Add string functions for lowercase, uppercase and capitalize to shoutrrr templates (#593)

* Added string functions for lowercase, uppercase and capitalize to shoutrrr templates

* Update pkg/notifications/shoutrrr.go

Co-authored-by: nils måsén <nils@piksel.se>

* Update pkg/notifications/shoutrrr.go

Co-authored-by: nils måsén <nils@piksel.se>

* Update pkg/notifications/shoutrrr.go

Co-authored-by: nils måsén <nils@piksel.se>

* Update pkg/notifications/shoutrrr_test.go

Co-authored-by: nils måsén <nils@piksel.se>

* escape quotation marks in test

Co-authored-by: nils måsén <nils@piksel.se>

pkg/notifications/shoutrrr.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"fmt"
 	"text/template"
+    "strings"
 
 	"github.com/containrrr/shoutrrr"
 	"github.com/containrrr/shoutrrr/pkg/router"
@@ -109,10 +110,16 @@ func getShoutrrrTemplate(c *cobra.Command) *template.Template {
 
 	tplString, err := flags.GetString("notification-template")
 
+	funcs := template.FuncMap{
+		"ToUpper": strings.ToUpper,
+		"ToLower": strings.ToLower,
+		"Title": strings.Title,
+	}
+
 	// If we succeed in getting a non-empty template configuration
 	// try to parse the template string.
 	if tplString != "" && err == nil {
-		tpl, err = template.New("").Parse(tplString)
+		tpl, err = template.New("").Funcs(funcs).Parse(tplString)
 	}
 
 	// In case of errors (either from parsing the template string
@@ -128,7 +135,7 @@ func getShoutrrrTemplate(c *cobra.Command) *template.Template {
 	// template wasn't configured (the empty template string)
 	// fallback to using the default template.
 	if err != nil || tplString == "" {
-		tpl = template.Must(template.New("").Parse(shoutrrrDefaultTemplate))
+		tpl = template.Must(template.New("").Funcs(funcs).Parse(shoutrrrDefaultTemplate))
 	}
 
 	return tpl

pkg/notifications/shoutrrr_test.go

@@ -51,6 +51,30 @@ func TestShoutrrrTemplate(t *testing.T) {
 	require.Equal(t, "info: foo bar\n", s)
 }
 
+func TestShoutrrrStringFunctions(t *testing.T) {
+	cmd := new(cobra.Command)
+	flags.RegisterNotificationFlags(cmd)
+	err := cmd.ParseFlags([]string{"--notification-template={{range .}}{{.Level | printf \"%v\" | ToUpper }}: {{.Message | ToLower }} {{.Message | Title }}{{println}}{{end}}"})
+
+	require.NoError(t, err)
+
+	shoutrrr := &shoutrrrTypeNotifier{
+		template: getShoutrrrTemplate(cmd),
+	}
+
+	entries := []*log.Entry{
+		{
+			Level:   log.InfoLevel,
+			Message: "foo Bar",
+		},
+	}
+
+	s := shoutrrr.buildMessage(entries)
+
+	require.Equal(t, "INFO: foo bar Foo Bar\n", s)
+}
+
+
 func TestShoutrrrInvalidTemplateUsesTemplate(t *testing.T) {
 	cmd := new(cobra.Command)