Access and change env variables in the config

Author: Priya Wadhwa

pkg/image/mutable_source.go

@@ -22,6 +22,7 @@ import (
 	"encoding/json"
 	"io"
 	"io/ioutil"
+	"strings"
 	"time"
 
 	"github.com/containers/image/manifest"
@@ -166,3 +167,26 @@ func (m *MutableSource) saveConfig() error {
 	}
 	return nil
 }
+
+// Env returns a map of environment variables stored in the image config
+// Converts each variable from a string of the form KEY=VALUE to a map of KEY:VALUE
+func (m *MutableSource) Env() map[string]string {
+	envArray := m.cfg.Schema2V1Image.Config.Env
+	envMap := make(map[string]string)
+	for _, env := range envArray {
+		entry := strings.Split(env, "=")
+		envMap[entry[0]] = entry[1]
+	}
+	return envMap
+}
+
+// SetEnv takes a map of environment variables, and converts them to an array of strings
+// in the form KEY=VALUE, and then sets the image config
+func (m *MutableSource) SetEnv(envMap map[string]string) {
+	envArray := []string{}
+	for key, value := range envMap {
+		entry := key + "=" + value
+		envArray = append(envArray, entry)
+	}
+	m.cfg.Schema2V1Image.Config.Env = envArray
+}

pkg/image/mutable_source_test.go

@@ -19,6 +19,7 @@ package image
 import (
 	"encoding/json"
 	"io/ioutil"
+	"reflect"
 	"testing"
 
 	"github.com/containers/image/manifest"
@@ -115,3 +116,42 @@ func TestMutableSource_AppendLayer(t *testing.T) {
 		})
 	}
 }
+
+func TestMutableSource_Env(t *testing.T) {
+
+	cfg := &manifest.Schema2Image{
+		Schema2V1Image: manifest.Schema2V1Image{
+			Config: &manifest.Schema2Config{
+				Env: []string{
+					"PATH=/path/to/dir",
+				},
+			},
+		},
+	}
+
+	m := &MutableSource{
+		mfst:       &manifest.Schema2{},
+		cfg:        cfg,
+		extraBlobs: make(map[string][]byte),
+	}
+	initialEnvMap := m.Env()
+	expectedInitialEnvMap := map[string]string{
+		"PATH": "/path/to/dir",
+	}
+	if !reflect.DeepEqual(initialEnvMap, expectedInitialEnvMap) {
+		t.Fatalf("Got incorrect environment map, got: %s, expected: %s", initialEnvMap, expectedInitialEnvMap)
+	}
+
+	initialEnvMap["NEW"] = "new"
+
+	m.SetEnv(initialEnvMap)
+
+	newEnvMap := m.Env()
+	expectedNewEnvMap := map[string]string{
+		"PATH": "/path/to/dir",
+		"NEW":  "new",
+	}
+	if !reflect.DeepEqual(newEnvMap, expectedNewEnvMap) {
+		t.Fatalf("Got incorrect environment map, got: %s, expected: %s", newEnvMap, expectedNewEnvMap)
+	}
+}