/streadway/amqp v0.0.0-20190404075320-75d898a42a94/go.mod h1:AZpEONHx3DKn8O/DFsRAY58/XVQiIPMTMB1SddzLXVw=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=

internal/bundle/datastore.go

@@ -0,0 +1,9 @@
+package bundle
+
+type datastore struct {
+}
+
+type MySQLDatastore struct {
+	datastore
+}
+

internal/bundle/middleware.go

@@ -0,0 +1 @@
+package bundle

internal/bundle/subscribe.go

@@ -0,0 +1,74 @@
+package bundle
+
+import (
+	"github.com/lukasjarosch/godin/internal/prompt"
+	"github.com/lukasjarosch/godin/pkg/amqp"
+)
+
+type subscriber struct {
+	Subscription amqp.Subscription
+	HandlerName  string `json:"handler_name"`
+}
+
+func InitializeSubscriber() (*subscriber, error) {
+	sub := amqp.Subscription{}
+	handlerName, err := promptValues(sub)
+	if err != nil {
+		return nil, err
+	}
+
+	return &subscriber{
+		Subscription: sub,
+		HandlerName:  handlerName,
+	}, nil
+}
+
+func promptValues(sub amqp.Subscription) (handlerName string, err error) {
+	// Topic
+	p := prompt.NewPrompt(
+		"AMQP subscription Topic",
+		"user.created",
+		prompt.Validate(),
+	)
+	topic, err := p.Run()
+	if err != nil {
+		return "", err
+	}
+	sub.Topic = topic
+
+	// Exchange
+	p = prompt.NewPrompt(
+		"AMQP Exchange name",
+		"user-Exchange",
+		prompt.Validate(),
+	)
+	exchange, err := p.Run()
+	if err != nil {
+		return "", err
+	}
+	sub.Exchange = exchange
+
+	// Queue
+	p = prompt.NewPrompt(
+		"AMQP Queue name which is bound to the Exchange",
+		"user-created-Queue",
+		prompt.Validate(),
+	)
+	queue, err := p.Run()
+	if err != nil {
+		return "", err
+	}
+	sub.Queue = queue
+
+	// HandlerName
+	p = prompt.NewPrompt(
+		"Name of the handler for this subscription",
+		"UserCreatedHandler",
+		prompt.Validate(),
+	)
+	handler, err := p.Run()
+	if err != nil {
+		return "", err
+	}
+	return handler, nil
+}

internal/bundle/transport.go

@@ -0,0 +1,64 @@
+package bundle
+
+import (
+	"fmt"
+
+	"github.com/lukasjarosch/godin/internal/prompt"
+	"github.com/sirupsen/logrus"
+	config "github.com/spf13/viper"
+	"github.com/lukasjarosch/godin/internal/godin"
+)
+
+const AmqpTransportKey = "transport.amqp"
+const AmqpExchangeKey = "transport.amqp.exchange"
+const AmqpExchangeTypeKey = "transport.amqp.exchange_type"
+const AmqpDefaultAddress = "transport.amqp.default_address"
+
+type amqpTransport struct {
+	DefaultAddress string `json:"default_address"`
+	Exchange       string `json:"exchange"`
+	ExchangeType   string `json:"exchange_type"`
+}
+
+func InitializeAMQPTransport() (transport *amqpTransport, err error) {
+	if config.IsSet(AmqpTransportKey) {
+		exchange := config.GetString(AmqpExchangeKey)
+		exchangeType := config.GetString(AmqpExchangeTypeKey)
+		defaultAddress := config.GetString(AmqpDefaultAddress)
+
+		logrus.Debug("AMQP transport is already configured, loading from config")
+
+		return &amqpTransport{
+			DefaultAddress: defaultAddress,
+			Exchange:       exchange,
+			ExchangeType:   exchangeType,
+		}, nil
+	}
+
+	transport = &amqpTransport{}
+	if err := promptAmqpTransportValues(transport); err != nil {
+		return nil, fmt.Errorf("error while prompting AMQP transport values: %s", err)
+	}
+
+	config.Set(AmqpExchangeKey, transport.Exchange)
+	config.Set(AmqpExchangeTypeKey, transport.ExchangeType)
+	config.Set(AmqpDefaultAddress, transport.DefaultAddress)
+	godin.SaveConfiguration()
+
+	return transport, nil
+}
+
+func promptAmqpTransportValues(transport *amqpTransport) (err error) {
+	// default AMQP server address
+	p := prompt.NewPrompt(
+		"AMQP default server address to use if AMQP_URL is not provided",
+		"amqp://username:password@host:port/vhost",
+		prompt.Validate(),
+	)
+	transport.DefaultAddress, err = p.Run()
+	if err != nil {
+		return err
+	}
+
+	return nil
+}

pkg/amqp/publish.go

@@ -0,0 +1 @@
+package amqp

pkg/amqp/subscribe.go

@@ -0,0 +1,84 @@
+package amqp
+
+import (
+	"github.com/streadway/amqp"
+)
+
+type SubscriberHandler func(delivery amqp.Delivery)
+
+type Subscription struct {
+	Topic          string `json:"topic"`
+	Exchange       string `json:"exchange"`
+	Queue          string `json:"queue"`
+}
+
+type handler struct {
+	implementation SubscriberHandler
+	done           chan error
+	ctag           string
+	routingKey     string
+}
+
+type Subscriber struct {
+	channel  *amqp.Channel
+	exchange string
+	handlers []handler
+}
+
+// NewSubscriber returns an AMQP publisher
+func NewSubscriber(channel *amqp.Channel, exchange string) Subscriber {
+	return Subscriber{
+		channel:  channel,
+		exchange: exchange,
+	}
+}
+
+func (c *Subscriber) Subscribe(queueName, routingKey string, ctag string, handler SubscriberHandler) error {
+	queue, err := c.channel.QueueDeclare(queueName, true, false, false, false, nil)
+	if err != nil {
+		return err
+	}
+
+	if err = c.channel.QueueBind(queue.Name, routingKey, c.exchange, false, nil); err != nil {
+		return err
+	}
+
+	deliveries, err := c.channel.Consume(queue.Name, ctag, false, false, false, false, nil)
+	if err != nil {
+		return err
+	}
+
+	h := c.addHandler(routingKey, ctag, handler)
+	go c.Handler(deliveries, h)
+
+	return nil
+}
+
+func (c *Subscriber) addHandler(routingKey string, ctag string, handlerImpl SubscriberHandler) handler {
+	h := handler{
+		routingKey:     routingKey,
+		ctag:           ctag,
+		implementation: handlerImpl,
+		done:           make(chan error),
+	}
+	c.handlers = append(c.handlers, h)
+
+	return h
+}
+
+func (c *Subscriber) Handler(deliveries <-chan amqp.Delivery, h handler) {
+	for d := range deliveries {
+		h.implementation(d)
+	}
+	h.done <- nil
+}
+
+func (c *Subscriber) Shutdown() error {
+	for _, h := range c.handlers {
+		if err := c.channel.Cancel(h.ctag, true); err != nil {
+			return err
+		}
+		<-h.done
+	}
+	return nil
+}