Merge pull request #16 from asecurityteam/setting-to-omit-path

allow users of lib to omit 'path' tag

transport.go

@@ -24,8 +24,9 @@ type MetricsConfig struct {
 	PutIdle           string `description:"Name of idle connection return count metric."`
 	BackendTag        string `description:"Name of the tag containing the backend reference."`
 	PathTag           string `description:"Name of the tag containing the path reference."`
-	Backend           string `description:"Static value for the backend metric."`
-	Path              string `description:"Static value for the path metric. If not specified, will be generated for each request."`
+	Backend           string `description:"Static value for the backend tag metric."`
+	Path              string `description:"Static value for the path tag metric. If not specified, will be generated for each request."`
+	OmitPathTag       bool   `description:"Boolean to omit path tag metric.  Omitting the path tag may be desirable to avoid cardinality explosions for paths that vary greatly."`
 }
 
 // Name of the config root.
@@ -59,6 +60,7 @@ func (*MetricsComponent) Settings() *MetricsConfig {
 		PathTag:           "client_path",
 		Backend:           "",
 		Path:              "",
+		OmitPathTag:       false,
 	}
 }
 
@@ -93,12 +95,14 @@ func (c *MetricsComponent) New(_ context.Context, conf *MetricsConfig) (func(htt
 		statstransport.TransportOptionTag(conf.BackendTag, conf.Backend),
 	}
 
-	if conf.Path == "" {
-		options = append(options, statstransport.TransportOptionRequestTag(func(r *http.Request) (string, string) {
-			return conf.PathTag, r.URL.EscapedPath()
-		}))
-	} else {
-		options = append(options, statstransport.TransportOptionTag(conf.PathTag, conf.Path))
+	if !conf.OmitPathTag {
+		if conf.Path == "" {
+			options = append(options, statstransport.TransportOptionRequestTag(func(r *http.Request) (string, string) {
+				return conf.PathTag, r.URL.EscapedPath()
+			}))
+		} else {
+			options = append(options, statstransport.TransportOptionTag(conf.PathTag, conf.Path))
+		}
 	}
 
 	return statstransport.NewTransport(options...), nil

transport_test.go

@@ -2,14 +2,22 @@ package httpstats
 
 import (
 	"context"
+	"fmt"
 	"net/http"
+	"net/url"
 	"reflect"
 	"testing"
+	"time"
 
 	"github.com/asecurityteam/settings"
+	"github.com/rs/xstats"
 	"github.com/stretchr/testify/assert"
 )
 
+const (
+	testdependency = "testdependency"
+)
+
 func TestMetricsConfigName(t *testing.T) {
 	Config := MetricsConfig{}
 	assert.Equal(t, "metrics", Config.Name())
@@ -28,7 +36,7 @@ func TestMetricsComponentNew(t *testing.T) {
 func TestNew(t *testing.T) {
 	src := settings.NewMapSource(map[string]interface{}{
 		"metrics": map[string]interface{}{
-			"backend": "testdependency",
+			"backend": testdependency,
 		},
 	})
 	wrapper, err := New(context.Background(), src)
@@ -37,7 +45,7 @@ func TestNew(t *testing.T) {
 
 	tr := wrapper(http.DefaultTransport)
 	assert.Equal(
-		t, "client_dependency:testdependency",
+		t, fmt.Sprintf("client_dependency:%s", testdependency),
 		reflect.Indirect(reflect.ValueOf(tr)).FieldByName("tags").Index(0).String(),
 	)
 }
@@ -54,27 +62,94 @@ func TestMetricsComponentNewNoDependencyError(t *testing.T) {
 func TestMetricsComponentNewStaticPath(t *testing.T) {
 	cmp := NewComponent()
 	conf := cmp.Settings()
-	conf.Backend = "testdependency"
+	conf.Backend = testdependency
+	conf.Path = "/foo"
+	wrapper, err := cmp.New(context.Background(), conf)
+	assert.Nil(t, err)
+	assert.IsType(t, wrapper, func(next http.RoundTripper) http.RoundTripper { return nil }, wrapper)
+
+	tr := wrapper(http.DefaultTransport)
+	tags := reflect.Indirect(reflect.ValueOf(tr)).FieldByName("tags")
+	for i := 0; i < tags.Len(); i++ {
+		assert.Contains(t, []string{fmt.Sprintf("client_dependency:%s", testdependency), "client_path:/foo"}, tags.Index(i).String())
+	}
+}
+
+func TestMetricsComponentNonStaticPath(t *testing.T) {
+	cmp := NewComponent()
+	conf := cmp.Settings()
+	conf.Backend = testdependency
+	wrapper, err := cmp.New(context.Background(), conf)
+	assert.Nil(t, err)
+	assert.IsType(t, wrapper, func(next http.RoundTripper) http.RoundTripper { return nil }, wrapper)
+
+	tr := wrapper(http.DefaultTransport)
+
+	request := http.Request{URL: &url.URL{Path: `/some/random/path`}}
+
+	xStater := XStater{}
+	xStaterContext := xstats.NewContext(context.Background(), &xStater)
+
+	request = *request.WithContext(xStaterContext)
+
+	_, _ = tr.RoundTrip(&request)
+
+	expectedTags := []string{
+		"client_path:/some/random/path",
+		fmt.Sprintf("client_dependency:%s", testdependency),
+		"method:",
+		"status_code:502",
+		"status:error",
+	}
+
+	assert.Equal(t, len(expectedTags), len(xStater.TimingTags))
+
+	for i := 0; i < len(expectedTags); i++ {
+		assert.Contains(t, expectedTags, xStater.TimingTags[i])
+	}
+}
+
+func TestMetricsComponentNewStaticPathOmitPath(t *testing.T) {
+	cmp := NewComponent()
+	conf := cmp.Settings()
+	conf.Backend = testdependency
 	conf.Path = "/foo"
+	conf.OmitPathTag = true
 	wrapper, err := cmp.New(context.Background(), conf)
 	assert.Nil(t, err)
 	assert.IsType(t, wrapper, func(next http.RoundTripper) http.RoundTripper { return nil }, wrapper)
 
 	tr := wrapper(http.DefaultTransport)
 	tags := reflect.Indirect(reflect.ValueOf(tr)).FieldByName("tags")
 	for i := 0; i < tags.Len(); i++ {
-		assert.Contains(t, []string{"client_dependency:testdependency", "client_path:/foo"}, tags.Index(i).String())
+		assert.Contains(t, []string{fmt.Sprintf("client_dependency:%s", testdependency)}, tags.Index(i).String())
 	}
 }
 
 func TestMetricsComponentNewNoPathGiven(t *testing.T) {
 	cmp := NewComponent()
 	conf := cmp.Settings()
-	conf.Backend = "testdependency"
+	conf.Backend = testdependency
 	wrapper, err := cmp.New(context.Background(), conf)
 	assert.Nil(t, err)
 	assert.IsType(t, wrapper, func(next http.RoundTripper) http.RoundTripper { return nil }, wrapper)
 
 	tr := wrapper(http.DefaultTransport)
 	assert.Equal(t, 1, reflect.Indirect(reflect.ValueOf(tr)).FieldByName("requestTaggers").Len())
 }
+
+// XStater a rudimentary recorder of emitted stats things.  Add recordings for the stat name and values if you need them
+type XStater struct {
+	AddTagsTags   []string
+	CountTags     []string
+	GaugeTags     []string
+	HistogramTags []string
+	TimingTags    []string
+}
+
+func (x *XStater) AddTags(tags ...string)                                  { x.AddTagsTags = tags }
+func (x *XStater) GetTags() []string                                       { return x.AddTagsTags }
+func (x *XStater) Gauge(stat string, value float64, tags ...string)        { x.GaugeTags = tags }
+func (x *XStater) Count(stat string, count float64, tags ...string)        { x.CountTags = tags }
+func (x *XStater) Histogram(stat string, value float64, tags ...string)    { x.HistogramTags = tags }
+func (x *XStater) Timing(stat string, value time.Duration, tags ...string) { x.TimingTags = tags }