add support for YAML format cnf/yaml + tests

internal/cnf/loader.go

@@ -71,6 +71,8 @@ func loadFromExtension(ext string) ConfigurationFormat {
 		return new(json)
 	case ".ini":
 		return new(ini)
+	case ".yaml":
+		return new(yaml)
 	case ".conf":
 		return new(confl)
 	default:

internal/cnf/yaml.go

@@ -0,0 +1,136 @@
+package cnf
+
+import (
+	lib "gopkg.in/yaml.v2"
+	"io"
+	"strings"
+)
+
+type yaml struct {
+	data   interface{}
+	parsed bool
+}
+
+// ReadFrom implements io.ReaderFrom
+func (d *yaml) ReadFrom(_reader io.Reader) (int64, error) {
+
+	// 1. get yaml decoder
+	decoder := lib.NewDecoder(_reader)
+	err := decoder.Decode(&d.data)
+	if err != nil {
+		return 0, err
+	}
+	d.parsed = true
+	return 0, nil
+
+}
+
+// WriteTo implements io.WriterTo
+func (d *yaml) WriteTo(_writer io.Writer) (int64, error) {
+	encoder := lib.NewEncoder(_writer)
+	defer encoder.Close()
+	return 0, encoder.Encode(&d.data)
+}
+
+// browse returns the target of a dot-separated path (as an interface{} chain where the last is the target if found)
+func (d *yaml) browse(_path string) ([]interface{}, bool) {
+
+	// 1. extract path
+	path := strings.Split(_path, ".")
+
+	// 2. init output chain
+	current := d.data
+	chain := make([]interface{}, 0, len(path)+1)
+	chain = append(chain, current)
+
+	// 3. iterate over path / nested fields
+	for _, field := range path {
+		fmap, ok := current.(map[interface{}]interface{})
+		if !ok { // incomplete path
+			return chain, false
+		}
+
+		child, ok := fmap[field]
+		if !ok { // incomplete path
+			return chain, false
+		}
+
+		current = child
+		chain = append(chain, current)
+	}
+
+	return chain, true
+}
+
+// Get returns the value of a dot-separated path, and if it exists
+func (d *yaml) Get(_path string) (string, bool) {
+
+	// 1. browse path
+	chain, found := d.browse(_path)
+	if !found {
+		return "", false
+	}
+
+	// 2. return if string value
+	value, ok := chain[len(chain)-1].(string)
+	return value, ok
+
+}
+
+// Set the value of a dot-separated path, and creates it if not found
+func (d *yaml) Set(_path, _value string) bool {
+
+	// 1. browse path + create it if does not exist
+	path := strings.Split(_path, ".")
+	lp := len(path)
+	chain, found := d.browse(_path)
+
+	// 2. if found -> set value
+	if found {
+		mapWrapper, ok := chain[len(chain)-2].(map[interface{}]interface{})
+		if !ok { // impossible
+			return false
+		}
+		key := path[lp-1]
+		mapWrapper[key] = _value
+		return true
+	}
+
+	// 3. create path until the end to set value
+	root := make(map[interface{}]interface{})
+	current := root
+
+	// create children until second to last
+	for i, l := len(chain)-1, lp-1; i < l; i++ {
+		child := make(map[interface{}]interface{})
+		current[path[i]] = child
+		current = child
+	}
+
+	// set value
+	current[path[lp-1]] = _value
+
+	// replace whole object if empty
+	if len(chain) < 2 {
+		wrapper, ok := d.data.(map[interface{}]interface{})
+		if !ok { // impossible
+			return false
+		}
+		key := path[0]
+		wrapper[key] = root[key] // store with key ; eitherway it will erase all brother keys
+		return true
+	}
+
+	// update last found object to add the value
+	wrapper, ok := chain[len(chain)-1].(map[interface{}]interface{})
+	if !ok { // impossible
+		return false
+	}
+
+	// add each subkey
+	for subkey, subvalue := range root {
+		wrapper[subkey] = subvalue
+	}
+	return true
+
+}

internal/cnf/yaml_test.go

@@ -0,0 +1,192 @@
+package cnf
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestYamlGet(t *testing.T) {
+
+	tests := []struct {
+		raw string
+		key string
+	}{
+		{"key: value\n", "key"},
+		{"ignore: xxx\nkey: value\n", "key"},
+		{"parent:\n  child: value\n", "parent.child"},
+		{"ignore: xxx\nparent:\n  child: value\n", "parent.child"},
+	}
+
+	for _, test := range tests {
+
+		parser := new(yaml)
+		reader := bytes.NewBufferString(test.raw)
+
+		// try to extract value
+		_, err := parser.ReadFrom(reader)
+		if err != nil {
+			t.Errorf("parse error: %s", err)
+			continue
+		}
+
+		// extract value
+		value, found := parser.Get(test.key)
+		if !found {
+			t.Errorf("expected a result, got none")
+			continue
+		}
+
+		// check value
+		if value != "value" {
+			t.Errorf("expected 'value' got '%s'", value)
+		}
+
+	}
+
+}
+
+func TestYamlGetNotString(t *testing.T) {
+
+	tests := []struct {
+		raw string
+		key string
+	}{
+		{"key:\n- value\n", "key"},
+		{"key:\n  subkey: value\n", "key"},
+		{"parent:\n  child:\n  - value\n", "parent.child"},
+		{"parent:\n  child:\n  subkey: value\n", "parent.child"},
+	}
+
+	for i, test := range tests {
+
+		parser := new(yaml)
+		reader := bytes.NewBufferString(test.raw)
+
+		// try to extract value
+		_, err := parser.ReadFrom(reader)
+		if err != nil {
+			t.Errorf("[%d] parse error: %s", i, err)
+			continue
+		}
+
+		// extract value
+		value, found := parser.Get(test.key)
+		if found || len(value) > 0 {
+			t.Errorf("[%d] expected no result, got '%s'", i, value)
+			continue
+		}
+
+	}
+
+}
+
+func TestYamlSetPathExistsAndIsString(t *testing.T) {
+
+	tests := []struct {
+		raw   string
+		key   string
+		value string
+	}{
+		{"key: value\n", "key", "newvalue"},
+		{"ignore: xxx\nkey: value\n", "key", "newvalue"},
+		{"parent:\n  child: value\n", "parent.child", "newvalue"},
+		{"ignore: xxx\nparent:\n  child: value\n", "parent.child", "newvalue"},
+	}
+
+	for i, test := range tests {
+
+		parser := new(yaml)
+		reader := bytes.NewBufferString(test.raw)
+
+		// try to extract value
+		_, err := parser.ReadFrom(reader)
+		if err != nil {
+			t.Errorf("parse error: %s", err)
+			continue
+		}
+
+		// update value
+		if !parser.Set(test.key, test.value) {
+			t.Errorf("[%d] cannot set '%s' to '%s'", i, test.key, test.value)
+			continue
+		}
+
+		// check new value
+		value, found := parser.Get(test.key)
+		if !found {
+			t.Errorf("[%d] expected a result, got none", i)
+			continue
+		}
+
+		// check value
+		if value != test.value {
+			t.Errorf("[%d] expected '%s' got '%s'", i, test.value, value)
+		}
+
+	}
+
+}
+
+func TestYamlSetCreatePath(t *testing.T) {
+
+	tests := []struct {
+		raw    string
+		key    string
+		ignore string // path to field that must be present after transformation
+		value  string
+	}{
+		{"ignore: xxx\n", "key", "ignore", "newvalue"},
+		{"ignore: xxx\n", "parent.child", "ignore", "newvalue"},
+		{"ignore: xxx\n", "parent.child.subchild", "ignore", "newvalue"},
+
+		{"ignore: xxx\n", "key", "ignore", "newvalue"},
+		{"parent:\n  ignore: xxx\n", "parent.child", "parent.ignore", "newvalue"},
+		{"ignore: xxx\nparent: {}\n", "parent.child", "ignore", "newvalue"},
+	}
+
+	for i, test := range tests {
+
+		parser := new(yaml)
+		reader := bytes.NewBufferString(test.raw)
+
+		// try to extract value
+		_, err := parser.ReadFrom(reader)
+		if err != nil {
+			t.Errorf("[%d] parse error: %s", i, err)
+			continue
+		}
+
+		// update value
+		if !parser.Set(test.key, test.value) {
+			t.Errorf("[%d] cannot set '%s' to '%s'", i, test.key, test.value)
+			continue
+		}
+
+		// check new value
+		value, found := parser.Get(test.key)
+		if !found {
+			t.Errorf("[%d] expected a result, got none", i)
+			continue
+		}
+
+		// check value
+		if value != test.value {
+			t.Errorf("[%d] expected '%s' got '%s'", i, test.value, value)
+			continue
+		}
+
+		// check that ignore field is still there
+		value, found = parser.Get(test.ignore)
+		if !found {
+			t.Errorf("[%d] expected ignore field, got none", i)
+			continue
+		}
+
+		// check value
+		if value != "xxx" {
+			t.Errorf("[%d] expected ignore value to be '%s' got '%s'", i, "xxx", value)
+			continue
+		}
+	}
+
+}