Add template functions for list/inspect message

Makes it possible to show all messages using a format string like:

    {{.Name}}{{"\n"}}{{.Message | missing "<no message>" | indent 2 | trim "\n"}}

In case you missed the message the first time, and want to show it.

This is instead of having a dedicated lima command like "message".

Signed-off-by: Anders F Björklund <[email protected]>

Author: afbjorklund

cmd/limactl/list.go

@@ -41,7 +41,8 @@ func newListCommand() *cobra.Command {
 		  --format yaml  - output in yaml format
 		  --format table - output in table format
 		  --format '{{ <go template> }}' - if the format begins and ends with '{{ }}', then it is used as a go template.
-
+` + store.FormatHelp +
+			`
 		The following legacy flags continue to function:
 		  --json - equal to '--format json'
 		`,

pkg/store/instance.go

@@ -211,6 +211,11 @@ type FormatData struct {
 	IdentityFile string
 }
 
+var FormatHelp = "\n" + textutil.PrefixString("\t\t",
+	"These functions are available to go templates:\n\n"+
+		textutil.IndentString(2,
+			strings.Join(textutil.FuncHelp, "\n")+"\n"))
+
 func AddGlobalFields(inst *Instance) (FormatData, error) {
 	var data FormatData
 	data.Instance = *inst

pkg/textutil/textutil.go

@@ -23,6 +23,37 @@ func ExecuteTemplate(tmpl string, args interface{}) ([]byte, error) {
 	return b.Bytes(), nil
 }
 
+// PrefixString adds prefix to beginning of each line
+func PrefixString(prefix string, text string) string {
+	result := ""
+	for _, line := range strings.Split(text, "\n") {
+		if line == "" {
+			continue
+		}
+		result += prefix + line + "\n"
+	}
+	return result
+}
+
+// IndentString add spaces to beginning of each line
+func IndentString(size int, text string) string {
+	prefix := strings.Repeat(" ", size)
+	return PrefixString(prefix, text)
+}
+
+// TrimString removes characters from beginning and end
+func TrimString(cutset string, text string) string {
+	return strings.Trim(text, cutset)
+}
+
+// MissingString returns message if the text is empty
+func MissingString(message string, text string) string {
+	if text == "" {
+		return message
+	}
+	return text
+}
+
 // TemplateFuncMap is a text/template FuncMap.
 var TemplateFuncMap = template.FuncMap{
 	"json": func(v interface{}) string {
@@ -42,4 +73,14 @@ var TemplateFuncMap = template.FuncMap{
 		}
 		return "---\n" + strings.TrimSuffix(b.String(), "\n")
 	},
+	"indent":  IndentString,
+	"trim":    TrimString,
+	"missing": MissingString,
+}
+
+// TemplateFuncHelp is help for TemplateFuncMap.
+var FuncHelp = []string{
+	"indent <size>: add spaces to beginning of each line",
+	"trim <cutset>: remove characters from beginning and end",
+	"missing <message>: return message if the text is empty",
 }

pkg/textutil/textutil_test.go

@@ -8,18 +8,43 @@ import (
 	"gotest.tools/v3/assert"
 )
 
+func TestPrefixString(t *testing.T) {
+	assert.Equal(t, "- foo\n", PrefixString("- ", "foo"))
+	assert.Equal(t, "- foo\n- bar\n", PrefixString("- ", "foo\nbar\n"))
+}
+func TestIndentString(t *testing.T) {
+	assert.Equal(t, "  foo\n", IndentString(2, "foo"))
+	assert.Equal(t, "  foo\n  bar\n", IndentString(2, "foo\nbar\n"))
+}
+
+func TestTrimString(t *testing.T) {
+	assert.Equal(t, "foo", TrimString("\n", "foo"))
+	assert.Equal(t, "bar", TrimString("\n", "bar\n"))
+}
+
+func TestMissingString(t *testing.T) {
+	assert.Equal(t, "no", MissingString("no", ""))
+	assert.Equal(t, "msg", MissingString("no", "msg"))
+}
+
 func TestTemplateFuncs(t *testing.T) {
 	type X struct {
-		Foo int    `json:"foo" yaml:"foo"`
-		Bar string `json:"bar" yaml:"bar"`
+		Foo     int    `json:"foo" yaml:"foo"`
+		Bar     string `json:"bar" yaml:"bar"`
+		Message string `json:"message,omitempty" yaml:"message,omitempty"`
 	}
-	x := X{Foo: 42, Bar: "hello"}
+	x := X{Foo: 42, Bar: "hello", Message: "One\nTwo\nThree\n"}
 
 	testCases := map[string]string{
-		"{{json .}}": `{"foo":42,"bar":"hello"}`,
+		"{{json .}}": `{"foo":42,"bar":"hello","message":"One\nTwo\nThree\n"}`,
 		"{{yaml .}}": `---
 foo: 42
-bar: hello`,
+bar: hello
+message: |
+  One
+  Two
+  Three`,
+		`{{.Bar}}{{"\n"}}{{.Message | missing "<no message>" | indent 2 | trim "\n"}}`: "hello\n  One\n  Two\n  Three",
 	}
 
 	for format, expected := range testCases {