Add human-readbale log output (#681)

Add human-readable log output. It prints out the exact source code line information.

formatter/formatter_test.go

@@ -0,0 +1,27 @@
+package formatter
+
+import (
+	"testing"
+	"time"
+
+	"github.com/sirupsen/logrus"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestLogMessageFormat(t *testing.T) {
+
+	someEntry := &logrus.Entry{
+		Data:    logrus.Fields{"att1": 1, "att2": 2, "source": "some/fancy/path.go:46"},
+		Time:    time.Date(2021, time.Month(2), 21, 1, 10, 30, 0, time.UTC),
+		Level:   3,
+		Message: "Some Message",
+	}
+
+	formatter := NewTextFormatter()
+	result, _ := formatter.Format(someEntry)
+
+	expectedString := "2021-02-21T01:10:30Z WARN [att1: 1, att2: 2] some/fancy/path.go:46: Some Message\n"
+	parsedString := string(result)
+	assert.Equal(t, expectedString, parsedString, "The log messages don't match.")
+
+}