From 8cfe2fe9164d2ad8750c79b8deb508b94417b7c5 Mon Sep 17 00:00:00 2001
From: Felipe Martinez <pipernene@gmail.com>
Date: Wed, 2 Dec 2020 16:37:36 +0100
Subject: [PATCH] Use discovery interface for client calls

---
 client/client.go       | 20 ++++++++++++++++----
 discovery/discovery.go |  6 ++++--
 options/options.go     |  6 +++++-
 service.go             |  2 +-
 4 files changed, 26 insertions(+), 8 deletions(-)

diff --git a/client/client.go b/client/client.go
index 6daaff0..e3c52fe 100644
--- a/client/client.go
+++ b/client/client.go
@@ -19,7 +19,7 @@ var ErrInvalidInput = errors.New("func must have 1 input")
 var ErrInputPointer = errors.New("the func must take a pointer as an input")
 
 type Client interface {
-	Call(ctx context.Context, service string, path string, req interface{}, resp interface{}, opts ...CallOption) error
+	Call(service string, path string, req interface{}, resp interface{}, opts ...CallOption) error
 	Subscribe(topic string, callback interface{})
 }
 
@@ -29,6 +29,7 @@ type client struct {
 	broker broker.Broker
 	log    logger.Logger
 	disc   discovery.Discovery
+	port   int16
 }
 
 type CallError struct {
@@ -45,10 +46,12 @@ func NewClient(opts *options.Options) Client {
 		trans:  opts.Transport,
 		broker: opts.Broker,
 		log:    opts.Logger,
+		disc:   opts.Discovery,
+		port:   opts.RPCPort,
 	}
 }
 
-func (c *client) Call(ctx context.Context, service string, path string, reqval interface{}, respval interface{}, opts ...CallOption) error {
+func (c *client) Call(service string, path string, reqval interface{}, respval interface{}, opts ...CallOption) error {
 	var callopts CallOptions
 
 	for _, o := range opts {
@@ -59,7 +62,16 @@ func (c *client) Call(ctx context.Context, service string, path string, reqval i
 		callopts.Context = context.Background()
 	}
 
-	s, err := c.trans.Dial(ctx, service)
+	if c.disc == nil {
+		panic("no discovery has been set up")
+	}
+
+	host, err := c.disc.Find(service)
+	if err != nil {
+		return fmt.Errorf("discover service: %w", err)
+	}
+
+	s, err := c.trans.Dial(callopts.Context, fmt.Sprintf("%s:%d", host, c.port))
 	if err != nil {
 		return fmt.Errorf("dial: %w", err)
 	}
@@ -80,7 +92,7 @@ func (c *client) Call(ctx context.Context, service string, path string, reqval i
 	}
 
 	var respmsg transport.Message
-	if err := s.Receive(ctx, &respmsg); err != nil {
+	if err := s.Receive(callopts.Context, &respmsg); err != nil {
 		return fmt.Errorf("receive message: %w", err)
 	}
 
diff --git a/discovery/discovery.go b/discovery/discovery.go
index 31e860f..ea2a687 100644
--- a/discovery/discovery.go
+++ b/discovery/discovery.go
@@ -1,7 +1,9 @@
 package discovery
 
-import "net"
+import "errors"
 
 type Discovery interface {
-	Find(svc string) (net.IP, error)
+	Find(svc string) (host string, err error)
 }
+
+var ErrServiceNotRegistered = errors.New("service not registered")
diff --git a/options/options.go b/options/options.go
index 5060fe1..cfdc3c6 100644
--- a/options/options.go
+++ b/options/options.go
@@ -24,6 +24,9 @@ type Options struct {
 	Discovery discovery.Discovery
 }
 
+// DefaultRPCPort is the port that will be used for RPC connections if no other is specified
+const DefaultRPCPort = 7070
+
 // Option represents a function that can be used to mutate an Options object
 type Option func(*Options)
 
@@ -34,7 +37,8 @@ func Name(name string) Option {
 	}
 }
 
-// RPCPort sets the port in which this service's RPC will listen on, as well as the port in which other services' RPC servers are listening on
+// RPCPort sets the port in which this service's RPC will listen on, as well as the port in which other services' RPC servers are listening on.
+// Defaults to DefaultRPCPort
 func RPCPort(port int16) Option {
 	return func(o *Options) {
 		o.RPCPort = port
diff --git a/service.go b/service.go
index d51120e..2f5b410 100644
--- a/service.go
+++ b/service.go
@@ -39,7 +39,7 @@ type service struct {
 func NewService(opts ...options.Option) Service {
 	svc := &service{}
 	svc.options.Logger = logger.NewStdoutLogger()
-	svc.options.RPCPort = 7070
+	svc.options.RPCPort = options.DefaultRPCPort
 
 	svc.Apply(opts...)