Add Carbon Plaintext

carbon/datapoint.go

@@ -0,0 +1,57 @@
+package carbon
+
+import "strconv"
+
+const (
+	nextPart      = " "
+	nextNode      = "."
+	nextTag       = ";"
+	nextTagValue  = "="
+	nextDatapoint = "\n"
+)
+
+// Datapoint is a value stored at a timestamp bucket.
+// If no value is recorded at a particular timestamp bucket in a series,
+// the value will be None (null).
+// Doc: https://graphite.readthedocs.io/en/latest/terminology.html
+type Datapoint struct {
+	path      string
+	value     float64
+	timestamp int64
+}
+
+// NewDatapoint is a datapoint building function
+func NewDatapoint(name string, value float64, timestamp int64) *Datapoint {
+	return &Datapoint{
+		path:      name,
+		value:     value,
+		timestamp: timestamp,
+	}
+}
+
+// WithPrefix adds provided prefix to datapoint
+// Every function call extends datapoint path from start
+// For example WithPrefix("second").WithPrefix("first") is
+// equal to WithPrefix("first.second")
+func (d *Datapoint) WithPrefix(prefix string) *Datapoint {
+	d.path = prefix + nextNode + d.path
+	return d
+}
+
+// WithTag adds provided tag=value pair to datapoint
+// Every function call extends datapoint path
+// For example WithTag("tag1","tag1Value").WithTag("tag2","tag2Value") adds ";tag1=tag1Value;tag2=tag2Value"
+// While WithTag("tag2","tag2Value").WithTag("tag1","tag1Value") adds ";tag2=tag2Value;tag1=tag1Value"
+func (d *Datapoint) WithTag(name, value string) *Datapoint {
+	d.path += nextTag + name + nextTagValue + value
+	return d
+}
+
+// Plaintext returns Graphite Plaintext record form of datapoint
+func (d *Datapoint) Plaintext() string {
+	var (
+		value     = strconv.FormatFloat(d.value, 'f', -1, 64)
+		timestamp = strconv.FormatInt(d.timestamp, 10)
+	)
+	return d.path + nextPart + value + nextPart + timestamp + nextDatapoint
+}

carbon/datapoint_test.go

@@ -0,0 +1,100 @@
+package carbon
+
+import "testing"
+
+func Test_NewDatapoint(t *testing.T) {
+	const (
+		testName             = "name"
+		testPrefixParentNode = "parent"
+		testPrefixChildNode  = "child"
+		testFirstTagName     = "firstTag"
+		testFirstTagValue    = "firstTagValue"
+		testSecondTagName    = "secondTag"
+		testSecondTagValue   = "secondTagValue"
+		testValue            = 3.14159265359
+		testTimestamp        = 1552503600
+	)
+
+	t.Run("simple", func(t *testing.T) {
+		var (
+			actual   = NewDatapoint(testName, testValue, testTimestamp).Plaintext()
+			expected = "name 3.14159265359 1552503600\n"
+		)
+		if actual != expected {
+			t.Fatalf("expected: %s\nactual: %s", expected, actual)
+		}
+	})
+
+	t.Run("with prefix", func(t *testing.T) {
+		var (
+			actual = NewDatapoint(testName, testValue, testTimestamp).
+				WithPrefix(testPrefixParentNode).
+				Plaintext()
+			expected = "parent.name 3.14159265359 1552503600\n"
+		)
+		if actual != expected {
+			t.Fatalf("expected: %s\nactual: %s", expected, actual)
+		}
+	})
+
+	t.Run("with nested prefix", func(t *testing.T) {
+		var (
+			actual = NewDatapoint(testName, testValue, testTimestamp).
+				WithPrefix(testPrefixChildNode).
+				WithPrefix(testPrefixParentNode).
+				Plaintext()
+			expected = "parent.child.name 3.14159265359 1552503600\n"
+		)
+		if actual != expected {
+			t.Fatalf("expected: %s\nactual: %s", expected, actual)
+		}
+	})
+
+	t.Run("with nested prefix and tag", func(t *testing.T) {
+		var (
+			recordForms = []string{
+				NewDatapoint(testName, testValue, testTimestamp).
+					WithPrefix(testPrefixChildNode).
+					WithPrefix(testPrefixParentNode).
+					WithTag(testFirstTagName, testFirstTagValue).
+					Plaintext(),
+				NewDatapoint(testName, testValue, testTimestamp).
+					WithTag(testFirstTagName, testFirstTagValue).
+					WithPrefix(testPrefixChildNode).
+					WithPrefix(testPrefixParentNode).
+					Plaintext(),
+			}
+			expected = "parent.child.name;firstTag=firstTagValue 3.14159265359 1552503600\n"
+		)
+		for _, actual := range recordForms {
+			if actual != expected {
+				t.Fatalf("expected: %s\nactual: %s", expected, actual)
+			}
+		}
+	})
+
+	t.Run("with nested prefix and tags", func(t *testing.T) {
+		var (
+			recordForms = []string{
+				NewDatapoint(testName, testValue, testTimestamp).
+					WithPrefix(testPrefixChildNode).
+					WithPrefix(testPrefixParentNode).
+					WithTag(testFirstTagName, testFirstTagValue).
+					WithTag(testSecondTagName, testSecondTagValue).
+					Plaintext(),
+				NewDatapoint(testName, testValue, testTimestamp).
+					WithTag(testFirstTagName, testFirstTagValue).
+					WithTag(testSecondTagName, testSecondTagValue).
+					WithPrefix(testPrefixChildNode).
+					WithPrefix(testPrefixParentNode).
+					Plaintext(),
+			}
+			expected = "parent.child.name;firstTag=firstTagValue;secondTag=secondTagValue 3.14159265359 1552503600\n"
+		)
+		for _, actual := range recordForms {
+			if actual != expected {
+				t.Fatalf("expected: %s\nactual: %s", expected, actual)
+			}
+		}
+	})
+}