ref(pkg/healthsrv): refactor *s3.S3 out of the health server

Put the S3 functionality behind a small interface so that the server
can be unit tested later

Author: Aaron Schlesinger

pkg/healthsrv/buckets_lister.go

@@ -0,0 +1,11 @@
+package healthsrv
+
+import (
+	s3 "github.com/aws/aws-sdk-go/service/s3"
+)
+
+// BucketLister is a *(github.com/aws/aws-sdk-go/service/s3).Client compatible interface that provides just the ListBuckets cross-section of functionality. It can also be implemented for unit tests
+type BucketLister interface {
+	// ListBuckets lists all the buckets in the object storage system
+	ListBuckets(*s3.ListBucketsInput) (*s3.ListBucketsOutput, error)
+}

pkg/healthsrv/healthz_handler.go

@@ -29,9 +29,9 @@ type healthZResp struct {
 	S3Buckets  []healthZRespBucket `json:"s3_buckets"`
 }
 
-func healthZHandler(nsLister NamespaceLister, s3Client *s3.S3) http.Handler {
+func healthZHandler(nsLister NamespaceLister, bLister BucketLister) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		lbOut, err := s3Client.ListBuckets(&s3.ListBucketsInput{})
+		lbOut, err := bLister.ListBuckets(&s3.ListBucketsInput{})
 		if err != nil {
 			str := fmt.Sprintf("Error listing buckets (%s)", err)
 			log.Err(str)

pkg/healthsrv/namespace_lister.go

@@ -6,6 +6,8 @@ import (
 	"k8s.io/kubernetes/pkg/labels"
 )
 
+// NamespaceLister is an (*k8s.io/kubernetes/pkg/client/unversioned).Client compatible interface that provides just the ListBuckets cross-section of functionality. It can also be implemented for unit tests.
 type NamespaceLister interface {
+	// List lists all namespaces that are selected by the given label and field selectors
 	List(labels.Selector, fields.Selector) (*api.NamespaceList, error)
 }

pkg/healthsrv/server.go

@@ -3,8 +3,6 @@ package healthsrv
 import (
 	"fmt"
 	"net/http"
-
-	s3 "github.com/aws/aws-sdk-go/service/s3"
 )
 
 const (
@@ -13,9 +11,9 @@ const (
 )
 
 // Start starts the healthcheck server on $host:$port and blocks. It only returns if the server fails, with the indicative error
-func Start(port int, nsLister NamespaceLister, s3Client *s3.S3) error {
+func Start(port int, nsLister NamespaceLister, bLister BucketLister) error {
 	mux := http.NewServeMux()
-	mux.Handle("/healthz", healthZHandler(nsLister, s3Client))
+	mux.Handle("/healthz", healthZHandler(nsLister, bLister))
 
 	hostStr := fmt.Sprintf(":%d", port)
 	return http.ListenAndServe(hostStr, mux)