feat: courier templates fs support

courier/template/load_template.go

@@ -5,8 +5,7 @@ import (
 	"embed"
 	htemplate "html/template"
 	"io"
-	"os"
-	"path"
+	"io/fs"
 	"path/filepath"
 	"text/template"
 
@@ -24,16 +23,16 @@ type Template interface {
 	Execute(wr io.Writer, data interface{}) error
 }
 
-func loadBuiltInTemplate(osdir, name string, html bool) (Template, error) {
+func loadBuiltInTemplate(filesytem fs.FS, name string, html bool) (Template, error) {
 	if t, found := cache.Get(name); found {
 		return t.(Template), nil
 	}
 
-	file, err := os.DirFS(osdir).Open(name)
+	file, err := filesytem.Open(name)
 	if err != nil {
 		// try to fallback to bundled templates
 		var fallbackErr error
-		file, fallbackErr = templates.Open(path.Join("courier/builtin/templates", name))
+		file, fallbackErr = templates.Open(filepath.Join("courier/builtin/templates", name))
 		if fallbackErr != nil {
 			// return original error from os.DirFS
 			return nil, errors.WithStack(err)
@@ -66,35 +65,37 @@ func loadBuiltInTemplate(osdir, name string, html bool) (Template, error) {
 	return tpl, nil
 }
 
-func loadTemplate(osdir, name, pattern string, html bool) (Template, error) {
+func loadTemplate(filesystem fs.FS, name, pattern string, html bool) (Template, error) {
 	if t, found := cache.Get(name); found {
 		return t.(Template), nil
 	}
 
-	// make sure osdir and template name exists, otherwise fallback to built in templates
-	f, _ := filepath.Glob(path.Join(osdir, name))
-	if f == nil {
-		return loadBuiltInTemplate(osdir, name, html)
+	matches, _ := fs.Glob(filesystem, name)
+	// make sure the file exists in the fs, otherwise fallback to built in templates
+	if matches == nil {
+		return loadBuiltInTemplate(filesystem, name, html)
 	}
 
-	// if pattern is defined, use it for glob
-	var glob string = name
+	glob := name
 	if pattern != "" {
-		m, _ := filepath.Glob(path.Join(osdir, pattern))
-		if m != nil {
+		// pattern matching is used when we have more than one gotmpl for different use cases, such as i18n support
+		// e.g. some_template/template_name* will match some_template/template_name.body.en_US.gotmpl
+		matches, _ = fs.Glob(filesystem, pattern)
+		// set the glob string to match patterns
+		if matches != nil {
 			glob = pattern
 		}
 	}
 
 	var tpl Template
 	if html {
-		t, err := htemplate.New(filepath.Base(name)).Funcs(sprig.HtmlFuncMap()).ParseGlob(path.Join(osdir, glob))
+		t, err := htemplate.New(filepath.Base(name)).Funcs(sprig.HtmlFuncMap()).ParseFS(filesystem, glob)
 		if err != nil {
 			return nil, errors.WithStack(err)
 		}
 		tpl = t
 	} else {
-		t, err := template.New(filepath.Base(name)).Funcs(sprig.TxtFuncMap()).ParseGlob(path.Join(osdir, glob))
+		t, err := template.New(filepath.Base(name)).Funcs(sprig.TxtFuncMap()).ParseFS(filesystem, glob)
 		if err != nil {
 			return nil, errors.WithStack(err)
 		}
@@ -105,23 +106,27 @@ func loadTemplate(osdir, name, pattern string, html bool) (Template, error) {
 	return tpl, nil
 }
 
-func LoadTextTemplate(osdir, name, pattern string, model interface{}) (string, error) {
-	t, err := loadTemplate(osdir, name, pattern, false)
+func LoadTextTemplate(filesystem fs.FS, name, pattern string, model interface{}) (string, error) {
+	t, err := loadTemplate(filesystem, name, pattern, false)
+
 	if err != nil {
 		return "", err
 	}
+
 	var b bytes.Buffer
 	if err := t.Execute(&b, model); err != nil {
 		return "", err
 	}
 	return b.String(), nil
 }
 
-func LoadHTMLTemplate(osdir, name, pattern string, model interface{}) (string, error) {
-	t, err := loadTemplate(osdir, name, pattern, true)
+func LoadHTMLTemplate(filesystem fs.FS, name, pattern string, model interface{}) (string, error) {
+	t, err := loadTemplate(filesystem, name, pattern, true)
+
 	if err != nil {
 		return "", err
 	}
+
 	var b bytes.Buffer
 	if err := t.Execute(&b, model); err != nil {
 		return "", err

courier/template/load_template_test.go

@@ -14,13 +14,13 @@ import (
 
 func TestLoadTextTemplate(t *testing.T) {
 	var executeTextTemplate = func(t *testing.T, dir, name, pattern string, model map[string]interface{}) string {
-		tp, err := LoadTextTemplate(dir, name, pattern, model)
+		tp, err := LoadTextTemplate(os.DirFS(dir), name, pattern, model)
 		require.NoError(t, err)
 		return tp
 	}
 
 	var executeHTMLTemplate = func(t *testing.T, dir, name, pattern string, model map[string]interface{}) string {
-		tp, err := LoadHTMLTemplate(dir, name, pattern, model)
+		tp, err := LoadHTMLTemplate(os.DirFS(dir), name, pattern, model)
 		require.NoError(t, err)
 		return tp
 	}

courier/template/recovery_invalid.go

@@ -2,6 +2,7 @@ package template
 
 import (
 	"encoding/json"
+	"os"
 )
 
 type (
@@ -23,15 +24,15 @@ func (t *RecoveryInvalid) EmailRecipient() (string, error) {
 }
 
 func (t *RecoveryInvalid) EmailSubject() (string, error) {
-	return LoadTextTemplate(t.c.CourierTemplatesRoot(), "recovery/invalid/email.subject.gotmpl", "recovery/invalid/email.subject*", t.m)
+	return LoadTextTemplate(os.DirFS(t.c.CourierTemplatesRoot()), "recovery/invalid/email.subject.gotmpl", "recovery/invalid/email.subject*", t.m)
 }
 
 func (t *RecoveryInvalid) EmailBody() (string, error) {
-	return LoadHTMLTemplate(t.c.CourierTemplatesRoot(), "recovery/invalid/email.body.gotmpl", "recovery/invalid/email.body*", t.m)
+	return LoadHTMLTemplate(os.DirFS(t.c.CourierTemplatesRoot()), "recovery/invalid/email.body.gotmpl", "recovery/invalid/email.body*", t.m)
 }
 
 func (t *RecoveryInvalid) EmailBodyPlaintext() (string, error) {
-	return LoadTextTemplate(t.c.CourierTemplatesRoot(), "recovery/invalid/email.body.plaintext.gotmpl", "recovery/invalid/email.body.plaintext*", t.m)
+	return LoadTextTemplate(os.DirFS(t.c.CourierTemplatesRoot()), "recovery/invalid/email.body.plaintext.gotmpl", "recovery/invalid/email.body.plaintext*", t.m)
 }
 
 func (t *RecoveryInvalid) MarshalJSON() ([]byte, error) {

courier/template/recovery_valid.go

@@ -2,6 +2,7 @@ package template
 
 import (
 	"encoding/json"
+	"os"
 )
 
 type (
@@ -25,15 +26,15 @@ func (t *RecoveryValid) EmailRecipient() (string, error) {
 }
 
 func (t *RecoveryValid) EmailSubject() (string, error) {
-	return LoadTextTemplate(t.c.CourierTemplatesRoot(), "recovery/valid/email.subject.gotmpl", "recovery/valid/email.subject*", t.m)
+	return LoadTextTemplate(os.DirFS(t.c.CourierTemplatesRoot()), "recovery/valid/email.subject.gotmpl", "recovery/valid/email.subject*", t.m)
 }
 
 func (t *RecoveryValid) EmailBody() (string, error) {
-	return LoadHTMLTemplate(t.c.CourierTemplatesRoot(), "recovery/valid/email.body.gotmpl", "recovery/valid/email.body*", t.m)
+	return LoadHTMLTemplate(os.DirFS(t.c.CourierTemplatesRoot()), "recovery/valid/email.body.gotmpl", "recovery/valid/email.body*", t.m)
 }
 
 func (t *RecoveryValid) EmailBodyPlaintext() (string, error) {
-	return LoadTextTemplate(t.c.CourierTemplatesRoot(), "recovery/valid/email.body.plaintext.gotmpl", "recovery/valid/email.body.plaintext*", t.m)
+	return LoadTextTemplate(os.DirFS(t.c.CourierTemplatesRoot()), "recovery/valid/email.body.plaintext.gotmpl", "recovery/valid/email.body.plaintext*", t.m)
 }
 
 func (t *RecoveryValid) MarshalJSON() ([]byte, error) {

courier/template/stub.go

@@ -2,6 +2,7 @@ package template
 
 import (
 	"encoding/json"
+	"os"
 )
 
 type TestStub struct {
@@ -24,15 +25,15 @@ func (t *TestStub) EmailRecipient() (string, error) {
 }
 
 func (t *TestStub) EmailSubject() (string, error) {
-	return LoadTextTemplate(t.c.CourierTemplatesRoot(), "test_stub/email.subject.gotmpl", "test_stub/email.subject*", t.m)
+	return LoadTextTemplate(os.DirFS(t.c.CourierTemplatesRoot()), "test_stub/email.subject.gotmpl", "test_stub/email.subject*", t.m)
 }
 
 func (t *TestStub) EmailBody() (string, error) {
-	return LoadHTMLTemplate(t.c.CourierTemplatesRoot(), "test_stub/email.body.gotmpl", "test_stub/email.body*", t.m)
+	return LoadHTMLTemplate(os.DirFS(t.c.CourierTemplatesRoot()), "test_stub/email.body.gotmpl", "test_stub/email.body*", t.m)
 }
 
 func (t *TestStub) EmailBodyPlaintext() (string, error) {
-	return LoadTextTemplate(t.c.CourierTemplatesRoot(), "test_stub/email.body.plaintext.gotmpl", "test_stub/email.body.plaintext*", t.m)
+	return LoadTextTemplate(os.DirFS(t.c.CourierTemplatesRoot()), "test_stub/email.body.plaintext.gotmpl", "test_stub/email.body.plaintext*", t.m)
 }
 
 func (t *TestStub) MarshalJSON() ([]byte, error) {

courier/template/verification_invalid.go

@@ -2,6 +2,7 @@ package template
 
 import (
 	"encoding/json"
+	"os"
 )
 
 type (
@@ -23,15 +24,15 @@ func (t *VerificationInvalid) EmailRecipient() (string, error) {
 }
 
 func (t *VerificationInvalid) EmailSubject() (string, error) {
-	return LoadTextTemplate(t.c.CourierTemplatesRoot(), "verification/invalid/email.subject.gotmpl", "verification/invalid/email.subject*", t.m)
+	return LoadTextTemplate(os.DirFS(t.c.CourierTemplatesRoot()), "verification/invalid/email.subject.gotmpl", "verification/invalid/email.subject*", t.m)
 }
 
 func (t *VerificationInvalid) EmailBody() (string, error) {
-	return LoadHTMLTemplate(t.c.CourierTemplatesRoot(), "verification/invalid/email.body.gotmpl", "verification/invalid/email.body*", t.m)
+	return LoadHTMLTemplate(os.DirFS(t.c.CourierTemplatesRoot()), "verification/invalid/email.body.gotmpl", "verification/invalid/email.body*", t.m)
 }
 
 func (t *VerificationInvalid) EmailBodyPlaintext() (string, error) {
-	return LoadTextTemplate(t.c.CourierTemplatesRoot(), "verification/invalid/email.body.plaintext.gotmpl", "verification/invalid/email.body.plaintext*", t.m)
+	return LoadTextTemplate(os.DirFS(t.c.CourierTemplatesRoot()), "verification/invalid/email.body.plaintext.gotmpl", "verification/invalid/email.body.plaintext*", t.m)
 }
 
 func (t *VerificationInvalid) MarshalJSON() ([]byte, error) {

courier/template/verification_valid.go

@@ -2,6 +2,7 @@ package template
 
 import (
 	"encoding/json"
+	"os"
 )
 
 type (
@@ -25,15 +26,15 @@ func (t *VerificationValid) EmailRecipient() (string, error) {
 }
 
 func (t *VerificationValid) EmailSubject() (string, error) {
-	return LoadTextTemplate(t.c.CourierTemplatesRoot(), "verification/valid/email.subject.gotmpl", "verification/valid/email.subject*", t.m)
+	return LoadTextTemplate(os.DirFS(t.c.CourierTemplatesRoot()), "verification/valid/email.subject.gotmpl", "verification/valid/email.subject*", t.m)
 }
 
 func (t *VerificationValid) EmailBody() (string, error) {
-	return LoadHTMLTemplate(t.c.CourierTemplatesRoot(), "verification/valid/email.body.gotmpl", "verification/valid/email.body*", t.m)
+	return LoadHTMLTemplate(os.DirFS(t.c.CourierTemplatesRoot()), "verification/valid/email.body.gotmpl", "verification/valid/email.body*", t.m)
 }
 
 func (t *VerificationValid) EmailBodyPlaintext() (string, error) {
-	return LoadTextTemplate(t.c.CourierTemplatesRoot(), "verification/valid/email.body.plaintext.gotmpl", "verification/valid/email.body.plaintext*", t.m)
+	return LoadTextTemplate(os.DirFS(t.c.CourierTemplatesRoot()), "verification/valid/email.body.plaintext.gotmpl", "verification/valid/email.body.plaintext*", t.m)
 }
 
 func (t *VerificationValid) MarshalJSON() ([]byte, error) {