template: add filter to get map value by key

HeavyHorst · Jun 29, 2020 · e36da5f · e36da5f
1 parent 04c1d6c
commit e36da5f
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diff --git a/docs/content/template/template-filters.md b/docs/content/template/template-filters.md
@@ -39,6 +39,13 @@ weight: 20
 ```
 </details>
 
+<details>
+<summary> **mapValue** -- Returns an map element by key  </summary>
+```
+{{ getv("/some_yaml_config") | parseYAML | mapValue:"key" }}
+```
+</details>
+
 <details>
 <summary> **index** -- Returns an array element by index  </summary>
 ```

diff --git a/pkg/template/template_filters.go b/pkg/template/template_filters.go
@@ -14,6 +14,7 @@ import (
 	"io/ioutil"
 	"path"
 	"path/filepath"
+	"reflect"
 	"sort"
 	"strings"
 
@@ -36,6 +37,7 @@ func init() {
 	pongo2.RegisterFilter("base", filterBase)
 	pongo2.RegisterFilter("base64", filterBase64)
 	pongo2.RegisterFilter("index", filterIndex)
+	pongo2.RegisterFilter("mapValue", filterMapValue)
 }
 
 // RegisterCustomJsFilters loads all filters from the given directory.
@@ -167,6 +169,30 @@ func filterIndex(in *pongo2.Value, param *pongo2.Value) (*pongo2.Value, *pongo2.
 	return pongo2.AsValue(in.Index(index)), nil
 }
 
+func filterMapValue(in *pongo2.Value, param *pongo2.Value) (*pongo2.Value, *pongo2.Error) {
+	if in == nil || in.IsNil() {
+		return pongo2.AsValue(nil), nil
+	}
+
+	val := reflect.ValueOf(in.Interface())
+	if val.Kind() == reflect.Map {
+		valueType := val.Type().Key().Kind()
+		paramValue := reflect.ValueOf(param.Interface())
+
+		if paramValue.Kind() != valueType {
+			return pongo2.AsValue(nil), nil
+		}
+
+		mv := val.MapIndex(paramValue)
+		if !mv.IsValid() {
+			return pongo2.AsValue(nil), nil
+		}
+
+		return pongo2.AsValue(mv.Interface()), nil
+	}
+	return pongo2.AsValue(nil), nil
+}
+
 func filterSortByLength(in *pongo2.Value, param *pongo2.Value) (*pongo2.Value, *pongo2.Error) {
 	if !in.CanSlice() {
 		return in, nil

diff --git a/pkg/template/template_filters_test.go b/pkg/template/template_filters_test.go
@@ -156,6 +156,48 @@ func (s *FilterSuite) TestFilterSortByLengthKVPair(t *C) {
 	t.Check(m1, DeepEquals, expected)
 }
 
+func (s *FilterSuite) TestFilterMapValue(t *C) {
+	a := map[string]int{
+		"hallo": 1,
+		"moin":  2,
+	}
+	fm, err := filterMapValue(pongo2.AsValue(a), pongo2.AsValue("moin"))
+	if err != nil {
+		t.Error(err.OrigError)
+	}
+	t.Check(fm.Interface(), DeepEquals, 2)
+
+	b := map[string]string{
+		"servus": "one",
+		"hi":     "oneone",
+	}
+	fm, err = filterMapValue(pongo2.AsValue(b), pongo2.AsValue("servus"))
+	if err != nil {
+		t.Error(err.OrigError)
+	}
+	t.Check(fm.Interface(), DeepEquals, "one")
+
+	c := map[string]interface{}{
+		"servus": "one",
+		"hi":     100,
+	}
+	fm, err = filterMapValue(pongo2.AsValue(c), pongo2.AsValue("hi"))
+	if err != nil {
+		t.Error(err.OrigError)
+	}
+	t.Check(fm.Interface(), DeepEquals, 100)
+
+	d := map[int]string{
+		1: "one",
+		2: "oneone",
+	}
+	fm, err = filterMapValue(pongo2.AsValue(d), pongo2.AsValue(2))
+	if err != nil {
+		t.Error(err.OrigError)
+	}
+	t.Check(fm.Interface(), DeepEquals, "oneone")
+}
+
 func (s *FilterSuite) TestFilterIndex(t *C) {
 	in := pongo2.AsValue([]string{"Hallo", "Test", "123", "Moin"})
 	expected := "123"