use strconf.FormatFloat instead of fmt.Sprintf for converting floats to...

use strconf.FormatFloat instead of fmt.Sprintf for converting floats to strings, this way we can eliminate non significant trailing zeros such that the float value 1 would be "1" as a string instead of "1.000000"

pkg/logentry/stages/util.go

@@ -85,9 +85,9 @@ func getString(unk interface{}) (string, error) {
 
 	switch i := unk.(type) {
 	case float64:
-		return fmt.Sprintf("%f", i), nil
+		return strconv.FormatFloat(i, 'f', -1, 64), nil
 	case float32:
-		return fmt.Sprintf("%f", i), nil
+		return strconv.FormatFloat(float64(i), 'f', -1, 32), nil
 	case int64:
 		return strconv.FormatInt(i, 10), nil
 	case int32:

pkg/logentry/stages/util_test.go

@@ -37,3 +37,31 @@ func assertLabels(t *testing.T, expect map[string]string, got model.LabelSet) {
 		assert.Equal(t, model.LabelValue(v), gotV, "mismatch label value")
 	}
 }
+
+// Verify the formatting of float conversion to make sure there are not any trailing zeros,
+// and also make sure unix timestamps are converted properly
+func TestGetString(t *testing.T) {
+	var f64, f64_1 float64
+	var f32 float32
+	f64 = 1
+	f64_1 = 1562723913000
+	f32 = 2.02
+	s64, err := getString(f64)
+	if err != nil {
+		t.Errorf("Failed to get string from float... this shouldn't have happened: %v", err)
+		return
+	}
+	s64_1, err := getString(f64_1)
+	if err != nil {
+		t.Errorf("Failed to get string from float... this shouldn't have happened: %v", err)
+		return
+	}
+	s32, err := getString(f32)
+	if err != nil {
+		t.Errorf("Failed to get string from float... this shouldn't have happened: %v", err)
+		return
+	}
+	assert.Equal(t, "1", s64)
+	assert.Equal(t, "2.02", s32)
+	assert.Equal(t, "1562723913000", s64_1)
+}