Don't send logs if there are no metrics

Author: daszwarc

emf/logger.go

@@ -159,8 +159,9 @@ func (l *Logger) Log() {
 		metrics = append(metrics, l.defaultContext.metricDirective)
 	}
 	for _, v := range l.contexts {
-		// TODO check if not empty as above?
-		metrics = append(metrics, v.metricDirective)
+		if len(v.metricDirective.Metrics) > 0 {
+			metrics = append(metrics, v.metricDirective)
+		}
 	}
 
 	if len(metrics) == 0 {

emf/logger_test.go

@@ -2,12 +2,12 @@ package emf_test
 
 import (
 	"bytes"
+	"github.com/kinbiko/jsonassert"
+	"github.com/prozz/aws-embedded-metrics-golang/emf"
+	"github.com/tj/assert"
 	"io/ioutil"
 	"os"
 	"testing"
-
-	"github.com/kinbiko/jsonassert"
-	"github.com/prozz/aws-embedded-metrics-golang/emf"
 )
 
 func TestEmf(t *testing.T) {
@@ -171,11 +171,6 @@ func TestEmf(t *testing.T) {
 			},
 			expected: "testdata/16.json",
 		},
-		{
-			name:     "no metrics set",
-			given:    func(logger *emf.Logger) {},
-			expected: "testdata/17.txt",
-		},
 	}
 
 	for _, tc := range tcs {
@@ -198,6 +193,23 @@ func TestEmf(t *testing.T) {
 			jsonassert.New(t).Assertf(buf.String(), string(f))
 		})
 	}
+
+	t.Run("no metrics set", func(t *testing.T) {
+		var buf bytes.Buffer
+		logger := emf.NewFor(&buf)
+		logger.Log()
+
+		assert.Empty(t, buf.String())
+	})
+
+	t.Run("new context, no metrics set", func(t *testing.T) {
+		var buf bytes.Buffer
+		logger := emf.NewFor(&buf)
+		logger.NewContext().Namespace("galaxy")
+		logger.Log()
+
+		assert.Empty(t, buf.String())
+	})
 }
 
 func TestLogger_LogSampled(t *testing.T) {

emf/testdata/17.txt

@@ -4,4 +4,5 @@ go 1.14
 
 require (
 	github.com/kinbiko/jsonassert v1.0.1
+	github.com/tj/assert v0.0.3
 )

go.mod

@@ -1,4 +1,17 @@
-git.naspersclassifieds.com/Pawel.Rozynek/aws-embedded-metrics-golang v0.0.0-20200605204858-b8ba9d02bc89 h1:CBLZZgcGL8VUl9+N8t71yZgMF16Qwk4i5l7Lw1LafQY=
-git.naspersclassifieds.com/Pawel.Rozynek/aws-embedded-metrics-golang v0.0.0-20200605204858-b8ba9d02bc89/go.mod h1:GLqH9LFDevA5Hss5EuOU+N77htYcG4/d3X2JMMo9yUY=
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/kinbiko/jsonassert v1.0.1 h1:8gdLmUaPWuxk2TzQSofKRqatFH6zwTF6AsUH4bugJYY=
 github.com/kinbiko/jsonassert v1.0.1/go.mod h1:QRwBwiAsrcJpjw+L+Q4WS8psLxuUY+HylVZS/4j74TM=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd0=
+github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
+github.com/tj/assert v0.0.3 h1:Df/BlaZ20mq6kuai7f5z2TvPFiwC3xaWJSDQNiIS3Rk=
+github.com/tj/assert v0.0.3/go.mod h1:Ne6X72Q+TB1AteidzQncjw9PabbMp4PBMZ1k+vd1Pvk=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
+gopkg.in/yaml.v3 v3.0.0-20200605160147-a5ece683394c h1:grhR+C34yXImVGp7EzNk+DTIk+323eIUWOmEevy6bDo=
+gopkg.in/yaml.v3 v3.0.0-20200605160147-a5ece683394c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=