rename metrics

closes #4

CHANGES.org

@@ -4,3 +4,4 @@
 - log failure to graphite when fetch fails (if ~FailureMetric~ is
   defined for the endpoint)
 - metric ignore list
+- metric renaming

README.org

@@ -54,6 +54,15 @@ Timeout = 3000
         URL = "http://localhost:14002/debug/vars"
         Prefix = "apps.app2"
         FailureMetric = "apps.app1.failure"
+
+[[rename]]
+From = "BuckHashSys"
+To = "buck_hash_sys"
+
+[[rename]]
+From = "Sys"
+To = "sys"
+
 #+END_SRC
 
 The top level fields that need to be set are:
@@ -86,6 +95,13 @@ Optionall, it also supports:
 ~CheckInterval~ and ~Timeout~ can also be individually overridden for
 each endpoint as well.
 
+Finally, you can tell it to rename metrics. Eg, expvar generally
+outputs camelCase variables, but perhaps you have standardized on all
+lower case and underscores for your graphite metrics. Just add as many
+~[[[[rename]]]]~ blocks as you need (yeah, you have to explicitly do
+each. If you want to add support for general renaming policies, I'd
+take a patch). That can also be overridden on a per-endpoint basis.
+
 ** Additional Features
 
 Samlare will respond to a ~SIGHUP~ signal by reloading its config

endpoint.go

@@ -25,6 +25,7 @@ type endpoint struct {
 	checkInterval  int
 	timeout        int
 	ignoreMetrics  map[string]struct{}
+	renames        map[string]string
 	graphiteServer Submitable
 	fetcher        fetcher
 	logger         log.Logger
@@ -35,7 +36,7 @@ type metric struct {
 	Value float64
 }
 
-func newEndpoint(c endpointconfig, interval int, timeout int, ignoreMetrics []string, g Submitable, fetcher fetcher, logger log.Logger) *endpoint {
+func newEndpoint(c endpointconfig, interval int, timeout int, ignoreMetrics []string, renameMetrics []renameConfig, g Submitable, fetcher fetcher, logger log.Logger) *endpoint {
 	if c.CheckInterval != 0 {
 		interval = c.CheckInterval
 	}
@@ -49,6 +50,10 @@ func newEndpoint(c endpointconfig, interval int, timeout int, ignoreMetrics []st
 	for _, m := range ignoreMetrics {
 		ignoreMap[m] = struct{}{}
 	}
+	renameMap := make(map[string]string)
+	for _, r := range c.Renames {
+		renameMap[r.From] = r.To
+	}
 
 	return &endpoint{
 		url:            c.URL,
@@ -57,6 +62,7 @@ func newEndpoint(c endpointconfig, interval int, timeout int, ignoreMetrics []st
 		failureMetric:  c.FailureMetric,
 		timeout:        timeout,
 		ignoreMetrics:  ignoreMap,
+		renames:        renameMap,
 		graphiteServer: g,
 		fetcher:        fetcher,
 		logger:         logger,
@@ -102,7 +108,7 @@ func (e *endpoint) Gather(ctx context.Context) []metric {
 	}
 	e.logger.Log("msg", "good fetch")
 
-	metrics = metricsFromMap(m, e.prefix, e.ignoreMetrics)
+	metrics = metricsFromMap(m, e.prefix, e.ignoreMetrics, e.renames)
 	// success
 	if e.failureMetric != "" {
 		s := metric{Name: e.failureMetric, Value: 0.0}
@@ -112,19 +118,23 @@ func (e *endpoint) Gather(ctx context.Context) []metric {
 	return metrics
 }
 
-func metricsFromMap(m map[string]interface{}, prefix string, ignore map[string]struct{}) []metric {
+func metricsFromMap(m map[string]interface{}, prefix string, ignore map[string]struct{}, renames map[string]string) []metric {
 	var metrics []metric
 	for k, v := range m {
-		_, exists := ignore[k]
-		if exists {
+		_, ok := ignore[k]
+		if ok {
 			continue
 		}
+		t, ok := renames[k]
+		if ok {
+			k = t
+		}
 		key := fmt.Sprintf("%s.%s", prefix, k)
 		switch vv := v.(type) {
 		case float64:
 			metrics = append(metrics, metric{key, vv})
 		case map[string]interface{}:
-			nmetrics := metricsFromMap(vv, key, ignore)
+			nmetrics := metricsFromMap(vv, key, ignore, renames)
 			for _, met := range nmetrics {
 				metrics = append(metrics, met)
 			}

endpoint_test.go

@@ -18,20 +18,38 @@ func Test_metricsFromMap(t *testing.T) {
 	var f interface{}
 	json.Unmarshal([]byte(data), &f)
 	ignore := make(map[string]struct{})
-	metrics := metricsFromMap(f.(map[string]interface{}), "", ignore)
+	renames := make(map[string]string)
+	metrics := metricsFromMap(f.(map[string]interface{}), "", ignore, renames)
 	if len(metrics) != 2 {
 		t.Error("wrong number of metrics found")
 	}
 
 	data = `{"foo": 10, "bar": 5, "baz": {"blah": 3}}`
 	json.Unmarshal([]byte(data), &f)
-	metrics = metricsFromMap(f.(map[string]interface{}), "", ignore)
+	metrics = metricsFromMap(f.(map[string]interface{}), "", ignore, renames)
 	if len(metrics) != 3 {
 		t.Error("wrong number of metrics found")
 	}
 
 }
 
+func Test_metricsFromMapRename(t *testing.T) {
+	data := `{"foo": 10, "bar": 5}`
+	var f interface{}
+	json.Unmarshal([]byte(data), &f)
+	ignore := make(map[string]struct{})
+	renames := make(map[string]string)
+	renames["foo"] = "FOO"
+	renames["bar"] = "BAR"
+	metrics := metricsFromMap(f.(map[string]interface{}), "", ignore, renames)
+	if len(metrics) != 2 {
+		t.Error("wrong number of metrics found")
+	}
+	if metrics[0].Name != ".FOO" || metrics[1].Name != ".BAR" {
+		t.Error("didn't rename metric correctly", metrics[0].Name, metrics[1].Name)
+	}
+}
+
 func dummyLogger() log.Logger {
 	devNull, _ := os.Open("/dev/null")
 	w := log.NewSyncWriter(devNull)
@@ -47,7 +65,7 @@ func Test_newEndpoint(t *testing.T) {
 		Timeout:       60,
 	}
 	g := newGraphiteServer("1.2.3.4", 2003)
-	e := newEndpoint(c, 60, 60, []string{}, g, httpFetcher{}, dummyLogger())
+	e := newEndpoint(c, 60, 60, []string{}, []renameConfig{}, g, httpFetcher{}, dummyLogger())
 	if e.url != c.URL {
 		t.Error("lost the URL")
 	}
@@ -67,7 +85,7 @@ func Test_Submit(t *testing.T) {
 		Timeout:       60,
 	}
 	var g dummyGraphite
-	e := newEndpoint(c, 60, 60, []string{}, g, httpFetcher{}, dummyLogger())
+	e := newEndpoint(c, 60, 60, []string{}, []renameConfig{}, g, httpFetcher{}, dummyLogger())
 	var m []metric
 	err := e.Submit(m)
 	if err != nil {
@@ -117,7 +135,7 @@ func Test_Fetch(t *testing.T) {
 		Timeout:       60,
 	}
 	g := newGraphiteServer("1.2.3.4", 2003)
-	e := newEndpoint(c, 60, 60, []string{}, g, dummyFetcher{}, dummyLogger())
+	e := newEndpoint(c, 60, 60, []string{}, []renameConfig{}, g, dummyFetcher{}, dummyLogger())
 
 	ctx := context.TODO()
 
@@ -126,7 +144,8 @@ func Test_Fetch(t *testing.T) {
 		t.Error("dummy fetcher shouldn't fail")
 	}
 	ignore := make(map[string]struct{})
-	metrics := metricsFromMap(d, "", ignore)
+	renames := make(map[string]string)
+	metrics := metricsFromMap(d, "", ignore, renames)
 	if len(metrics) != 2 {
 		t.Error("wrong number of metrics found")
 	}
@@ -141,7 +160,7 @@ func Test_Gather(t *testing.T) {
 		Timeout:       60,
 	}
 	g := newGraphiteServer("1.2.3.4", 2003)
-	e := newEndpoint(c, 60, 60, []string{}, g, dummyFetcher{}, dummyLogger())
+	e := newEndpoint(c, 60, 60, []string{}, []renameConfig{}, g, dummyFetcher{}, dummyLogger())
 
 	ctx := context.TODO()
 	metrics := e.Gather(ctx)
@@ -161,7 +180,7 @@ func Test_GatherIgnoreMetric(t *testing.T) {
 		IgnoreMetrics: []string{"foo"},
 	}
 	g := newGraphiteServer("1.2.3.4", 2003)
-	e := newEndpoint(c, 60, 60, []string{}, g, dummyFetcher{}, dummyLogger())
+	e := newEndpoint(c, 60, 60, []string{}, []renameConfig{}, g, dummyFetcher{}, dummyLogger())
 
 	ctx := context.TODO()
 	metrics := e.Gather(ctx)
@@ -181,7 +200,7 @@ func Test_GatherWithFailureMetric(t *testing.T) {
 		FailureMetric: "failure",
 	}
 	g := newGraphiteServer("1.2.3.4", 2003)
-	e := newEndpoint(c, 60, 60, []string{}, g, dummyFetcher{}, dummyLogger())
+	e := newEndpoint(c, 60, 60, []string{}, []renameConfig{}, g, dummyFetcher{}, dummyLogger())
 
 	ctx := context.TODO()
 	metrics := e.Gather(ctx)
@@ -200,7 +219,7 @@ func Test_Run(t *testing.T) {
 		Timeout:       60,
 	}
 	var g dummyGraphite
-	e := newEndpoint(c, 60, 60, []string{}, g, dummyFetcher{}, dummyLogger())
+	e := newEndpoint(c, 60, 60, []string{}, []renameConfig{}, g, dummyFetcher{}, dummyLogger())
 
 	ctx, cancel := context.WithCancel(context.TODO())
 
@@ -216,7 +235,7 @@ func Test_Run(t *testing.T) {
 		Timeout:       60,
 	}
 
-	e = newEndpoint(c, 60, 60, []string{}, g, dummyFetcher{}, dummyLogger())
+	e = newEndpoint(c, 60, 60, []string{}, []renameConfig{}, g, dummyFetcher{}, dummyLogger())
 
 	ctx, cancel = context.WithCancel(context.TODO())
 

samlare.go

@@ -11,13 +11,19 @@ import (
 	"github.com/go-kit/kit/log"
 )
 
+type renameConfig struct {
+	From string
+	To   string
+}
+
 type endpointconfig struct {
 	URL           string
 	Prefix        string
 	CheckInterval int
 	Timeout       int
 	FailureMetric string
 	IgnoreMetrics []string
+	Renames       []renameConfig
 }
 
 type config struct {
@@ -26,6 +32,7 @@ type config struct {
 	CheckInterval int
 	Timeout       int
 	IgnoreMetrics []string
+	Renames       []renameConfig
 
 	Endpoints map[string]endpointconfig
 }
@@ -90,7 +97,7 @@ func startEndpoints(conf *config, logger log.Logger) context.CancelFunc {
 
 	for k, endpoint := range conf.Endpoints {
 		elogger := log.With(logger, "endpoint", k)
-		e := newEndpoint(endpoint, conf.CheckInterval, conf.Timeout, conf.IgnoreMetrics, g, httpFetcher{}, elogger)
+		e := newEndpoint(endpoint, conf.CheckInterval, conf.Timeout, conf.IgnoreMetrics, conf.Renames, g, httpFetcher{}, elogger)
 		go e.Run(ctx)
 	}
 

sample-config.toml

@@ -4,6 +4,15 @@ CheckInterval = 60000
 Timeout = 3000
 IgnoreMetrics = ["cmdline", "foo"]
 
+[[rename]]
+From = "Sys"
+To = "sys"
+
+[[rename]]
+From = "BuckHashSys"
+To = "buck_hash_sys"
+
+
 [endpoints]
 
   [endpoints.app1]