Merge pull request #21 from nginxinc/add-lint

Add lint option to Makefile and fix lint issues

Author: Rulox

CONTRIBUTING.md

@@ -67,3 +67,4 @@ Note: if you’d like to implement a new feature, please consider creating a fea
 * Run `gofmt` over your code to automatically resolve a lot of style issues. Most editors support this running automatically when saving a code file.
 * Run `go lint` and `go vet` on your code too to catch any other issues.
 * Follow this guide on some good practice and idioms for Go -  https://github.com/golang/go/wiki/CodeReviewComments
+* To check for extra issues, install [golangci-lint](https://github.com/golangci/golangci-lint) and run `make lint` or `golangci-lint run`

Makefile

@@ -11,6 +11,9 @@ else
 	go test ./...
 endif
 
+lint:
+	golangci-lint run
+
 compile: test
 ifeq ($(BUILD_IN_CONTAINER),1)
 	$(GO_DOCKER_RUN) $(GOLANG_CONTAINER) go build -o /build_output/nginx-asg-sync

cmd/sync/aws.go

@@ -91,9 +91,7 @@ func (client *AWSClient) getInstancesOfAutoscalingGroup(group *autoscaling.Group
 		return result, err
 	}
 	for _, res := range resp.Reservations {
-		for _, ins := range res.Instances {
-			result = append(result, ins)
-		}
+		result = append(result, res.Instances...)
 	}
 
 	return result, nil

cmd/sync/main.go

@@ -58,7 +58,11 @@ func main() {
 		os.Exit(10)
 	}
 
-	awsClient := createAWSClient(cfg.Region)
+	awsClient, err := createAWSClient(cfg.Region)
+	if err != nil {
+		log.Printf("Couldn't create AWS client: %v", err)
+		os.Exit(10)
+	}
 
 	for _, ups := range cfg.Upstreams {
 		if ups.Kind == "http" {
@@ -142,11 +146,16 @@ func main() {
 	}
 }
 
-func createAWSClient(region string) *AWSClient {
+func createAWSClient(region string) (*AWSClient, error) {
 	httpClient := &http.Client{Timeout: connTimeoutInSecs * time.Second}
 	cfg := &aws.Config{Region: aws.String(region), HTTPClient: httpClient}
-	session := session.New(cfg)
+
+	session, err := session.NewSession(cfg)
+	if err != nil {
+		return nil, err
+	}
+
 	svcAutoscaling := autoscaling.New(session)
 	svcEC2 := ec2.New(session)
-	return NewAWSClient(svcEC2, svcAutoscaling)
+	return NewAWSClient(svcEC2, svcAutoscaling), nil
 }