Verify that a rendered template is valid YAML (#1362)

* Verify that a rendered template is valid YAML

Co-Authored-By: Jan Schlicht <jan@d2iq.com>
Signed-off-by: Andreas Neumann <aneumann@mesosphere.com>

Makefile

@@ -47,10 +47,8 @@ test-clean:
 
 .PHONY: lint
 lint:
-ifeq (, $(shell which golangci-lint))
-	./hack/install-golangcilint.sh
-endif
-	golangci-lint run
+	if [ ! -f ${GOPATH}/bin/golangci-lint ]; then ./hack/install-golangcilint.sh; fi
+	${GOPATH}/bin/golangci-lint run
 
 .PHONY: download
 download:

pkg/kudoctl/packages/verifier/template/verify_render.go

@@ -38,10 +38,18 @@ func templateCompilable(pf *packages.Files) verifier.Result {
 
 	engine := renderer.New()
 	for k, v := range pf.Templates {
-		_, err := engine.Render(k, v, configs)
+		// Render the template
+		s, err := engine.Render(k, v, configs)
 		if err != nil {
 			res.AddErrors(err.Error())
 		}
+
+		// Try to parse rendered template as valid Kubernetes objects
+		_, err = renderer.YamlToObject(s)
+		if err != nil {
+			res.AddErrors(err.Error())
+		}
+
 	}
 
 	return res

pkg/kudoctl/packages/verifier/template/verify_render_test.go

@@ -30,3 +30,35 @@ func TestTemplateRenderVerifier(t *testing.T) {
 	assert.Equal(t, 1, len(res.Errors))
 	assert.Equal(t, `error rendering template: template: foo.yaml:2:6: executing "foo.yaml" at <eq>: wrong number of args for eq: want at least 1 got 0`, res.Errors[0])
 }
+
+func TestTemplateRenderVerifier_InvalidYAML(t *testing.T) {
+	params := make([]v1beta1.Parameter, 0)
+	paramFile := packages.ParamsFile{Parameters: params}
+	templates := make(map[string]string)
+	templates["foo.yaml"] = `
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: backup
+spec:
+  template:
+    spec:
+      containers:
+        - name: backup
+       restartPolicy: Never
+`
+	operator := packages.OperatorFile{}
+	pf := packages.Files{
+		Templates: templates,
+		Operator:  &operator,
+		Params:    &paramFile,
+	}
+	verifier := RenderVerifier{}
+	res := verifier.Verify(&pf)
+
+	assert.Equal(t, 0, len(res.Warnings))
+	assert.Equal(t, 1, len(res.Errors))
+	assert.Equal(t,
+		`decoding chunk "\napiVersion: batch/v1\nkind: Job\nmetadata:\n  name: backup\nspec:\n  template:\n    spec:\n      containers:\n        - name: backup\n`+
+			`       restartPolicy: Never\n" failed: error converting YAML to JSON: yaml: line 10: did not find expected key`, res.Errors[0])
+}