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|
package mapr
import (
"errors"
"fmt"
"strconv"
"strings"
"time"
"github.com/mimecast/dtail/internal/io/logger"
)
const (
invalidQuery string = "Invalid query: "
unexpectedEnd string = "Unexpected end of query"
)
// Query represents a parsed mapr query.
type Query struct {
Select []selectCondition
Table string
Where []whereCondition
Set []setCondition
GroupBy []string
OrderBy string
ReverseOrder bool
GroupKey string
Interval time.Duration
Limit int
Outfile string
RawQuery string
tokens []token
LogFormat string
}
func (q Query) String() string {
return fmt.Sprintf("Query(Select:%v,Table:%s,Where:%v,Set:%vGroupBy:%v,GroupKey:%s,OrderBy:%v,ReverseOrder:%v,Interval:%v,Limit:%d,Outfile:%s,RawQuery:%s,tokens:%v,LogFormat:%s)",
q.Select,
q.Table,
q.Where,
q.Set,
q.GroupBy,
q.GroupKey,
q.OrderBy,
q.ReverseOrder,
q.Interval,
q.Limit,
q.Outfile,
q.RawQuery,
q.tokens,
q.LogFormat)
}
// NewQuery returns a new mapreduce query.
func NewQuery(queryStr string) (*Query, error) {
if queryStr == "" {
return nil, nil
}
tokens := tokenize(queryStr)
q := Query{
RawQuery: queryStr,
tokens: tokens,
Interval: time.Second * 5,
Limit: -1,
}
err := q.parse(tokens)
logger.Debug(q)
return &q, err
}
// HasOutfile returns true if query result will be written to a CVS output file.
func (q *Query) HasOutfile() bool {
return q.Outfile != ""
}
// Has is a helper to determine whether a query contains a substring
func (q *Query) Has(what string) bool {
return strings.Contains(q.RawQuery, what)
}
func (q *Query) parse(tokens []token) error {
var found []token
var err error
for tokens != nil && len(tokens) > 0 {
switch strings.ToLower(tokens[0].str) {
case "select":
tokens, found = tokensConsume(tokens[1:])
q.Select, err = makeSelectConditions(found)
if err != nil {
return err
}
case "from":
tokens, found = tokensConsume(tokens[1:])
if len(found) == 0 {
return errors.New(invalidQuery + "expected table name after 'from'")
}
if len(found) > 1 {
return errors.New(invalidQuery + "expected only one table name after 'from'")
}
q.Table = strings.ToUpper(found[0].str)
case "where":
tokens, found = tokensConsume(tokens[1:])
if q.Where, err = makeWhereConditions(found); err != nil {
return err
}
case "set":
tokens, found = tokensConsume(tokens[1:])
if q.Set, err = makeSetConditions(found); err != nil {
return err
}
case "group":
tokens = tokensConsumeOptional(tokens[1:], "by")
if tokens == nil || len(tokens) < 1 {
return errors.New(invalidQuery + unexpectedEnd)
}
tokens, q.GroupBy = tokensConsumeStr(tokens)
q.GroupKey = strings.Join(q.GroupBy, ",")
case "rorder":
tokens = tokensConsumeOptional(tokens[1:], "by")
if tokens == nil || len(tokens) < 1 {
return errors.New(invalidQuery + unexpectedEnd)
}
tokens, found = tokensConsume(tokens)
if len(found) == 0 {
return errors.New(invalidQuery + unexpectedEnd)
}
q.OrderBy = found[0].str
q.ReverseOrder = true
case "order":
tokens = tokensConsumeOptional(tokens[1:], "by")
if tokens == nil || len(tokens) < 1 {
return errors.New(invalidQuery + unexpectedEnd)
}
tokens, found = tokensConsume(tokens)
if len(found) == 0 {
return errors.New(invalidQuery + unexpectedEnd)
}
q.OrderBy = found[0].str
case "interval":
tokens, found = tokensConsume(tokens[1:])
if len(found) > 0 {
i, err := strconv.Atoi(found[0].str)
if err != nil {
return errors.New(invalidQuery + err.Error())
}
q.Interval = time.Second * time.Duration(i)
}
case "limit":
tokens, found = tokensConsume(tokens[1:])
if len(found) == 0 {
return errors.New(invalidQuery + unexpectedEnd)
}
i, err := strconv.Atoi(found[0].str)
if err != nil {
return errors.New(invalidQuery + err.Error())
}
q.Limit = i
case "outfile":
tokens, found = tokensConsume(tokens[1:])
if len(found) == 0 {
return errors.New(invalidQuery + unexpectedEnd)
}
q.Outfile = found[0].str
case "logformat":
tokens, found = tokensConsume(tokens[1:])
if len(found) == 0 {
return errors.New(invalidQuery + unexpectedEnd)
}
q.LogFormat = found[0].str
default:
return errors.New(invalidQuery + "Unexpected keyword " + tokens[0].str)
}
}
if len(q.Select) < 1 {
return errors.New(invalidQuery + "Expected at least one field in 'select' clause but got none")
}
if len(q.GroupBy) == 0 {
field := q.Select[0].Field
q.GroupBy = append(q.GroupBy, field)
}
if q.OrderBy != "" {
var orderFieldIsValid bool
for _, sc := range q.Select {
if q.OrderBy == sc.FieldStorage {
orderFieldIsValid = true
break
}
}
if !orderFieldIsValid {
return errors.New(invalidQuery + fmt.Sprintf("Can not '(r)order by' '%s', must be present in 'select' clause", q.OrderBy))
}
}
return nil
}
|
