Remove default value for "ffdx"

Handle it as a specific one-off instead of setting a Viper default.

Signed-off-by: Andrew Richardson <andrew.richardson@kaleido.io>

Author: awrichar

docs/reference/config.md

@@ -336,7 +336,7 @@ nav_order: 2
 
 |Key|Description|Type|Default Value|
 |---|-----------|----|-------------|
-|type|The Data Exchange plugin to use|`string`|`ffdx`
+|type|The Data Exchange plugin to use|`string`|`<nil>`
 
 ## dataexchange.ffdx
 

internal/dataexchange/dxfactory/factory.go

@@ -44,7 +44,7 @@ func InitConfig(config config.ArraySection) {
 }
 
 func InitConfigDeprecated(config config.Section) {
-	config.AddKnownKey(coreconfig.PluginConfigType, NewFFDXPluginName)
+	config.AddKnownKey(coreconfig.PluginConfigType)
 	for name, plugin := range pluginsByName {
 		plugin().InitConfig(config.SubSection(name))
 	}

internal/namespace/manager.go

@@ -47,6 +47,7 @@ import (
 	"github.com/hyperledger/firefly/pkg/identity"
 	"github.com/hyperledger/firefly/pkg/sharedstorage"
 	"github.com/hyperledger/firefly/pkg/tokens"
+	"github.com/spf13/viper"
 )
 
 var (
@@ -436,6 +437,10 @@ func (nm *namespaceManager) getDataExchangePlugins(ctx context.Context) (plugins
 	// check deprecated config
 	if len(plugins) == 0 {
 		pluginType := deprecatedDataexchangeConfig.GetString(coreconfig.PluginConfigType)
+		if pluginType == "" && viper.Get("dataexchange") != nil {
+			// very old config allowed omitting an explicit "type" for data exchange
+			pluginType = dxfactory.NewFFDXPluginName
+		}
 		if pluginType != "" {
 			plugin, err := dxfactory.GetPlugin(ctx, pluginType)
 			if err != nil {

internal/namespace/manager_test.go

@@ -563,6 +563,23 @@ func TestDeprecatedDataExchangePluginBadType(t *testing.T) {
 	assert.Regexp(t, "FF10213.*wrong", err)
 }
 
+func TestDeprecatedDataExchangePluginDefaultType(t *testing.T) {
+	nm := newTestNamespaceManager(true)
+	defer nm.cleanup(t)
+	dxfactory.InitConfigDeprecated(deprecatedDataexchangeConfig)
+
+	viper.SetConfigType("yaml")
+	err := viper.ReadConfig(strings.NewReader(`
+  dataexchange:
+    ffdx:
+      url: http://dx
+  `))
+	assert.NoError(t, err)
+
+	_, err = nm.getDataExchangePlugins(context.Background())
+	assert.NoError(t, err)
+}
+
 func TestDataExchangePlugin(t *testing.T) {
 	nm := newTestNamespaceManager(true)
 	defer nm.cleanup(t)