feat: add support for multiple inline templates

README.md

@@ -48,7 +48,8 @@ spec:
 This function can load templates from three sources: `Inline`, `FileSystem` and `Environment`.
 
 Use the `Inline` source to specify a simple template inline in your Composition.
-Multiple YAML manifests can be specified using the `---` document separator.
+Multiple YAML manifests can be specified using the `templates` field, which may contain a slice of
+strings, or by using the `---` document separator in the `template` field.
 
 Use the `FileSystem` source to specify a directory of templates. The
 `FileSystem` source treats all files under the specified directory as templates.

example/inline-templates/composition.yaml

@@ -0,0 +1,19 @@
+apiVersion: apiextensions.crossplane.io/v1
+kind: Composition
+metadata:
+  name: example-inline
+spec:
+  mode: Pipeline
+  compositeTypeRef:
+    apiVersion: example.crossplane.io/v1beta1
+    kind: XR
+  pipeline:
+    - step: render-templates
+      functionRef:
+        name: function-go-templating
+      input:
+        apiVersion: gotemplating.fn.crossplane.io/v1beta1
+        kind: GoTemplate
+        source: Inline
+        inline:
+          templates: [] # Kustomize will add the templates here

example/inline-templates/kustomization.yaml

@@ -0,0 +1,10 @@
+apiVersion: kustomize.config.k8s.io/v1beta1
+kind: Kustomization
+
+resources:
+  - composition.yaml
+patches:
+  - path: templates/user.patch.yaml
+    target: { kind: Composition, name: example-inline }
+  - path: templates/access-key.patch.yaml
+    target: { kind: Composition, name: example-inline }

example/inline-templates/templates/access-key.patch.yaml

@@ -0,0 +1,10 @@
+- op: add
+  path: /spec/pipeline/0/input/inline/templates/-
+  value: |
+    apiVersion: iam.aws.upbound.io/v1beta1
+    kind: AccessKey
+    metadata:
+      annotations:
+        gotemplating.fn.crossplane.io/composition-resource-name: access-key
+    spec:
+      forProvider: {}

example/inline-templates/templates/user.patch.yaml

@@ -0,0 +1,10 @@
+- op: add
+  path: /spec/pipeline/0/input/inline/templates/-
+  value: |
+    apiVersion: iam.aws.upbound.io/v1beta1
+    kind: User
+    metadata:
+      annotations:
+        gotemplating.fn.crossplane.io/composition-resource-name: user
+    spec:
+      forProvider: {}

fn_test.go

@@ -139,7 +139,7 @@ func TestRunFunction(t *testing.T) {
 					Results: []*fnv1.Result{
 						{
 							Severity: fnv1.Severity_SEVERITY_FATAL,
-							Message:  "invalid function input: inline.template should be provided",
+							Message:  "invalid function input: inline.template or inline.templates should be provided",
 							Target:   fnv1.Target_TARGET_COMPOSITE.Enum(),
 						},
 					},
@@ -359,6 +359,44 @@ func TestRunFunction(t *testing.T) {
 				},
 			},
 		},
+		"ResponseIsReturnedWithTemplatingUsingTheTemplatesField": {
+			reason: "The Function should return the desired composite resource and the templated composed resources.",
+			args: args{
+				req: &fnv1.RunFunctionRequest{
+					Meta: &fnv1.RequestMeta{Tag: "templates"},
+					Input: resource.MustStructObject(
+						&v1beta1.GoTemplate{
+							Source: v1beta1.InlineSource,
+							Inline: &v1beta1.TemplateSourceInline{Templates: []string{cdTmpl}},
+						}),
+					Observed: &fnv1.State{
+						Composite: &fnv1.Resource{
+							Resource: resource.MustStructJSON(xr),
+						},
+					},
+					Desired: &fnv1.State{
+						Composite: &fnv1.Resource{
+							Resource: resource.MustStructJSON(xr),
+						},
+					},
+				},
+			},
+			want: want{
+				rsp: &fnv1.RunFunctionResponse{
+					Meta: &fnv1.ResponseMeta{Tag: "templates", Ttl: durationpb.New(response.DefaultTTL)},
+					Desired: &fnv1.State{
+						Composite: &fnv1.Resource{
+							Resource: resource.MustStructJSON(xr),
+						},
+						Resources: map[string]*fnv1.Resource{
+							"cool-cd": {
+								Resource: resource.MustStructJSON(`{"apiVersion": "example.org/v1","kind":"CD","metadata":{"annotations":{},"name":"cool-cd","labels":{"belongsTo":"cool-xr"}}}`),
+							},
+						},
+					},
+				},
+			},
+		},
 		"UpdateDesiredCompositeStatus": {
 			reason: "The Function should update the desired composite resource status.",
 			args: args{

input/v1beta1/input.go

@@ -49,9 +49,11 @@ const (
 	EnvironmentSource TemplateSource = "Environment"
 )
 
-// TemplateSourceInline defines the structure of the inline source.
+// TemplateSourceInline defines the structure of the inline source. Allows specifying either a single inline template or multiple templates, but not both.
+// +kubebuilder:validation:XValidation:rule="(has(self.template) ? 1 : 0) + (has(self.templates) ? 1 : 0) == 1",message="Exactly one of 'template' or 'templates' must be set"
 type TemplateSourceInline struct {
-	Template string `json:"template,omitempty"`
+	Template  string   `json:"template,omitempty"`
+	Templates []string `json:"templates,omitempty"`
 }
 
 // TemplateSourceFileSystem defines the structure of the filesystem source.

package/input/gotemplating.fn.crossplane.io_gotemplates.yaml

@@ -58,7 +58,15 @@ spec:
             properties:
               template:
                 type: string
+              templates:
+                items:
+                  type: string
+                type: array
             type: object
+            x-kubernetes-validations:
+            - message: Exactly one of 'template' or 'templates' must be set
+              rule: '(has(self.template) ? 1 : 0) + (has(self.templates) ? 1 : 0)
+                == 1'
           kind:
             description: |-
               Kind is a string value representing the REST resource this object represents.

template.go

@@ -3,6 +3,7 @@ package main
 import (
 	"io/fs"
 	"path/filepath"
+	"strings"
 
 	"github.com/crossplane-contrib/function-go-templating/input/v1beta1"
 	"google.golang.org/protobuf/types/known/structpb"
@@ -57,12 +58,18 @@ func (is *InlineSource) GetTemplates() string {
 }
 
 func newInlineSource(in *v1beta1.GoTemplate) (*InlineSource, error) {
-	if in.Inline == nil || in.Inline.Template == "" {
-		return nil, errors.New("inline.template should be provided")
+	if in.Inline == nil || (in.Inline.Template == "" && len(in.Inline.Templates) == 0) {
+		return nil, errors.New("inline.template or inline.templates should be provided")
+	}
+
+	template := strings.Join(in.Inline.Templates, "\n---\n")
+
+	if in.Inline.Template != "" {
+		template = in.Inline.Template
 	}
 
 	return &InlineSource{
-		Template: in.Inline.Template,
+		Template: template,
 	}, nil
 }