changed ttl api.

census-instrumentation · Apr 23, 2019 · 717a54e · 717a54e
1 parent 4872670
commit 717a54e
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Showing 4 changed files with 34 additions and 29 deletions.
diff --git a/tag/map.go b/tag/map.go
@@ -155,7 +155,7 @@ func createMetadatas(mds ...Metadata) metadatas {
 			}
 		}
 	} else {
-		WithTTLUnlimitedPropagation()(&metas)
+		WithTTL(TTLUnlimitedPropagation)(&metas)
 	}
 	return metas
 

diff --git a/tag/map_codec.go b/tag/map_codec.go
@@ -170,7 +170,7 @@ func Encode(m *Map) []byte {
 	}
 	eg.writeByte(byte(tagsVersionID))
 	for k, v := range m.m {
-		if v.m.ttl == valueTTLUnlimitedPropagation {
+		if v.m.ttl.ttl == valueTTLUnlimitedPropagation {
 			eg.writeByte(byte(keyTypeString))
 			eg.writeStringWithVarintLen(k.name)
 			eg.writeBytesWithVarintLen([]byte(v.value))
@@ -230,7 +230,7 @@ func DecodeEach(bytes []byte, fn func(key Key, val string, md metadatas)) error
 		if !checkValue(val) {
 			return errInvalidValue
 		}
-		fn(key, val, createMetadatas(WithTTLUnlimitedPropagation()))
+		fn(key, val, createMetadatas(WithTTL(TTLUnlimitedPropagation)))
 		if err != nil {
 			return err
 		}

diff --git a/tag/map_test.go b/tag/map_test.go
@@ -24,8 +24,8 @@ import (
 )
 
 var (
-	ttlUnlimitedPropMd = createMetadatas(WithTTLUnlimitedPropagation())
-	ttlNoPropMd        = createMetadatas(WithTTLNoPropagation())
+	ttlUnlimitedPropMd = createMetadatas(WithTTL(TTLUnlimitedPropagation))
+	ttlNoPropMd        = createMetadatas(WithTTL(TTLNoPropagation))
 )
 
 func TestContext(t *testing.T) {
@@ -188,7 +188,7 @@ func TestNewMapWithMetadata(t *testing.T) {
 			name:    "from empty; insert",
 			initial: nil,
 			mods: []Mutator{
-				Insert(k5, "5", WithTTLNoPropagation()),
+				Insert(k5, "5", WithTTL(TTLNoPropagation)),
 				Insert(k4, "4"),
 			},
 			want: makeTestTagMapWithMetadata(
@@ -199,15 +199,15 @@ func TestNewMapWithMetadata(t *testing.T) {
 			name:    "from existing; insert existing",
 			initial: makeTestTagMapWithMetadata(tagContent{"5", ttlNoPropMd}),
 			mods: []Mutator{
-				Insert(k5, "5", WithTTLUnlimitedPropagation()),
+				Insert(k5, "5", WithTTL(TTLUnlimitedPropagation)),
 			},
 			want: makeTestTagMapWithMetadata(tagContent{"5", ttlNoPropMd}),
 		},
 		{
 			name:    "from existing; update non-existing",
 			initial: makeTestTagMapWithMetadata(tagContent{"5", ttlNoPropMd}),
 			mods: []Mutator{
-				Update(k4, "4", WithTTLUnlimitedPropagation()),
+				Update(k4, "4", WithTTL(TTLUnlimitedPropagation)),
 			},
 			want: makeTestTagMapWithMetadata(tagContent{"5", ttlNoPropMd}),
 		},
@@ -218,7 +218,7 @@ func TestNewMapWithMetadata(t *testing.T) {
 				tagContent{"4", ttlNoPropMd}),
 			mods: []Mutator{
 				Update(k5, "5"),
-				Update(k4, "4", WithTTLUnlimitedPropagation()),
+				Update(k4, "4", WithTTL(TTLUnlimitedPropagation)),
 			},
 			want: makeTestTagMapWithMetadata(
 				tagContent{"5", ttlUnlimitedPropMd},
@@ -230,7 +230,7 @@ func TestNewMapWithMetadata(t *testing.T) {
 				tagContent{"5", ttlNoPropMd},
 				tagContent{"4", ttlNoPropMd}),
 			mods: []Mutator{
-				Upsert(k4, "4", WithTTLUnlimitedPropagation()),
+				Upsert(k4, "4", WithTTL(TTLUnlimitedPropagation)),
 			},
 			want: makeTestTagMapWithMetadata(
 				tagContent{"5", ttlNoPropMd},
@@ -241,7 +241,7 @@ func TestNewMapWithMetadata(t *testing.T) {
 			initial: makeTestTagMapWithMetadata(
 				tagContent{"5", ttlNoPropMd}),
 			mods: []Mutator{
-				Upsert(k4, "4", WithTTLUnlimitedPropagation()),
+				Upsert(k4, "4", WithTTL(TTLUnlimitedPropagation)),
 				Upsert(k3, "3"),
 			},
 			want: makeTestTagMapWithMetadata(
@@ -264,18 +264,18 @@ func TestNewMapWithMetadata(t *testing.T) {
 			name:    "from empty; update invalid",
 			initial: nil,
 			mods: []Mutator{
-				Insert(k4, "4\x19", WithTTLUnlimitedPropagation()),
-				Upsert(k4, "4\x19", WithTTLUnlimitedPropagation()),
-				Update(k4, "4\x19", WithTTLUnlimitedPropagation()),
+				Insert(k4, "4\x19", WithTTL(TTLUnlimitedPropagation)),
+				Upsert(k4, "4\x19", WithTTL(TTLUnlimitedPropagation)),
+				Update(k4, "4\x19", WithTTL(TTLUnlimitedPropagation)),
 			},
 			want: nil,
 		},
 		{
 			name:    "from empty; insert partial",
 			initial: nil,
 			mods: []Mutator{
-				Upsert(k3, "3", WithTTLUnlimitedPropagation()),
-				Upsert(k4, "4\x19", WithTTLUnlimitedPropagation()),
+				Upsert(k3, "3", WithTTL(TTLUnlimitedPropagation)),
+				Upsert(k4, "4\x19", WithTTL(TTLUnlimitedPropagation)),
 			},
 			want: nil,
 		},

diff --git a/tag/metadata.go b/tag/metadata.go
@@ -23,25 +23,30 @@ const (
 	valueTTLUnlimitedPropagation = -1
 )
 
-type metadatas struct {
+// TTL is metadata that specifies number of hops a tag can propagate.
+// Details about TTL metadata is specified at https://github.com/census-instrumentation/opencensus-specs/blob/master/tags/TagMap.md#tagmetadata
+type TTL struct {
 	ttl int
 }
 
-// Metadata applies metadatas specified by the function.
-type Metadata func(*metadatas)
+var (
+	// TTLUnlimitedPropagation is TTL metadata that allows tag to propagate without any limits on number of hops.
+	TTLUnlimitedPropagation = TTL{ttl: valueTTLUnlimitedPropagation}
 
-// WithTTLNoPropagation applies metadata with ttl value of valueTTLNoPropagation.
-// It is predefined for convenience.
-func WithTTLNoPropagation() Metadata {
-	return func(m *metadatas) {
-		m.ttl = valueTTLNoPropagation
-	}
+	// TTLNoPropagation is TTL metadata that prevents tag from propagating.
+	TTLNoPropagation = TTL{ttl: valueTTLNoPropagation}
+)
+
+type metadatas struct {
+	ttl TTL
 }
 
-// WithTTLUnlimitedPropagation applies metadata with ttl value of valueTTLUnlimitedPropagation.
-// It is predefined for convenience.
-func WithTTLUnlimitedPropagation() Metadata {
+// Metadata applies metadatas specified by the function.
+type Metadata func(*metadatas)
+
+// WithTTL applies metadata with provided ttl.
+func WithTTL(ttl TTL) Metadata {
 	return func(m *metadatas) {
-		m.ttl = valueTTLUnlimitedPropagation
+		m.ttl = ttl
 	}
 }