refactor: logparser v5 to pkgs

logparser/v5/pipe/record.go

@@ -0,0 +1,85 @@
+package pipe
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strconv"
+	"strings"
+)
+
+const fieldsLength = 4
+
+// Record stores fields of a log line.
+type Record struct {
+	Domain  string
+	Page    string
+	Visits  int
+	Uniques int
+}
+
+// Sum the numeric fields with another record.
+func (r Record) Sum(other Record) Record {
+	r.Visits += other.Visits
+	r.Uniques += other.Uniques
+	return r
+}
+
+// UnmarshalText to a *Record.
+func (r *Record) UnmarshalText(p []byte) (err error) {
+	fields := strings.Fields(string(p))
+	if len(fields) != fieldsLength {
+		return fmt.Errorf("wrong number of fields %q", fields)
+	}
+
+	r.Domain, r.Page = fields[0], fields[1]
+
+	if r.Visits, err = parseStr("visits", fields[2]); err != nil {
+		return err
+	}
+	if r.Uniques, err = parseStr("uniques", fields[3]); err != nil {
+		return err
+	}
+	return validate(*r)
+}
+
+// UnmarshalJSON to a *Record.
+func (r *Record) UnmarshalJSON(data []byte) error {
+	// `methodless` doesn't have any methods including UnmarshalJSON.
+	// This trick prevents the stack-overflow (infinite loop).
+	type methodless Record
+
+	var m methodless
+	if err := json.Unmarshal(data, &m); err != nil {
+		return err
+	}
+
+	// Cast back to the Record and save.
+	*r = Record(m)
+
+	return validate(*r)
+}
+
+// parseStr helps UnmarshalText for string to positive int parsing.
+func parseStr(name, v string) (int, error) {
+	n, err := strconv.Atoi(v)
+	if err != nil {
+		return 0, fmt.Errorf("Record.UnmarshalText %q: %v", name, err)
+	}
+	return n, nil
+}
+
+// validate whether a parsed record is valid or not.
+func validate(r Record) (err error) {
+	switch {
+	case r.Domain == "":
+		err = errors.New("record.domain cannot be empty")
+	case r.Page == "":
+		err = errors.New("record.page cannot be empty")
+	case r.Visits < 0:
+		err = errors.New("record.visits cannot be negative")
+	case r.Uniques < 0:
+		err = errors.New("record.uniques cannot be negative")
+	}
+	return
+}