Add Wavefront parser (#4402)

plugins/parsers/wavefront/element.go

@@ -0,0 +1,238 @@
+package wavefront
+
+import (
+	"errors"
+	"fmt"
+	"strconv"
+	"time"
+)
+
+var (
+	ErrEOF              = errors.New("EOF")
+	ErrInvalidTimestamp = errors.New("Invalid timestamp")
+)
+
+// Interface for parsing line elements.
+type ElementParser interface {
+	parse(p *PointParser, pt *Point) error
+}
+
+type NameParser struct{}
+type ValueParser struct{}
+type TimestampParser struct {
+	optional bool
+}
+type WhiteSpaceParser struct {
+	nextOptional bool
+}
+type TagParser struct{}
+type LoopedParser struct {
+	wrappedParser ElementParser
+	wsPaser       *WhiteSpaceParser
+}
+type LiteralParser struct {
+	literal string
+}
+
+func (ep *NameParser) parse(p *PointParser, pt *Point) error {
+	//Valid characters are: a-z, A-Z, 0-9, hyphen ("-"), underscore ("_"), dot (".").
+	// Forward slash ("/") and comma (",") are allowed if metricName is enclosed in double quotes.
+	name, err := parseLiteral(p)
+	if err != nil {
+		return err
+	}
+	pt.Name = name
+	return nil
+}
+
+func (ep *ValueParser) parse(p *PointParser, pt *Point) error {
+	tok, lit := p.scan()
+	if tok == EOF {
+		return fmt.Errorf("found %q, expected number", lit)
+	}
+
+	p.writeBuf.Reset()
+	if tok == MINUS_SIGN {
+		p.writeBuf.WriteString(lit)
+		tok, lit = p.scan()
+	}
+
+	for tok != EOF && (tok == LETTER || tok == NUMBER || tok == DOT) {
+		p.writeBuf.WriteString(lit)
+		tok, lit = p.scan()
+	}
+	p.unscan()
+
+	pt.Value = p.writeBuf.String()
+	_, err := strconv.ParseFloat(pt.Value, 64)
+	if err != nil {
+		return fmt.Errorf("invalid metric value %s", pt.Value)
+	}
+	return nil
+}
+
+func (ep *TimestampParser) parse(p *PointParser, pt *Point) error {
+	tok, lit := p.scan()
+	if tok == EOF {
+		if ep.optional {
+			p.unscanTokens(2)
+			return setTimestamp(pt, 0, 1)
+		}
+		return fmt.Errorf("found %q, expected number", lit)
+	}
+
+	if tok != NUMBER {
+		if ep.optional {
+			p.unscanTokens(2)
+			return setTimestamp(pt, 0, 1)
+		}
+		return ErrInvalidTimestamp
+	}
+
+	p.writeBuf.Reset()
+	for tok != EOF && tok == NUMBER {
+		p.writeBuf.WriteString(lit)
+		tok, lit = p.scan()
+	}
+	p.unscan()
+
+	tsStr := p.writeBuf.String()
+	ts, err := strconv.ParseInt(tsStr, 10, 64)
+	if err != nil {
+		return err
+	}
+	return setTimestamp(pt, ts, len(tsStr))
+}
+
+func setTimestamp(pt *Point, ts int64, numDigits int) error {
+
+	if numDigits == 19 {
+		// nanoseconds
+		ts = ts / 1e9
+	} else if numDigits == 16 {
+		// microseconds
+		ts = ts / 1e6
+	} else if numDigits == 13 {
+		// milliseconds
+		ts = ts / 1e3
+	} else if numDigits != 10 {
+		// must be in seconds, return error if not 0
+		if ts == 0 {
+			ts = getCurrentTime()
+		} else {
+			return ErrInvalidTimestamp
+		}
+	}
+	pt.Timestamp = ts
+	return nil
+}
+
+func (ep *LoopedParser) parse(p *PointParser, pt *Point) error {
+	for {
+		err := ep.wrappedParser.parse(p, pt)
+		if err != nil {
+			return err
+		}
+		err = ep.wsPaser.parse(p, pt)
+		if err == ErrEOF {
+			break
+		}
+	}
+	return nil
+}
+
+func (ep *TagParser) parse(p *PointParser, pt *Point) error {
+	k, err := parseLiteral(p)
+	if err != nil {
+		if k == "" {
+			return nil
+		}
+		return err
+	}
+
+	next, lit := p.scan()
+	if next != EQUALS {
+		return fmt.Errorf("found %q, expected equals", lit)
+	}
+
+	v, err := parseLiteral(p)
+	if err != nil {
+		return err
+	}
+	if len(pt.Tags) == 0 {
+		pt.Tags = make(map[string]string)
+	}
+	pt.Tags[k] = v
+	return nil
+}
+
+func (ep *WhiteSpaceParser) parse(p *PointParser, pt *Point) error {
+	tok := WS
+	for tok != EOF && tok == WS {
+		tok, _ = p.scan()
+	}
+
+	if tok == EOF {
+		if !ep.nextOptional {
+			return ErrEOF
+		}
+		return nil
+	}
+	p.unscan()
+	return nil
+}
+
+func (ep *LiteralParser) parse(p *PointParser, pt *Point) error {
+	l, err := parseLiteral(p)
+	if err != nil {
+		return err
+	}
+
+	if l != ep.literal {
+		return fmt.Errorf("found %s, expected %s", l, ep.literal)
+	}
+	return nil
+}
+
+func parseQuotedLiteral(p *PointParser) (string, error) {
+	p.writeBuf.Reset()
+
+	escaped := false
+	tok, lit := p.scan()
+	for tok != EOF && (tok != QUOTES || (tok == QUOTES && escaped)) {
+		// let everything through
+		escaped = tok == BACKSLASH
+		p.writeBuf.WriteString(lit)
+		tok, lit = p.scan()
+	}
+	if tok == EOF {
+		return "", fmt.Errorf("found %q, expected quotes", lit)
+	}
+	return p.writeBuf.String(), nil
+}
+
+func parseLiteral(p *PointParser) (string, error) {
+	tok, lit := p.scan()
+	if tok == EOF {
+		return "", fmt.Errorf("found %q, expected literal", lit)
+	}
+
+	if tok == QUOTES {
+		return parseQuotedLiteral(p)
+	}
+
+	p.writeBuf.Reset()
+	for tok != EOF && tok > literal_beg && tok < literal_end {
+		p.writeBuf.WriteString(lit)
+		tok, lit = p.scan()
+	}
+	if tok == QUOTES {
+		return "", errors.New("found quote inside unquoted literal")
+	}
+	p.unscan()
+	return p.writeBuf.String(), nil
+}
+
+func getCurrentTime() int64 {
+	return time.Now().UnixNano() / 1e9
+}