better handling of nested structs and add tests

Author: lucasreed

cmd/dependency/dependency.go

@@ -96,8 +96,10 @@ func InitCommandAndConfig(cmd *cobra.Command, useConfigFile bool, config any) {
 // bindEnvsFromConfig binds an env for every config key, so AutomaticEnv can
 // override keys that are not present in the config file.
 func bindEnvsFromConfig(config any) {
-	// Marshal the default config and let viper flatten it into keys.
-	b, err := yaml.Marshal(config)
+	schema := reflect.New(reflect.TypeOf(config).Elem()).Interface()
+	materializeStructPtrs(reflect.ValueOf(schema).Elem())
+
+	b, err := yaml.Marshal(schema)
 	if err != nil {
 		panic(fmt.Errorf("marshal config for env binding: %w", err))
 	}
@@ -113,6 +115,29 @@ func bindEnvsFromConfig(config any) {
 	}
 }
 
+// materializeStructPtrs allocates nil struct-pointers so their nested keys serialize.
+func materializeStructPtrs(v reflect.Value) {
+	switch v.Kind() {
+	case reflect.Pointer:
+		if v.Type().Elem().Kind() != reflect.Struct {
+			return
+		}
+		if v.IsNil() {
+			if !v.CanSet() {
+				return
+			}
+			v.Set(reflect.New(v.Type().Elem()))
+		}
+		materializeStructPtrs(v.Elem())
+	case reflect.Struct:
+		for i := 0; i < v.NumField(); i++ {
+			if f := v.Field(i); f.CanSet() {
+				materializeStructPtrs(f)
+			}
+		}
+	}
+}
+
 // InitMonitor initialize monitor and return final handler.
 func InitMonitor(ctx context.Context, pprofPort int, tracingConfig base.TracingConfig) func() {
 	var shutdowns = make(chan func(), 2)

cmd/dependency/dependency_test.go

@@ -0,0 +1,117 @@
+/*
+ *     Copyright 2020 The Dragonfly Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package dependency
+
+import (
+	"strings"
+	"testing"
+
+	"github.com/spf13/viper"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
+	schedulerconfig "d7y.io/dragonfly/v2/scheduler/config"
+)
+
+// tlsConfig mirrors the optional, pointer-typed TLS sections of the real
+// configs (e.g. scheduler/config.Config.Server.TLS), which are left nil by the
+// default config and therefore never appear in a marshalled value snapshot.
+type tlsConfig struct {
+	CACert string `yaml:"caCert" mapstructure:"caCert"`
+}
+
+// testConfig mirrors the real config shape: populated scalar defaults plus an
+// optional nested section behind a nil pointer.
+type testConfig struct {
+	Name string     `yaml:"name" mapstructure:"name"`
+	TLS  *tlsConfig `yaml:"tls" mapstructure:"tls"`
+}
+
+// newTestConfig returns the default config: scalar defaults set, optional TLS
+// section left nil (as config.New() does for the real configs).
+func newTestConfig() *testConfig {
+	return &testConfig{Name: "default-name"}
+}
+
+// setupViper resets and configures the package-global viper the same way
+// InitCommandAndConfig does, with the given env prefix.
+func setupViper(prefix string) {
+	viper.Reset()
+	viper.SetEnvPrefix(prefix)
+	viper.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
+	viper.AutomaticEnv()
+}
+
+func TestBindEnvsFromConfig_TopLevelOverride(t *testing.T) {
+	setupViper("test")
+	t.Setenv("TEST_NAME", "from-env")
+
+	cfg := newTestConfig()
+	bindEnvsFromConfig(cfg)
+	require.NoError(t, viper.Unmarshal(cfg, initDecoderConfig))
+
+	assert.Equal(t, "from-env", cfg.Name)
+}
+
+// TestBindEnvsFromConfig_NestedNilPointerOverride is the regression guard: the
+// TLS section is nil in the default config, so the previous marshal-of-value
+// implementation never bound TEST_TLS_CACERT and this override was silently
+// dropped. Enumerating keys from the type closes that gap.
+func TestBindEnvsFromConfig_NestedNilPointerOverride(t *testing.T) {
+	setupViper("test")
+	t.Setenv("TEST_TLS_CACERT", "/etc/ssl/ca.crt")
+
+	cfg := newTestConfig()
+	require.Nil(t, cfg.TLS, "TLS should start nil to model the default config")
+
+	bindEnvsFromConfig(cfg)
+	require.NoError(t, viper.Unmarshal(cfg, initDecoderConfig))
+
+	require.NotNil(t, cfg.TLS, "nested env override should materialize the TLS section")
+	assert.Equal(t, "/etc/ssl/ca.crt", cfg.TLS.CACert)
+}
+
+func TestBindEnvsFromConfig_NoEnvKeepsDefaults(t *testing.T) {
+	setupViper("test")
+
+	cfg := newTestConfig()
+	bindEnvsFromConfig(cfg)
+	require.NoError(t, viper.Unmarshal(cfg, initDecoderConfig))
+
+	assert.Equal(t, "default-name", cfg.Name)
+	assert.Nil(t, cfg.TLS, "no env set should leave the optional section nil")
+}
+
+// TestBindEnvsFromConfig_RealSchedulerConfig exercises the actual production
+// config type end-to-end, including a nested key (Server.TLS.CACert) that lives
+// under a pointer left nil by config.New() — the regression the fix targets.
+func TestBindEnvsFromConfig_RealSchedulerConfig(t *testing.T) {
+	setupViper("scheduler")
+	t.Setenv("SCHEDULER_SERVER_HOST", "override-host")
+	t.Setenv("SCHEDULER_SERVER_TLS_CACERT", "/etc/ssl/ca.crt")
+
+	cfg := schedulerconfig.New()
+	require.Nil(t, cfg.Server.TLS, "default scheduler config leaves Server.TLS nil")
+
+	bindEnvsFromConfig(cfg)
+	require.NoError(t, viper.Unmarshal(cfg, initDecoderConfig))
+
+	assert.Equal(t, "override-host", cfg.Server.Host, "env should override a populated default")
+
+	require.NotNil(t, cfg.Server.TLS, "nested env override should materialize the TLS section")
+	assert.Equal(t, "/etc/ssl/ca.crt", cfg.Server.TLS.CACert)
+}