added SessionProvider (#8)

* added SessionProvider

* added SessionProviderFun docs and example

Author: jdoklovic

.gitignore

@@ -0,0 +1 @@
+.vscode

config.go

@@ -10,8 +10,15 @@ import (
 	"github.com/aws/aws-sdk-go/aws/session"
 )
 
+// SessionProviderFunc can be used to add custom AWS session setup to the gosqs.Config.
+// Callers simply need to implement this function type and set it as Config.SessionProvider.
+// If Config.SessionProvider is not set (is nil), a default provider based on AWS Key/Secret will be used.
+type SessionProviderFunc func(c Config) (*session.Session, error)
+
 // Config defines the gosqs configuration
 type Config struct {
+	// a way to provide custom session setup. A default based on key/secret will be used if not provided
+	SessionProvider SessionProviderFunc
 	// private key to access aws
 	Key string
 	// secret to access aws
@@ -108,7 +115,8 @@ func (r retryer) MaxRetries() int {
 	return 10
 }
 
-// newSession creates a new aws session
+// newSession creates a new aws session.
+// This will be used as the default SessionProvider if one is not set
 func newSession(c Config) (*session.Session, error) {
 	//sets credentials
 	creds := credentials.NewStaticCredentials(c.Key, c.Secret, "")

consumer.go

@@ -57,7 +57,12 @@ type consumer struct {
 // NewConsumer creates a new SQS instance and provides a configured consumer interface for
 // receiving and sending messages
 func NewConsumer(c Config, queueName string) (Consumer, error) {
-	sess, err := newSession(c)
+	if c.SessionProvider == nil {
+		c.SessionProvider = newSession
+	}
+
+	sess, err := c.SessionProvider(c)
+
 	if err != nil {
 		return nil, err
 	}

consumer_test.go

@@ -5,6 +5,10 @@ import (
 	"testing"
 	"time"
 
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/credentials"
+	"github.com/aws/aws-sdk-go/aws/request"
+	"github.com/aws/aws-sdk-go/aws/session"
 	"github.com/aws/aws-sdk-go/service/sqs"
 )
 
@@ -84,6 +88,39 @@ func TestNewConsumer(t *testing.T) {
 	}
 }
 
+func TestNewConsumerWithSessionProvider(t *testing.T) {
+	provider := func(c Config) (*session.Session, error) {
+		creds := credentials.NewStaticCredentials("mykey", "mysecret", "")
+		_, err := creds.Get()
+		if err != nil {
+			return nil, ErrInvalidCreds.Context(err)
+		}
+
+		r := &retryer{retryCount: c.RetryCount}
+
+		cfg := request.WithRetryer(aws.NewConfig().WithRegion("us-west2").WithCredentials(creds), r)
+
+		hostname := "http://localhost:4100"
+		cfg.Endpoint = &hostname
+
+		return session.NewSession(cfg)
+	}
+
+	conf := Config{
+		SessionProvider: provider,
+		Env:             "dev",
+	}
+
+	c, err := NewConsumer(conf, "post-worker")
+	if err != nil {
+		t.Fatalf("error creating consumer, got %v", err)
+	}
+	expected := "http://local.goaws:4100/queue/dev-post-worker"
+	if c.(*consumer).QueueURL != expected {
+		t.Fatalf("did not properly apply http result, expected %s, got %s", expected, c.(*consumer).QueueURL)
+	}
+}
+
 func TestRegisterHandler(t *testing.T) {
 	c := getConsumer(t)
 	a := []Adapter{}

examples/session_provider.go

@@ -0,0 +1,46 @@
+package example
+
+import (
+	"github.com/aws/aws-sdk-go/aws"
+	"github.com/aws/aws-sdk-go/aws/credentials"
+	"github.com/aws/aws-sdk-go/aws/session"
+	"github.com/qhenkart/gosqs"
+)
+
+func main_with_session_provider() {
+
+	// implement a custom AWS session provider function
+	provider := func(c gosqs.Config) (*session.Session, error) {
+
+		// note: this implementation just hardcodes key and secret, but it could do anything
+		creds := credentials.NewStaticCredentials("mykey", "mysecret", "")
+		_, err := creds.Get()
+		if err != nil {
+			return nil, gosqs.ErrInvalidCreds.Context(err)
+		}
+
+		cfg := aws.NewConfig().WithRegion("us-west-1").WithCredentials(creds)
+
+		hostname := "http://localhost:4150"
+		cfg.Endpoint = &hostname
+
+		return session.NewSession(cfg)
+	}
+
+	// create the gosqs Config with our custom SessionProviderFunc
+	c := gosqs.Config{
+		// for emulation only
+		// Hostname: "http://localhost:4150",
+
+		SessionProvider: provider,
+		TopicARN:        "arn:aws:sns:local:000000000000:dispatcher",
+		Region:          "us-west-1",
+	}
+
+	//follows the flow to see how a worker should be configured and operate
+	initWorker(c)
+
+	//follows the flow to see how an http service should be configured and operate
+	initService(c)
+
+}

publisher.go

@@ -55,7 +55,12 @@ type publisher struct {
 
 // NewPublisher creates a new SQS/SNS publisher instance
 func NewPublisher(c Config) (Publisher, error) {
-	sess, err := newSession(c)
+	if c.SessionProvider == nil {
+		c.SessionProvider = newSession
+	}
+
+	sess, err := c.SessionProvider(c)
+
 	if err != nil {
 		return nil, err
 	}