chore: support include

core/fs.go

@@ -0,0 +1,12 @@
+package wharf
+
+import "os"
+
+// IsDirectory checks if the given path is a directory
+func isDirectory(path string) (bool, error) {
+	info, err := os.Stat(path)
+	if err != nil {
+		return false, err
+	}
+	return info.IsDir(), nil
+}

core/function_factory.go

@@ -0,0 +1,82 @@
+package wharf
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+
+	types "github.com/Makepad-fr/wharf/types"
+)
+
+// newFunctionFactory creates a new function factory witht the given context path
+func newFunctionFactory(contextPath string) functionFactory {
+	return functionFactory{
+		contextPath: contextPath,
+	}
+}
+
+// functionFactory crates a context aware functionMap for each template.
+type functionFactory struct {
+	contextPath string // THe path of the current template file that executes this function map
+}
+
+// Include includdes returns the content of as string. The [path] should either be
+// a Dockerfile or a Dockerfile.template. If it's a Dockefile.template the [values] will
+// be used to render the template using wharf. If it's a Dockerfile the cotnent will be rendered as it's.
+// If any erorr happens it will returned as an error string as template function can not return errors as Go objects.
+// FIXME: Users may use other filenames other then Dockerfile and Dockerifle.template especially when they are using from the same folder
+func (f functionFactory) Include(path string, values types.ValueMap) string {
+	// Update the passed path with the context path
+	path = filepath.Join(f.contextPath, path)
+	isDir, err := isDirectory(path)
+
+	if err != nil {
+		return fmt.Sprintf("Error while importing %s: %s", path, err.Error())
+	}
+	// Create a generic error message template
+	const errorMessage = "Error: Include should be called either with a Dockerfile.template path or with a Dockerfile path"
+	if isDir {
+		return errorMessage
+	} else {
+		baseFileName := filepath.Base(path)
+		if baseFileName == "Dockerfile" {
+			// If the path is a Dockerfile path
+			file, err := os.Open(path)
+			if err != nil {
+				return fmt.Sprintf("Error: error while opening Dockerfile from %s", path)
+			}
+			content, err := io.ReadAll(file)
+			if err != nil {
+				return fmt.Sprintf("Error: error while reading file content %s", err.Error())
+			}
+			return string(content)
+		}
+		if baseFileName == "Dockerfile.template" {
+			// IF the path is a Dockerfile.template
+			contextPath := filepath.Dir(path)
+			// Don't use include in included templates as it creates a cyclic dependency
+			// TODO: Maybe we can copy the funcMap before using it?
+			template, err := getTemplate(contextPath, baseFileName, map[string]any{})
+			if err != nil {
+				return fmt.Sprintf("Error: error while getting template from %s: %s", path, err.Error())
+			}
+			var renderedContent bytes.Buffer
+			err = render(template, values, &renderedContent)
+			if err != nil {
+				return fmt.Sprintf("Error: error while rendering template %s: %s", path, err.Error())
+			}
+			return renderedContent.String()
+		}
+		return errorMessage
+	}
+}
+
+// Creates the types.FuncMap for the related function factory
+// FIXME: Check if it's possible to create this function map programmatically
+func (f functionFactory) FuncMap() types.FuncMap {
+	return map[string]any{
+		"include": f.Include,
+	}
+}

core/render.go

@@ -13,7 +13,9 @@ import (
 // Render renders the template file in the given contextPath using the values files from the given path
 // It writes the rendered Dockerfile to the io.Writer passed in parameters. It returns an error if something goes wrong
 func Render(contextPath, templateFileName, valuesFilePath string, output io.Writer) error {
-	template, err := getTemplate(contextPath, templateFileName)
+	// Create a new function map
+	funcMap := newFunctionFactory(contextPath).FuncMap()
+	template, err := getTemplate(contextPath, templateFileName, funcMap)
 	if err != nil {
 		return err
 	}
@@ -23,12 +25,13 @@ func Render(contextPath, templateFileName, valuesFilePath string, output io.Writ
 	}
 
 	err = render(template, values, output)
-	return nil
+	return err
 }
 
 // render renders the template and values to the file with the given path.
 // If something goes wrong it returns an error
 func render(tmpl *template.Template, values map[string]any, file io.Writer) error {
+	// Include function map to the current template just before rendering the values
 	err := tmpl.Execute(file, values)
 	if err != nil {
 		return err
@@ -56,21 +59,20 @@ func readValues(contextPath, valuesFilePath string) (map[string]any, error) {
 }
 
 // getTemplate returns the template.Template from given context path and templatefile name
-func getTemplate(contextPath, templateFileName string) (*template.Template, error) {
+func getTemplate(contextPath, templateFileName string, funcMap template.FuncMap) (*template.Template, error) {
 	info, err := os.Stat(contextPath)
 	if err != nil {
 		return nil, err
 	}
 	if !info.IsDir() {
-		return nil, fmt.Errorf("Context path %s should be a directory path. To pass template file name use -file-name option", contextPath)
+		return nil, fmt.Errorf("context path %s should be a directory path. To pass template file name use -file-name option", contextPath)
 	}
 
 	contextPath = filepath.Join(contextPath, templateFileName)
 
-	templ, err := template.ParseFiles(contextPath)
+	templ, err := template.New(filepath.Base(templateFileName)).Funcs(funcMap).ParseFiles(contextPath)
 	if err != nil {
 		return nil, err
 	}
-
 	return templ, nil
 }

go.work

@@ -1,8 +1,9 @@
-go 1.22.2
+go 1.22.4
 
 use (
 	./cli
 	./core
 	./docker-cli-plugins/commons
 	./docker-cli-plugins/render
+	./types
 )

types/go.mod

@@ -0,0 +1,3 @@
+module github.com/Makepad-fr/wharf/types
+
+go 1.22.4

types/types.go

@@ -0,0 +1,9 @@
+package types
+
+import "text/template"
+
+// TODO: template.FuncMap uses map[string]any and any is a function with an arbitrary number of arguments func(args ....), we need to check if we can create a type for that
+type FuncMap = template.FuncMap
+
+// TODO: Change to more restrictive type as it will be used only for values
+type ValueMap = map[string]any