MM-28859 Add feature flag managment system using split.io and remove viper. (#15954)

* Add feature flag managment system using split.io and remove viper.

* Fixing tests.

* Attempt to fix postgres tests.

* Fix watch filepath for advanced logging.

* Review fixes.

* Some error wrapping.

* Remove unessisary store interface.

* Desanitize SplitKey

* Simplify.

* Review feedback.

* Rename split mlog adatper to split logger.

* fsInner

* Style.

* Restore oldcfg test.

* Downgrading non-actionable feature flag errors to warnings.

Co-authored-by: Mattermod <mattermod@users.noreply.github.com>

config/common_test.go

@@ -76,61 +76,63 @@ func init() {
 
 func TestMergeConfigs(t *testing.T) {
 	t.Run("merge two default configs with different salts/keys", func(t *testing.T) {
-		base, err := config.NewMemoryStore()
-		require.NoError(t, err)
-		patch, err := config.NewMemoryStore()
+		base := &model.Config{}
+		base.SetDefaults()
+		patch := &model.Config{}
+		patch.SetDefaults()
+
+		merged, err := config.Merge(base, patch, nil)
 		require.NoError(t, err)
 
-		merged, err := config.Merge(base.Get(), patch.Get(), nil)
-		require.NoError(t, err)
-
-		assert.Equal(t, patch.Get(), merged)
+		assert.Equal(t, patch, merged)
 	})
 	t.Run("merge identical configs", func(t *testing.T) {
-		base, err := config.NewMemoryStore()
-		require.NoError(t, err)
-		patch := base.Get().Clone()
+		base := &model.Config{}
+		base.SetDefaults()
+		patch := base.Clone()
 
-		merged, err := config.Merge(base.Get(), patch, nil)
+		merged, err := config.Merge(base, patch, nil)
 		require.NoError(t, err)
 
-		assert.Equal(t, base.Get(), merged)
+		assert.Equal(t, base, merged)
 		assert.Equal(t, patch, merged)
 	})
 	t.Run("merge configs with a different setting", func(t *testing.T) {
-		base, err := config.NewMemoryStore()
-		require.NoError(t, err)
-		patch := base.Get().Clone()
+		base := &model.Config{}
+		base.SetDefaults()
+		patch := base.Clone()
 		patch.ServiceSettings.SiteURL = newString("http://newhost.ca")
 
-		merged, err := config.Merge(base.Get(), patch, nil)
+		merged, err := config.Merge(base, patch, nil)
 		require.NoError(t, err)
 
-		assert.NotEqual(t, base.Get(), merged)
+		assert.NotEqual(t, base, merged)
 		assert.Equal(t, patch, merged)
 	})
 	t.Run("merge default config with changes from a mostly nil patch", func(t *testing.T) {
-		base, err := config.NewMemoryStore()
-		require.NoError(t, err)
+		base := &model.Config{}
+		base.SetDefaults()
 		patch := &model.Config{}
 		patch.ServiceSettings.SiteURL = newString("http://newhost.ca")
 		patch.GoogleSettings.Enable = newBool(true)
 
-		expected := base.Get().Clone()
+		expected := base.Clone()
 		expected.ServiceSettings.SiteURL = newString("http://newhost.ca")
 		expected.GoogleSettings.Enable = newBool(true)
 
-		merged, err := config.Merge(base.Get(), patch, nil)
+		merged, err := config.Merge(base, patch, nil)
 		require.NoError(t, err)
 
-		assert.NotEqual(t, base.Get(), merged)
+		assert.NotEqual(t, base, merged)
 		assert.NotEqual(t, patch, merged)
 		assert.Equal(t, expected, merged)
 	})
 }
 
 func TestConfigEnvironmentOverrides(t *testing.T) {
-	base, err := config.NewMemoryStore()
+	memstore, err := config.NewMemoryStore()
+	require.NoError(t, err)
+	base, err := config.NewStoreFromBacking(memstore)
 	require.NoError(t, err)
 	originalConfig := &model.Config{}
 	originalConfig.ServiceSettings.SiteURL = newString("http://notoverriden.ca")
@@ -157,7 +159,9 @@ func TestRemoveEnvironmentOverrides(t *testing.T) {
 	os.Setenv("MM_SERVICESETTINGS_SITEURL", "http://overridden.ca")
 	defer os.Unsetenv("MM_SERVICESETTINGS_SITEURL")
 
-	base, err := config.NewMemoryStore()
+	memstore, err := config.NewMemoryStore()
+	require.NoError(t, err)
+	base, err := config.NewStoreFromBacking(memstore)
 	require.NoError(t, err)
 	oldCfg := base.Get()
 	assert.Equal(t, "http://overridden.ca", *oldCfg.ServiceSettings.SiteURL)
@@ -165,22 +169,5 @@ func TestRemoveEnvironmentOverrides(t *testing.T) {
 	assert.Equal(t, "", *newCfg.ServiceSettings.SiteURL)
 }
 
-func TestRemoveNonPersistable(t *testing.T) {
-	os.Setenv("MM_SERVICESETTINGS_SITEURL", "http://overridden.ca")
-	defer os.Unsetenv("MM_SERVICESETTINGS_SITEURL")
-
-	base, err := config.NewMemoryStore()
-	require.NoError(t, err)
-	oldCfg := base.Get()
-	assert.Equal(t, "http://overridden.ca", *oldCfg.ServiceSettings.SiteURL)
-	oldCfg.FeatureFlags = &model.FeatureFlags{
-		TestFeature: "teststring",
-	}
-
-	newCfg := base.RemoveNonPersistable(oldCfg)
-	assert.Equal(t, "", *newCfg.ServiceSettings.SiteURL)
-	assert.Nil(t, newCfg.FeatureFlags)
-}
-
 func newBool(b bool) *bool       { return &b }
 func newString(s string) *string { return &s }