fix: clearer err msg when overriding an unknown provider type (#665)

cmd/slinky/config/config.go

@@ -133,14 +133,23 @@ func ReadOracleConfigWithOverrides(path string, marketMapProvider string) (confi
 // oracleConfigFromViper unmarshals an oracle config from viper, validates it, and returns it.
 func oracleConfigFromViper() (config.OracleConfig, error) {
 	var cfg config.OracleConfig
+	unmarshalMetadata := mapstructure.Metadata{}
 	if err := viper.Unmarshal(&cfg, func(c *mapstructure.DecoderConfig) {
 		c.ErrorUnused = true
+		c.Metadata = &unmarshalMetadata
 	}); err != nil {
 		return config.OracleConfig{}, err
 	}
 
 	// for each api-provider, we'll have to manually fill the endpoints
 	for _, provider := range cfg.Providers {
+		// if a provider was not unmarshaled correctly, surface that error
+		if provider.Name == "" {
+			if len(unmarshalMetadata.Unset) > 0 {
+				return config.OracleConfig{}, fmt.Errorf("overridden key %s does not correspond to a known provider", unmarshalMetadata.Unset[0])
+			}
+		}
+
 		// Update API endpoints
 		for i, endpoint := range provider.API.Endpoints {
 			provider.API.Endpoints[i], _ = updateEndpointFromEnvironment(endpoint, provider.Name, i, "api")

cmd/slinky/config/config_test.go

@@ -349,6 +349,52 @@ func TestReadOracleConfigWithOverrides(t *testing.T) {
 		require.Equal(t, expectedConfig.UpdateInterval, cfg.UpdateInterval)
 		require.Equal(t, expectedConfig.Metrics.PrometheusServerAddress, cfg.Metrics.PrometheusServerAddress)
 	})
+
+	t.Run("overriding a nonexistent provider via config fails", func(t *testing.T) {
+		// create a temp file in the current directory
+		tmpfile, err := os.CreateTemp("", "slinky-config-*.json")
+		require.NoError(t, err)
+
+		defer os.Remove(tmpfile.Name())
+
+		overrides := fmt.Sprintf(`
+		{
+			"updateInterval": "%s",
+			"metrics": {
+				"prometheusServerAddress": "%s"
+			},
+			"providers": {
+				"doesNotExist": {
+					"api": {
+						"endpoints": [
+							{
+								"url": "%s"
+							},
+							{
+								"url": "%s",
+								"authentication": {
+									"apiKey": "%s",
+									"apiKeyHeader": "%s"
+								}
+							}
+						]
+					}
+				}
+			}
+		}
+		`,
+			updateIntervalOverride,
+			prometheusServerOverride,
+			raydium.DefaultAPIConfig.Endpoints[0].URL,
+			endpointOverride.URL,
+			endpointOverride.Authentication.APIKey,
+			endpointOverride.Authentication.APIKeyHeader,
+		)
+		tmpfile.Write([]byte(overrides))
+
+		_, err = cmdconfig.ReadOracleConfigWithOverrides(tmpfile.Name(), marketmap.Name)
+		require.ErrorContains(t, err, "overridden key")
+	})
 }
 
 func TestOracleConfigWithExtraKeys(t *testing.T) {