feat(config): add -exact-config command line argument (go-graphite#262)

config/config.go

@@ -502,7 +502,7 @@ func PrintDefaultConfig() error {
 }
 
 // ReadConfig reads the content of the file with given name and process it to the *Config
-func ReadConfig(filename string) (*Config, []zap.Field, error) {
+func ReadConfig(filename string, exactConfig bool) (*Config, []zap.Field, error) {
 	var err error
 	var body []byte
 	if filename != "" {
@@ -512,11 +512,11 @@ func ReadConfig(filename string) (*Config, []zap.Field, error) {
 		}
 	}
 
-	return Unmarshal(body)
+	return Unmarshal(body, exactConfig)
 }
 
 // Unmarshal process the body to *Config
-func Unmarshal(body []byte) (cfg *Config, warns []zap.Field, err error) {
+func Unmarshal(body []byte, exactConfig bool) (cfg *Config, warns []zap.Field, err error) {
 	deprecations := make(map[string]error)
 
 	cfg = New()
@@ -529,9 +529,16 @@ func Unmarshal(body []byte) (cfg *Config, warns []zap.Field, err error) {
 				body = bytes.Replace(body, []byte("[logging]"), []byte("[[logging]]"), 1)
 			}
 		}
-		if err = toml.Unmarshal(body, cfg); err != nil {
+
+		decoder := toml.NewDecoder(bytes.NewReader(body))
+		decoder.Strict(exactConfig)
+
+		err := decoder.Decode(cfg)
+
+		if err != nil {
 			return nil, nil, err
 		}
+
 	}
 
 	if cfg.Logging == nil {

config/config_test.go

@@ -320,7 +320,7 @@ sample-initial = 10
 sample-thereafter = 12
 `,
 	)
-	config, _, err := Unmarshal(body)
+	config, _, err := Unmarshal(body, false)
 	expected := New()
 	require.NoError(t, err)
 
@@ -554,7 +554,7 @@ sample-initial = 10
 sample-thereafter = 12
 `,
 	)
-	config, _, err := Unmarshal(body)
+	config, _, err := Unmarshal(body, false)
 	expected := New()
 	require.NoError(t, err)
 	assert.NotNil(t, metrics.Graphite)
@@ -868,7 +868,7 @@ sample-initial = 10
 sample-thereafter = 12
 `,
 	)
-	config, _, err := Unmarshal(body)
+	config, _, err := Unmarshal(body, false)
 	expected := New()
 	require.NoError(t, err)
 	assert.NotNil(t, metrics.Graphite)
@@ -1072,7 +1072,7 @@ func TestGetQueryParamBroken(t *testing.T) {
 			  },
 			]`)
 
-	_, _, err := Unmarshal(config)
+	_, _, err := Unmarshal(config, false)
 	assert.Error(t, err)
 
 	config =
@@ -1087,7 +1087,7 @@ func TestGetQueryParamBroken(t *testing.T) {
 			  },
 			]`)
 
-	_, _, err = Unmarshal(config)
+	_, _, err = Unmarshal(config, false)
 	assert.Error(t, err)
 }
 
@@ -1250,7 +1250,7 @@ func TestGetQueryParam(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			if config, _, err := Unmarshal(tt.config); err == nil {
+			if config, _, err := Unmarshal(tt.config, false); err == nil {
 				for i := range config.ClickHouse.QueryParams {
 					config.ClickHouse.QueryParams[i].Limiter = nil
 				}

graphite-clickhouse.go

@@ -100,6 +100,7 @@ func main() {
 	configFile := flag.String("config", "/etc/graphite-clickhouse/graphite-clickhouse.conf", "Filename of config")
 	printDefaultConfig := flag.Bool("config-print-default", false, "Print default config")
 	checkConfig := flag.Bool("check-config", false, "Check config and exit")
+	exactConfig := flag.Bool("exact-config", false, "Ensure that all config params are contained in the target struct.")
 	buildTags := flag.Bool("tags", false, "Build tags table")
 	pprof := flag.String(
 		"pprof",
@@ -130,7 +131,7 @@ func main() {
 		return
 	}
 
-	cfg, warns, err := config.ReadConfig(*configFile)
+	cfg, warns, err := config.ReadConfig(*configFile, *exactConfig)
 	if err != nil {
 		log.Fatal(err)
 	}