Allow loading file from http

api/internal/target/kusttarget.go

@@ -7,7 +7,6 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
-	"log"
 	"strings"
 
 	"github.com/pkg/errors"
@@ -302,18 +301,15 @@ func (kt *KustTarget) configureExternalTransformers() ([]resmap.Transformer, err
 func (kt *KustTarget) accumulateResources(
 	ra *accumulator.ResAccumulator, paths []string) error {
 	for _, path := range paths {
-		ldr, err := kt.ldr.New(path)
-		if err == nil {
-			err = kt.accumulateDirectory(ra, ldr)
-			if err != nil {
-				return err
+		// try loading resource as file then as base (directory or git repository)
+		if errF := kt.accumulateFile(ra, path); errF != nil {
+			ldr, errL := kt.ldr.New(path)
+			if errL != nil {
+				return fmt.Errorf("accumulateFile %q, loader.New %q", errF, errL)
 			}
-		} else {
-			err2 := kt.accumulateFile(ra, path)
-			if err2 != nil {
-				// Log ldr.New() error to highlight git failures.
-				log.Print(err.Error())
-				return err2
+			errD := kt.accumulateDirectory(ra, ldr)
+			if errD != nil {
+				return fmt.Errorf("accumulateFile %q, accumulateDirector: %q", errF, errD)
 			}
 		}
 	}

api/krusty/accumulation_test.go

@@ -74,7 +74,7 @@ spec:
 	if err == nil {
 		t.Fatalf("expected an error")
 	}
-	if !IsMissingKustomizationFileError(err) {
+	if !strings.Contains(err.Error(), "accumulating resources") {
 		t.Fatalf("unexpected error: %q", err)
 	}
 }
@@ -89,7 +89,7 @@ resources:
 	if err == nil {
 		t.Fatalf("expected an error")
 	}
-	if !strings.Contains(err.Error(), "'/app/deployment.yaml' doesn't exist") {
+	if !strings.Contains(err.Error(), "accumulating resources") {
 		t.Fatalf("unexpected error: %q", err)
 	}
 }

api/loader/fileloader.go

@@ -5,7 +5,10 @@ package loader
 
 import (
 	"fmt"
+	"io/ioutil"
 	"log"
+	"net/http"
+	"net/url"
 	"path/filepath"
 	"strings"
 
@@ -86,6 +89,9 @@ type fileLoader struct {
 	// File system utilities.
 	fSys filesys.FileSystem
 
+	// Used to load from HTTP
+	http *http.Client
+
 	// Used to clone repositories.
 	cloner git.Cloner
 
@@ -293,6 +299,25 @@ func (fl *fileLoader) errIfRepoCycle(newRepoSpec *git.RepoSpec) error {
 // else an error.  Relative paths are taken relative
 // to the root.
 func (fl *fileLoader) Load(path string) ([]byte, error) {
+	if u, err := url.Parse(path); err == nil && (u.Scheme == "http" || u.Scheme == "https") {
+		var hc *http.Client
+		if fl.http != nil {
+			hc = fl.http
+		} else {
+			hc = &http.Client{}
+		}
+		resp, err := hc.Get(path)
+		if err != nil {
+			return nil, err
+		}
+		defer resp.Body.Close()
+		body, err := ioutil.ReadAll(resp.Body)
+		if err != nil {
+			return nil, err
+		}
+		return body, nil
+	}
+
 	if !filepath.IsAbs(path) {
 		path = fl.root.Join(path)
 	}

api/loader/fileloader_test.go

@@ -4,7 +4,9 @@
 package loader
 
 import (
+	"bytes"
 	"io/ioutil"
+	"net/http"
 	"os"
 	"path"
 	"path/filepath"
@@ -54,6 +56,7 @@ func makeLoader() *fileLoader {
 	return NewFileLoaderAtRoot(MakeFakeFs(testCases))
 
 }
+
 func TestLoaderLoad(t *testing.T) {
 	l1 := makeLoader()
 	if "/" != l1.Root() {
@@ -579,3 +582,93 @@ func TestRepoIndirectCycleDetection(t *testing.T) {
 		t.Fatalf("unexpected err: %v", err)
 	}
 }
+
+// Inspired by https://hassansin.github.io/Unit-Testing-http-client-in-Go
+type fakeRoundTripper func(req *http.Request) *http.Response
+
+func (f fakeRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	return f(req), nil
+}
+
+func makeFakeHTTPClient(fn fakeRoundTripper) *http.Client {
+	return &http.Client{
+		Transport: fn,
+	}
+}
+
+// TestLoaderHTTP test http file loader
+func TestLoaderHTTP(t *testing.T) {
+	var testCasesFile = []testData{
+		{
+			path:            "http/file.yaml",
+			expectedContent: "file content",
+		},
+	}
+
+	l1 := NewFileLoaderAtRoot(MakeFakeFs(testCasesFile))
+	if "/" != l1.Root() {
+		t.Fatalf("incorrect root: '%s'\n", l1.Root())
+	}
+	for _, x := range testCasesFile {
+		b, err := l1.Load(x.path)
+		if err != nil {
+			t.Fatalf("unexpected load error: %v", err)
+		}
+		if !reflect.DeepEqual([]byte(x.expectedContent), b) {
+			t.Fatalf("in load expected %s, but got %s", x.expectedContent, b)
+		}
+	}
+
+	var testCasesHTTP = []testData{
+		{
+			path:            "http://example.com/resource.yaml",
+			expectedContent: "http content",
+		},
+		{
+			path:            "https://example.com/resource.yaml",
+			expectedContent: "https content",
+		},
+	}
+
+	for _, x := range testCasesHTTP {
+		hc := makeFakeHTTPClient(func(req *http.Request) *http.Response {
+			u := req.URL.String()
+			if x.path != u {
+				t.Fatalf("expected URL %s, but got %s", x.path, u)
+			}
+			return &http.Response{
+				StatusCode: 200,
+				Body:       ioutil.NopCloser(bytes.NewBufferString(x.expectedContent)),
+				Header:     make(http.Header),
+			}
+		})
+		l2 := l1
+		l2.http = hc
+		b, err := l2.Load(x.path)
+		if err != nil {
+			t.Fatalf("unexpected load error: %v", err)
+		}
+		if !reflect.DeepEqual([]byte(x.expectedContent), b) {
+			t.Fatalf("in load expected %s, but got %s", x.expectedContent, b)
+		}
+	}
+
+	var testCaseUnsupported = []testData{
+		{
+			path:            "httpsnotreal://example.com/resource.yaml",
+			expectedContent: "invalid",
+		},
+	}
+	for _, x := range testCaseUnsupported {
+		hc := makeFakeHTTPClient(func(req *http.Request) *http.Response {
+			t.Fatalf("unexpected request to URL %s", req.URL.String())
+			return nil
+		})
+		l2 := l1
+		l2.http = hc
+		_, err := l2.Load(x.path)
+		if err == nil {
+			t.Fatalf("expect error but get %v", err)
+		}
+	}
+}

examples/loadHttp.md

@@ -0,0 +1,25 @@
+# load file from http
+
+Resource and patch files could be loaded from http
+
+<!-- @loadHttp -->
+```sh
+DEMO_HOME=$(mktemp -d)
+
+cat <<EOF >$DEMO_HOME/kustomization.yaml
+resources:
+- https://raw.githubusercontent.com/kubernetes-sigs/kustomize/master/examples/helloWorld/configMap.yaml
+EOF
+```
+
+<!-- @loadHttp -->
+```sh
+test 1 == \
+  $(kustomize build $DEMO_HOME | grep "Good Morning!" | wc -l); \
+  echo $?
+```
+
+Kustomize will try loading resource as a file either from local or http. If it
+fails, try to load it as a directory or git repository.
+
+Http load applies to patches as well. See full example in [loadHttp](loadHttp/).

examples/loadHttp/kustomization.yaml

@@ -0,0 +1,15 @@
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+resources:
+- https://raw.githubusercontent.com/kubernetes-sigs/kustomize/master/examples/wordpress/wordpress/deployment.yaml
+- https://github.com/knative/serving/releases/download/v0.12.0/serving.yaml # redirects to s3
+patches:
+- https://raw.githubusercontent.com/kubernetes-sigs/kustomize/master/examples/wordpress/patch.yaml
+patchesStrategicMerge:
+- |-
+  apiVersion: rbac.authorization.k8s.io/v1
+  kind: RoleBinding
+  metadata:
+    name: custom-metrics-auth-reader
+    namespace: kube-system
+  $patch: delete