Add support for getting array index in GetValue

pkg/data/values.go

@@ -1,5 +1,15 @@
+// Package data contains functions for working with unstructured values like []interface or map[string]interface{}.
+// It allows reading/writing to these values without having to convert to structured items.
 package data
 
+import (
+	"strconv"
+)
+
+// RemoveValue removes a value from data. Keys should be in order denoting the path to the value in the nested
+// structure of the map. For example, passing []string{"metadata", "annotations"} will make the function remove the
+// "annotations" key from the "metadata" sub-map. Returns the removed value (if any) and a bool indicating if the value
+// was found.
 func RemoveValue(data map[string]interface{}, keys ...string) (interface{}, bool) {
 	for i, key := range keys {
 		if i == len(keys)-1 {
@@ -18,18 +28,45 @@ func GetValueN(data map[string]interface{}, keys ...string) interface{} {
 	return val
 }
 
-func GetValue(data map[string]interface{}, keys ...string) (interface{}, bool) {
+// GetValue retrieves a value from the provided collection, which must be a map[string]interface or a []interface.
+// Keys are always strings.
+// For a map, a key denotes the key in the map whose value we want to retrieve.
+// For the slice, it denotes the index (starting at 0) of the value we want to retrieve.
+// Returns the retrieved value (if any) and a bool indicating if the value was found.
+func GetValue(data interface{}, keys ...string) (interface{}, bool) {
 	for i, key := range keys {
 		if i == len(keys)-1 {
-			val, ok := data[key]
-			return val, ok
+			if dataMap, ok := data.(map[string]interface{}); ok {
+				val, ok := dataMap[key]
+				return val, ok
+			}
+			if dataSlice, ok := data.([]interface{}); ok {
+				return itemByIndex(dataSlice, key)
+			}
+		}
+		if dataMap, ok := data.(map[string]interface{}); ok {
+			data, _ = dataMap[key]
+		} else if dataSlice, ok := data.([]interface{}); ok {
+			data, _ = itemByIndex(dataSlice, key)
 		}
-		data, _ = data[key].(map[string]interface{})
 	}
 
 	return nil, false
 }
 
+func itemByIndex(dataSlice []interface{}, key string) (interface{}, bool) {
+	keyInt, err := strconv.Atoi(key)
+	if err != nil {
+		return nil, false
+	}
+	if keyInt >= len(dataSlice) || keyInt < 0 {
+		return nil, false
+	}
+	return dataSlice[keyInt], true
+}
+
+// PutValue updates the value of a given map at the index specified by keys that denote the path to the value in the
+// nested structure of the map. If there is no current entry at a key, a new map is created for that value.
 func PutValue(data map[string]interface{}, val interface{}, keys ...string) {
 	if data == nil {
 		return

pkg/data/values_test.go

@@ -0,0 +1,224 @@
+package data
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestGetValue(t *testing.T) {
+	t.Parallel()
+	tests := []struct {
+		name        string
+		data        interface{}
+		keys        []string
+		wantValue   interface{}
+		wantSuccess bool
+	}{
+		{
+			name:        "nil map",
+			data:        nil,
+			keys:        []string{"somekey"},
+			wantValue:   nil,
+			wantSuccess: false,
+		},
+		{
+			name: "key is not in map",
+			data: map[string]interface{}{
+				"realKey": "realVal",
+			},
+			keys:        []string{"badKey"},
+			wantValue:   nil,
+			wantSuccess: false,
+		},
+		{
+			name: "key is in first level of map",
+			data: map[string]interface{}{
+				"realKey": "realVal",
+			},
+			keys:        []string{"realKey"},
+			wantValue:   "realVal",
+			wantSuccess: true,
+		},
+		{
+			name: "key is nested in map",
+			data: map[string]interface{}{
+				"parent": map[string]interface{}{
+					"child": map[string]interface{}{
+						"grandchild": "someValue",
+					},
+				},
+			},
+			keys:        []string{"parent", "child", "grandchild"},
+			wantValue:   "someValue",
+			wantSuccess: true,
+		},
+		{
+			name: "incorrected nested key",
+			data: map[string]interface{}{
+				"parent": map[string]interface{}{
+					"child": map[string]interface{}{
+						"grandchild": "someValue",
+					},
+				},
+			},
+			keys:        []string{"parent", "grandchild", "child"},
+			wantValue:   nil,
+			wantSuccess: false,
+		},
+		{
+			name: "get index of slice",
+			data: map[string]interface{}{
+				"parent": map[string]interface{}{
+					"children": []interface{}{
+						"alice",
+						"bob",
+						"eve",
+					},
+				},
+			},
+			keys:        []string{"parent", "children", "2"},
+			wantValue:   "eve",
+			wantSuccess: true,
+		},
+		{
+			name: "get index of top level slice",
+			data: []interface{}{
+				"alice",
+				"bob",
+				"eve",
+			},
+			keys:        []string{"2"},
+			wantValue:   "eve",
+			wantSuccess: true,
+		},
+		{
+			name: "slice of maps",
+			data: []interface{}{
+				map[string]interface{}{
+					"notthisone": "val",
+				},
+				map[string]interface{}{
+					"parent": map[string]interface{}{
+						"children": []interface{}{
+							"alice",
+							"bob",
+							"eve",
+						},
+					},
+				},
+			},
+			keys:        []string{"1", "parent", "children", "0"},
+			wantValue:   "alice",
+			wantSuccess: true,
+		},
+		{
+			name: "index is too big",
+			data: map[string]interface{}{
+				"parent": map[string]interface{}{
+					"children": []interface{}{
+						"alice",
+						"bob",
+						"eve",
+					},
+				},
+			},
+			keys:        []string{"parent", "children", "3"},
+			wantValue:   nil,
+			wantSuccess: false,
+		},
+		{
+			name: "index is negative",
+			data: map[string]interface{}{
+				"parent": map[string]interface{}{
+					"children": []interface{}{
+						"alice",
+						"bob",
+						"eve",
+					},
+				},
+			},
+			keys:        []string{"parent", "children", "-3"},
+			wantValue:   nil,
+			wantSuccess: false,
+		},
+		{
+			name: "index not parseable to int",
+			data: map[string]interface{}{
+				"parent": map[string]interface{}{
+					"children": []interface{}{
+						"alice",
+						"bob",
+						"eve",
+					},
+				},
+			},
+			keys:        []string{"parent", "children", "notanint"},
+			wantValue:   nil,
+			wantSuccess: false,
+		},
+		{
+			name: "slice blank index",
+			data: []interface{}{
+				"bob",
+			},
+			keys:        []string{""},
+			wantValue:   nil,
+			wantSuccess: false,
+		},
+		{
+			name: "slice no index",
+			data: []interface{}{
+				"bob",
+			},
+			wantValue:   nil,
+			wantSuccess: false,
+		},
+		{
+			name: "keys nested too far",
+			data: []interface{}{
+				"alice",
+				"bob",
+				"eve",
+			},
+			keys:        []string{"2", "1"},
+			wantValue:   nil,
+			wantSuccess: false,
+		},
+		{
+			name: "map blank key with value",
+			data: map[string]interface{}{
+				"": "bob",
+			},
+			keys:        []string{""},
+			wantValue:   "bob",
+			wantSuccess: true,
+		},
+		{
+			name: "map blank key no value",
+			data: map[string]interface{}{
+				"alice": "bob",
+			},
+			keys:        []string{""},
+			wantValue:   nil,
+			wantSuccess: false,
+		},
+		{
+			name: "map no key",
+			data: map[string]interface{}{
+				"": "bob",
+			},
+			wantValue:   nil,
+			wantSuccess: false,
+		},
+	}
+	for _, test := range tests {
+		test := test
+		t.Run(test.name, func(t *testing.T) {
+			t.Parallel()
+			gotValue, gotSuccess := GetValue(test.data, test.keys...)
+			assert.Equal(t, test.wantValue, gotValue)
+			assert.Equal(t, test.wantSuccess, gotSuccess)
+		})
+	}
+}