refactor packages structure to avoid cyclic dependecies (#358)

This commit changes the structure of the code to avoid cyclic dependencies. All domain objects are now in function, event and subscription package without external dependencies. Function and Subscription service backed by libkv is in libkv package.

Author: mthenw

api/config.go

@@ -7,19 +7,20 @@ import (
 	"strings"
 	"time"
 
+	"github.com/serverless/event-gateway/router"
 	"github.com/serverless/libkv"
 	"github.com/serverless/libkv/store"
 	etcd "github.com/serverless/libkv/store/etcd/v3"
 	"go.uber.org/zap"
 	"go.uber.org/zap/zapcore"
 
-	"github.com/serverless/event-gateway/api"
+	"github.com/serverless/event-gateway/httpapi"
 	"github.com/serverless/event-gateway/internal/cache"
 	"github.com/serverless/event-gateway/internal/embedded"
-	"github.com/serverless/event-gateway/internal/httpapi"
+	intstore "github.com/serverless/event-gateway/internal/store"
 	"github.com/serverless/event-gateway/internal/sync"
+	eventgateway "github.com/serverless/event-gateway/libkv"
 	"github.com/serverless/event-gateway/plugin"
-	"github.com/serverless/event-gateway/router"
 )
 
 var version = "dev"
@@ -67,7 +68,8 @@ func main() {
 		embedded.EmbedEtcd(*embedDataDir, *embedPeerAddr, *embedCliAddr, shutdownGuard)
 	}
 
-	kv, err := libkv.NewStore(
+	// KV store
+	kvstore, err := libkv.NewStore(
 		store.ETCDV3,
 		strings.Split(*dbHosts, ","),
 		&store.Config{
@@ -78,28 +80,34 @@ func main() {
 		log.Fatal("Cannot create KV client.", zap.Error(err))
 	}
 
+	// Implementation of function and subscription services
+	service := &eventgateway.Service{
+		FunctionStore:     intstore.NewPrefixed("/serverless-event-gateway/functions", kvstore),
+		SubscriptionStore: intstore.NewPrefixed("/serverless-event-gateway/subscriptions", kvstore),
+		EndpointStore:     intstore.NewPrefixed("/serverless-event-gateway/endpoints", kvstore),
+		Log:               log,
+	}
+
+	// Plugin manager
 	pluginManager := plugin.NewManager(plugins, log)
 	err = pluginManager.Connect()
 	if err != nil {
 		log.Fatal("Loading plugins failed.", zap.Error(err))
 	}
 
-	targetCache := cache.NewTarget("/serverless-event-gateway", kv, log)
+	// Router
+	targetCache := cache.NewTarget("/serverless-event-gateway", kvstore, log)
 	router := router.New(*workersNumber, *workersBacklog, targetCache, pluginManager, log)
 	router.StartWorkers()
 
-	api.StartEventsAPI(httpapi.Config{
-		KV:            kv,
-		Log:           log,
+	httpapi.StartEventsAPI(router, httpapi.ServerConfig{
 		TLSCrt:        eventsTLSCrt,
 		TLSKey:        eventsTLSKey,
 		Port:          *eventsPort,
 		ShutdownGuard: shutdownGuard,
-	}, router)
+	})
 
-	api.StartConfigAPI(httpapi.Config{
-		KV:            kv,
-		Log:           log,
+	httpapi.StartConfigAPI(service, service, httpapi.ServerConfig{
 		TLSCrt:        configTLSCrt,
 		TLSKey:        configTLSKey,
 		Port:          *configPort,

api/metrics.go

@@ -10,7 +10,8 @@ import (
 	uuid "github.com/satori/go.uuid"
 )
 
-// Event is a default event structure. All data that passes through the Event Gateway is formatted as an Event, based on this schema.
+// Event is a default event structure. All data that passes through the Event Gateway is formatted as an Event, based on
+// this schema.
 type Event struct {
 	Type       Type        `json:"event"`
 	ID         string      `json:"id"`
@@ -19,8 +20,8 @@ type Event struct {
 	DataType   string      `json:"dataType"`
 }
 
-// NewEvent return new instance of Event.
-func NewEvent(eventType Type, mime string, payload interface{}) *Event {
+// New return new instance of Event.
+func New(eventType Type, mime string, payload interface{}) *Event {
 	return &Event{
 		Type:       eventType,
 		ID:         uuid.NewV4().String(),

cmd/event-gateway/main.go

@@ -3,10 +3,10 @@ package event
 import (
 	"net/http"
 
-	"github.com/serverless/event-gateway/functions"
+	"github.com/serverless/event-gateway/function"
 )
 
-// SystemEventReceivedType is a system event emmited when the Event Gateway receives an event.
+// SystemEventReceivedType is a system event emitted when the Event Gateway receives an event.
 const SystemEventReceivedType = Type("gateway.event.received")
 
 // SystemEventReceivedData struct.
@@ -16,31 +16,31 @@ type SystemEventReceivedData struct {
 	Headers http.Header `json:"header"`
 }
 
-// SystemFunctionInvokingType is a system event emmited before invoking a function.
+// SystemFunctionInvokingType is a system event emitted before invoking a function.
 const SystemFunctionInvokingType = Type("gateway.function.invoking")
 
 // SystemFunctionInvokingData struct.
 type SystemFunctionInvokingData struct {
-	FunctionID functions.FunctionID `json:"functionId"`
-	Event      Event                `json:"event"`
+	FunctionID function.ID `json:"functionId"`
+	Event      Event       `json:"event"`
 }
 
-// SystemFunctionInvokedType is a system event emmited after successful function invocation.
+// SystemFunctionInvokedType is a system event emitted after successful function invocation.
 const SystemFunctionInvokedType = Type("gateway.function.invoked")
 
 // SystemFunctionInvokedData struct.
 type SystemFunctionInvokedData struct {
-	FunctionID functions.FunctionID `json:"functionId"`
-	Event      Event                `json:"event"`
-	Result     []byte               `json:"result"`
+	FunctionID function.ID `json:"functionId"`
+	Event      Event       `json:"event"`
+	Result     []byte      `json:"result"`
 }
 
-// SystemFunctionInvocationFailedType is a system event emmited after successful function invocation.
+// SystemFunctionInvocationFailedType is a system event emitted after successful function invocation.
 const SystemFunctionInvocationFailedType = Type("gateway.function.invocationFailed")
 
 // SystemFunctionInvocationFailedData struct.
 type SystemFunctionInvocationFailedData struct {
-	FunctionID functions.FunctionID `json:"functionId"`
-	Event      Event                `json:"event"`
-	Error      []byte               `json:"result"`
+	FunctionID function.ID `json:"functionId"`
+	Event      Event       `json:"event"`
+	Error      []byte      `json:"result"`
 }

event/event.go

@@ -1,59 +1,59 @@
-package functions
+package function
 
 import (
 	"fmt"
 )
 
-// ErrNotFound occurs when function couldn't been found in the discovery.
-type ErrNotFound struct {
-	ID FunctionID
+// ErrFunctionNotFound occurs when function couldn't been found in the discovery.
+type ErrFunctionNotFound struct {
+	ID ID
 }
 
-func (e ErrNotFound) Error() string {
+func (e ErrFunctionNotFound) Error() string {
 	return fmt.Sprintf("Function %q not found.", string(e.ID))
 }
 
-// ErrAlreadyRegistered occurs when function with specified name is already registered..
-type ErrAlreadyRegistered struct {
-	ID FunctionID
+// ErrFunctionAlreadyRegistered occurs when function with specified name is already registered.
+type ErrFunctionAlreadyRegistered struct {
+	ID ID
 }
 
-func (e ErrAlreadyRegistered) Error() string {
+func (e ErrFunctionAlreadyRegistered) Error() string {
 	return fmt.Sprintf("Function %q already registered.", string(e.ID))
 }
 
-// ErrValidation occurs when function payload doesn't validate.
-type ErrValidation struct {
-	message string
+// ErrFunctionValidation occurs when function payload doesn't validate.
+type ErrFunctionValidation struct {
+	Message string
 }
 
-func (e ErrValidation) Error() string {
-	return fmt.Sprintf("Function doesn't validate. Validation error: %q", e.message)
+func (e ErrFunctionValidation) Error() string {
+	return fmt.Sprintf("Function doesn't validate. Validation error: %q", e.Message)
 }
 
 // ErrFunctionCallFailed occurs when function call failed because of provider error.
 type ErrFunctionCallFailed struct {
-	original error
+	Original error
 }
 
 func (e ErrFunctionCallFailed) Error() string {
-	return fmt.Sprintf("Function call failed. Error: %q", e.original)
+	return fmt.Sprintf("Function call failed. Error: %q", e.Original)
 }
 
 // ErrFunctionProviderError occurs when function call failed because of provider error.
 type ErrFunctionProviderError struct {
-	original error
+	Original error
 }
 
 func (e ErrFunctionProviderError) Error() string {
-	return fmt.Sprintf("Function call failed because of provider error. Error: %q", e.original)
+	return fmt.Sprintf("Function call failed because of provider error. Error: %q", e.Original)
 }
 
 // ErrFunctionError occurs when function call failed because of function error.
 type ErrFunctionError struct {
-	original error
+	Original error
 }
 
 func (e ErrFunctionError) Error() string {
-	return fmt.Sprintf("Function call failed because of runtime error. Error: %q", e.original)
+	return fmt.Sprintf("Function call failed because of runtime error. Error: %q", e.Original)
 }