Files
learngo/logparser/v5/pipe/parse/record.go
2019-08-28 20:23:38 +03:00

117 lines
2.4 KiB
Go

package parse
import (
"encoding/json"
"errors"
"fmt"
"strconv"
"strings"
"github.com/inancgumus/learngo/logparser/v5/pipe"
)
const fieldsLength = 4
// record stores fields of a log line.
type record struct {
Domain string
Page string
Visits int
Uniques int
}
// Str gets a string field by name.
func (r record) Str(field string) string {
switch field {
case "domain":
return r.Domain
case "page":
return r.Page
}
panic(fieldErr(field))
}
// Int gets an integer field by name.
func (r record) Int(field string) int {
switch field {
case "visits":
return r.Visits
case "uniques":
return r.Uniques
}
panic(fieldErr(field))
}
// Sum the numeric fields with another record.
func (r record) Sum(other pipe.Record) pipe.Record {
if other == nil {
return r
}
r.Visits += other.(record).Visits
r.Uniques += other.(record).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
}
func fieldErr(field string) error {
return fmt.Errorf("record field: %q does not exist", field)
}