Merge configs section by section

Signed-off-by: Maksym Pavlenko <makpav@amazon.com>

services/server/config/config.go

@@ -297,8 +297,27 @@ func resolveImports(parent string, imports []string) ([]string, error) {
 // 0            1           1
 // []{"1"}      []{"2"}     []{"1","2"}
 // []{"1"}      []{}        []{"1"}
+// Maps merged by keys, but values are replaced entirely.
 func mergeConfig(to, from *Config) error {
-	return mergo.Merge(to, from, mergo.WithOverride, mergo.WithAppendSlice)
+	err := mergo.Merge(to, from, mergo.WithOverride, mergo.WithAppendSlice)
+	if err != nil {
+		return err
+	}
+
+	// Replace entire sections instead of merging map's values.
+	for k, v := range from.Plugins {
+		to.Plugins[k] = v
+	}
+
+	for k, v := range from.StreamProcessors {
+		to.StreamProcessors[k] = v
+	}
+
+	for k, v := range from.ProxyPlugins {
+		to.ProxyPlugins[k] = v
+	}
+
+	return nil
 }
 
 // V1DisabledFilter matches based on ID

services/server/config/config_test.go

@@ -36,6 +36,7 @@ func TestMergeConfigs(t *testing.T) {
 		State:            "old_state",
 		OOMScore:         1,
 		Timeouts:         map[string]string{"a": "1"},
+		StreamProcessors: map[string]StreamProcessor{"1": {Path: "2", Returns: "4"}, "2": {Path: "5"}},
 	}
 
 	b := &Config{
@@ -43,6 +44,7 @@ func TestMergeConfigs(t *testing.T) {
 		RequiredPlugins:  []string{"new_plugin1", "new_plugin2"},
 		OOMScore:         2,
 		Timeouts:         map[string]string{"b": "2"},
+		StreamProcessors: map[string]StreamProcessor{"1": {Path: "3"}},
 	}
 
 	err := mergeConfig(a, b)
@@ -55,6 +57,7 @@ func TestMergeConfigs(t *testing.T) {
 	assert.DeepEqual(t, a.RequiredPlugins, []string{"old_plugin", "new_plugin1", "new_plugin2"})
 	assert.DeepEqual(t, a.DisabledPlugins, []string{"old_plugin"})
 	assert.DeepEqual(t, a.Timeouts, map[string]string{"a": "1", "b": "2"})
+	assert.DeepEqual(t, a.StreamProcessors, map[string]StreamProcessor{"1": {Path: "3"}, "2": {Path: "5"}})
 }
 
 func TestResolveImports(t *testing.T) {