This is a new revision of the discovery server. Relevant changes and non-changes: - Protocol towards clients is unchanged. - Recommended large scale design is still to be deployed nehind nginx (I tested, and it's still a lot faster at terminating TLS). - Database backend is leveldb again, only. It scales enough, is easy to setup, and we don't need any backend to take care of. - Server supports replication. This is a simple TCP channel - protect it with a firewall when deploying over the internet. (We deploy this within the same datacenter, and with firewall.) Any incoming client announces are sent over the replication channel(s) to other peer discosrvs. Incoming replication changes are applied to the database as if they came from clients, but without the TLS/certificate overhead. - Metrics are exposed using the prometheus library, when enabled. - The database values and replication protocol is protobuf, because JSON was quite CPU intensive when I tried that and benchmarked it. - The "Retry-After" value for failed lookups gets slowly increased from a default of 120 seconds, by 5 seconds for each failed lookup, independently by each discosrv. This lowers the query load over time for clients that are never seen. The Retry-After maxes out at 3600 after a couple of weeks of this increase. The number of failed lookups is stored in the database, now and then (avoiding making each lookup a database put). All in all this means clients can be pointed towards a cluster using just multiple A / AAAA records to gain both load sharing and redundancy (if one is down, clients will talk to the remaining ones). GitHub-Pull-Request: https://github.com/syncthing/syncthing/pull/4648
402 lines
9.3 KiB
Go
402 lines
9.3 KiB
Go
// Copyright 2015 Unknwon
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//
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// Licensed under the Apache License, Version 2.0 (the "License"): you may
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// not use this file except in compliance with the License. You may obtain
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// a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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// WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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// License for the specific language governing permissions and limitations
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// under the License.
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package ini
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import (
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"bufio"
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"bytes"
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"fmt"
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"io"
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"strconv"
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"strings"
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"unicode"
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)
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type tokenType int
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const (
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_TOKEN_INVALID tokenType = iota
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_TOKEN_COMMENT
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_TOKEN_SECTION
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_TOKEN_KEY
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)
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type parser struct {
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buf *bufio.Reader
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isEOF bool
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count int
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comment *bytes.Buffer
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}
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func newParser(r io.Reader) *parser {
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return &parser{
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buf: bufio.NewReader(r),
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count: 1,
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comment: &bytes.Buffer{},
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}
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}
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// BOM handles header of UTF-8, UTF-16 LE and UTF-16 BE's BOM format.
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// http://en.wikipedia.org/wiki/Byte_order_mark#Representations_of_byte_order_marks_by_encoding
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func (p *parser) BOM() error {
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mask, err := p.buf.Peek(2)
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if err != nil && err != io.EOF {
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return err
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} else if len(mask) < 2 {
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return nil
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}
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switch {
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case mask[0] == 254 && mask[1] == 255:
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fallthrough
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case mask[0] == 255 && mask[1] == 254:
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p.buf.Read(mask)
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case mask[0] == 239 && mask[1] == 187:
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mask, err := p.buf.Peek(3)
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if err != nil && err != io.EOF {
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return err
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} else if len(mask) < 3 {
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return nil
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}
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if mask[2] == 191 {
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p.buf.Read(mask)
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}
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}
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return nil
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}
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func (p *parser) readUntil(delim byte) ([]byte, error) {
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data, err := p.buf.ReadBytes(delim)
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if err != nil {
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if err == io.EOF {
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p.isEOF = true
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} else {
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return nil, err
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}
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}
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return data, nil
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}
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func cleanComment(in []byte) ([]byte, bool) {
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i := bytes.IndexAny(in, "#;")
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if i == -1 {
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return nil, false
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}
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return in[i:], true
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}
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func readKeyName(in []byte) (string, int, error) {
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line := string(in)
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// Check if key name surrounded by quotes.
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var keyQuote string
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if line[0] == '"' {
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if len(line) > 6 && string(line[0:3]) == `"""` {
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keyQuote = `"""`
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} else {
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keyQuote = `"`
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}
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} else if line[0] == '`' {
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keyQuote = "`"
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}
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// Get out key name
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endIdx := -1
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if len(keyQuote) > 0 {
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startIdx := len(keyQuote)
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// FIXME: fail case -> """"""name"""=value
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pos := strings.Index(line[startIdx:], keyQuote)
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if pos == -1 {
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return "", -1, fmt.Errorf("missing closing key quote: %s", line)
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}
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pos += startIdx
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// Find key-value delimiter
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i := strings.IndexAny(line[pos+startIdx:], "=:")
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if i < 0 {
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return "", -1, ErrDelimiterNotFound{line}
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}
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endIdx = pos + i
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return strings.TrimSpace(line[startIdx:pos]), endIdx + startIdx + 1, nil
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}
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endIdx = strings.IndexAny(line, "=:")
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if endIdx < 0 {
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return "", -1, ErrDelimiterNotFound{line}
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}
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return strings.TrimSpace(line[0:endIdx]), endIdx + 1, nil
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}
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func (p *parser) readMultilines(line, val, valQuote string) (string, error) {
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for {
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data, err := p.readUntil('\n')
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if err != nil {
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return "", err
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}
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next := string(data)
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pos := strings.LastIndex(next, valQuote)
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if pos > -1 {
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val += next[:pos]
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comment, has := cleanComment([]byte(next[pos:]))
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if has {
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p.comment.Write(bytes.TrimSpace(comment))
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}
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break
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}
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val += next
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if p.isEOF {
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return "", fmt.Errorf("missing closing key quote from '%s' to '%s'", line, next)
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}
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}
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return val, nil
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}
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func (p *parser) readContinuationLines(val string) (string, error) {
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for {
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data, err := p.readUntil('\n')
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if err != nil {
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return "", err
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}
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next := strings.TrimSpace(string(data))
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if len(next) == 0 {
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break
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}
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val += next
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if val[len(val)-1] != '\\' {
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break
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}
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val = val[:len(val)-1]
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}
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return val, nil
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}
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// hasSurroundedQuote check if and only if the first and last characters
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// are quotes \" or \'.
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// It returns false if any other parts also contain same kind of quotes.
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func hasSurroundedQuote(in string, quote byte) bool {
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return len(in) >= 2 && in[0] == quote && in[len(in)-1] == quote &&
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strings.IndexByte(in[1:], quote) == len(in)-2
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}
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func (p *parser) readValue(in []byte,
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ignoreContinuation, ignoreInlineComment, unescapeValueDoubleQuotes, unescapeValueCommentSymbols bool) (string, error) {
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line := strings.TrimLeftFunc(string(in), unicode.IsSpace)
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if len(line) == 0 {
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return "", nil
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}
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var valQuote string
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if len(line) > 3 && string(line[0:3]) == `"""` {
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valQuote = `"""`
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} else if line[0] == '`' {
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valQuote = "`"
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} else if unescapeValueDoubleQuotes && line[0] == '"' {
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valQuote = `"`
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}
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if len(valQuote) > 0 {
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startIdx := len(valQuote)
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pos := strings.LastIndex(line[startIdx:], valQuote)
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// Check for multi-line value
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if pos == -1 {
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return p.readMultilines(line, line[startIdx:], valQuote)
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}
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if unescapeValueDoubleQuotes && valQuote == `"` {
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return strings.Replace(line[startIdx:pos+startIdx], `\"`, `"`, -1), nil
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}
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return line[startIdx : pos+startIdx], nil
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}
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// Won't be able to reach here if value only contains whitespace
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line = strings.TrimSpace(line)
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// Check continuation lines when desired
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if !ignoreContinuation && line[len(line)-1] == '\\' {
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return p.readContinuationLines(line[:len(line)-1])
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}
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// Check if ignore inline comment
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if !ignoreInlineComment {
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i := strings.IndexAny(line, "#;")
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if i > -1 {
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p.comment.WriteString(line[i:])
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line = strings.TrimSpace(line[:i])
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}
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}
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// Trim single and double quotes
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if hasSurroundedQuote(line, '\'') ||
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hasSurroundedQuote(line, '"') {
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line = line[1 : len(line)-1]
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} else if len(valQuote) == 0 && unescapeValueCommentSymbols {
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if strings.Contains(line, `\;`) {
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line = strings.Replace(line, `\;`, ";", -1)
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}
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if strings.Contains(line, `\#`) {
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line = strings.Replace(line, `\#`, "#", -1)
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}
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}
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return line, nil
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}
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// parse parses data through an io.Reader.
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func (f *File) parse(reader io.Reader) (err error) {
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p := newParser(reader)
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if err = p.BOM(); err != nil {
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return fmt.Errorf("BOM: %v", err)
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}
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// Ignore error because default section name is never empty string.
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name := DEFAULT_SECTION
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if f.options.Insensitive {
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name = strings.ToLower(DEFAULT_SECTION)
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}
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section, _ := f.NewSection(name)
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// This "last" is not strictly equivalent to "previous one" if current key is not the first nested key
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var isLastValueEmpty bool
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var lastRegularKey *Key
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var line []byte
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var inUnparseableSection bool
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for !p.isEOF {
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line, err = p.readUntil('\n')
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if err != nil {
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return err
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}
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if f.options.AllowNestedValues &&
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isLastValueEmpty && len(line) > 0 {
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if line[0] == ' ' || line[0] == '\t' {
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lastRegularKey.addNestedValue(string(bytes.TrimSpace(line)))
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continue
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}
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}
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line = bytes.TrimLeftFunc(line, unicode.IsSpace)
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if len(line) == 0 {
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continue
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}
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// Comments
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if line[0] == '#' || line[0] == ';' {
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// Note: we do not care ending line break,
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// it is needed for adding second line,
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// so just clean it once at the end when set to value.
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p.comment.Write(line)
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continue
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}
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// Section
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if line[0] == '[' {
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// Read to the next ']' (TODO: support quoted strings)
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// TODO(unknwon): use LastIndexByte when stop supporting Go1.4
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closeIdx := bytes.LastIndex(line, []byte("]"))
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if closeIdx == -1 {
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return fmt.Errorf("unclosed section: %s", line)
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}
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name := string(line[1:closeIdx])
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section, err = f.NewSection(name)
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if err != nil {
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return err
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}
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comment, has := cleanComment(line[closeIdx+1:])
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if has {
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p.comment.Write(comment)
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}
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section.Comment = strings.TrimSpace(p.comment.String())
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// Reset aotu-counter and comments
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p.comment.Reset()
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p.count = 1
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inUnparseableSection = false
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for i := range f.options.UnparseableSections {
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if f.options.UnparseableSections[i] == name ||
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(f.options.Insensitive && strings.ToLower(f.options.UnparseableSections[i]) == strings.ToLower(name)) {
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inUnparseableSection = true
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continue
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}
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}
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continue
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}
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if inUnparseableSection {
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section.isRawSection = true
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section.rawBody += string(line)
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continue
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}
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kname, offset, err := readKeyName(line)
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if err != nil {
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// Treat as boolean key when desired, and whole line is key name.
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if IsErrDelimiterNotFound(err) && f.options.AllowBooleanKeys {
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kname, err := p.readValue(line,
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f.options.IgnoreContinuation,
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f.options.IgnoreInlineComment,
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f.options.UnescapeValueDoubleQuotes,
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f.options.UnescapeValueCommentSymbols)
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if err != nil {
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return err
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}
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key, err := section.NewBooleanKey(kname)
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if err != nil {
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return err
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}
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key.Comment = strings.TrimSpace(p.comment.String())
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p.comment.Reset()
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continue
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}
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return err
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}
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// Auto increment.
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isAutoIncr := false
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if kname == "-" {
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isAutoIncr = true
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kname = "#" + strconv.Itoa(p.count)
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p.count++
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}
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value, err := p.readValue(line[offset:],
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f.options.IgnoreContinuation,
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f.options.IgnoreInlineComment,
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f.options.UnescapeValueDoubleQuotes,
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f.options.UnescapeValueCommentSymbols)
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if err != nil {
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return err
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}
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isLastValueEmpty = len(value) == 0
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key, err := section.NewKey(kname, value)
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if err != nil {
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return err
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}
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key.isAutoIncrement = isAutoIncr
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key.Comment = strings.TrimSpace(p.comment.String())
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p.comment.Reset()
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lastRegularKey = key
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}
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return nil
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}
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