Add Carbon Plaintext

carbon/datapoint.go

@@ -0,0 +1,74 @@
+package carbon
+
+import (
+	"bytes"
+	"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 {
+	buffer    *bytes.Buffer
+	value     float64
+	timestamp int64
+}
+
+// NewDatapoint is a datapoint building function
+func NewDatapoint(name string, value float64, timestamp int64) *Datapoint {
+	datapoint := &Datapoint{
+		buffer:    &bytes.Buffer{},
+		value:     value,
+		timestamp: timestamp,
+	}
+	datapoint.buffer.WriteString(name)
+	return datapoint
+}
+
+// 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 {
+	path := d.buffer.String()
+	d.buffer.Reset()
+	d.buffer.WriteString(prefix)
+	d.buffer.WriteString(nextNode)
+	d.buffer.WriteString(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.buffer.WriteString(nextTag)
+	d.buffer.WriteString(name)
+	d.buffer.WriteString(nextTagValue)
+	d.buffer.WriteString(value)
+	return d
+}
+
+// String returns Graphite Plaintext record form of datapoint
+func (d *Datapoint) String() string {
+	var (
+		value     = strconv.FormatFloat(d.value, 'f', -1, 64)
+		timestamp = strconv.FormatInt(d.timestamp, 10)
+	)
+	d.buffer.WriteString(nextPart)
+	d.buffer.WriteString(value)
+	d.buffer.WriteString(nextPart)
+	d.buffer.WriteString(timestamp)
+	d.buffer.WriteString(nextDatapoint)
+	return d.buffer.String()
+}

carbon/datapoint_test.go

@@ -0,0 +1,93 @@
+package carbon
+
+import "testing"
+
+func Test_NewDatapoint(t *testing.T) {
+	testCases := []struct {
+		actual   string
+		expected string
+	}{
+		{
+			actual:   NewDatapoint("metric1", 3.14159265359, 1552503600).String(),
+			expected: "metric1 3.14159265359 1552503600\n",
+		},
+		{
+			actual: NewDatapoint("metric1", 3.14159265359, 1552503600).
+				WithPrefix("foo").
+				String(),
+			expected: "foo.metric1 3.14159265359 1552503600\n",
+		},
+		{
+			actual: NewDatapoint("metric1", 3.14159265359, 1552503600).
+				WithPrefix("foo").
+				WithPrefix("bar").
+				String(),
+			expected: "bar.foo.metric1 3.14159265359 1552503600\n",
+		},
+		{
+			actual: NewDatapoint("metric1", 3.14159265359, 1552503600).
+				WithPrefix("foo").
+				WithPrefix("bar").
+				WithTag("cpu", "cpu1").
+				String(),
+			expected: "bar.foo.metric1;cpu=cpu1 3.14159265359 1552503600\n",
+		},
+		{
+			actual: NewDatapoint("metric1", 3.14159265359, 1552503600).
+				WithTag("cpu", "cpu1").
+				WithPrefix("foo").
+				WithPrefix("bar").
+				String(),
+			expected: "bar.foo.metric1;cpu=cpu1 3.14159265359 1552503600\n",
+		},
+		{
+			actual: NewDatapoint("metric1", 3.14159265359, 1552503600).
+				WithPrefix("foo").
+				WithPrefix("bar").
+				WithTag("cpu", "cpu1").
+				WithTag("dc", "dc1").
+				String(),
+			expected: "bar.foo.metric1;cpu=cpu1;dc=dc1 3.14159265359 1552503600\n",
+		},
+		{
+			actual: NewDatapoint("metric1", 3.14159265359, 1552503600).
+				WithTag("cpu", "cpu1").
+				WithTag("dc", "dc1").
+				WithPrefix("foo").
+				WithPrefix("bar").
+				String(),
+			expected: "bar.foo.metric1;cpu=cpu1;dc=dc1 3.14159265359 1552503600\n",
+		},
+	}
+
+	for _, testCase := range testCases {
+		if testCase.actual != testCase.expected {
+			t.Fatalf("expected: %s\nactual: %s", testCase.expected, testCase.actual)
+		}
+	}
+}
+
+func BenchmarkDatapoint_String(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		NewDatapoint("metric1", 3.14159265359, 1552503600).
+			WithPrefix("foo").
+			WithPrefix("bar").
+			WithTag("cpu", "cpu1").
+			WithTag("dc", "dc1").
+			WithTag("env", "stage").
+			WithTag("service", "exporter").
+			WithTag("version", "v0.0.1").
+			WithTag("git-commit", "0b1a09c").
+			String()
+	}
+}
+
+func BenchmarkDatapoint_StringByName(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		NewDatapoint(
+			"bar.foo.metric1;cpu=cpu1;dc=dc1;env=stage;service=exporter;version=v0.0.1;git-commit=0b1a09c",
+			3.14159265359,
+			1552503600).
+			String()
+	}
+}