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
399 lines
9.6 KiB
Go
399 lines
9.6 KiB
Go
// Copyright 2017 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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"bytes"
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"errors"
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"fmt"
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"io"
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"io/ioutil"
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"os"
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"strings"
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"sync"
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)
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// File represents a combination of a or more INI file(s) in memory.
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type File struct {
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options LoadOptions
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dataSources []dataSource
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// Should make things safe, but sometimes doesn't matter.
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BlockMode bool
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lock sync.RWMutex
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// To keep data in order.
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sectionList []string
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// Actual data is stored here.
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sections map[string]*Section
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NameMapper
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ValueMapper
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}
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// newFile initializes File object with given data sources.
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func newFile(dataSources []dataSource, opts LoadOptions) *File {
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return &File{
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BlockMode: true,
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dataSources: dataSources,
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sections: make(map[string]*Section),
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sectionList: make([]string, 0, 10),
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options: opts,
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}
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}
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// Empty returns an empty file object.
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func Empty() *File {
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// Ignore error here, we sure our data is good.
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f, _ := Load([]byte(""))
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return f
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}
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// NewSection creates a new section.
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func (f *File) NewSection(name string) (*Section, error) {
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if len(name) == 0 {
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return nil, errors.New("error creating new section: empty section name")
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} else if f.options.Insensitive && name != DEFAULT_SECTION {
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name = strings.ToLower(name)
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}
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if f.BlockMode {
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f.lock.Lock()
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defer f.lock.Unlock()
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}
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if inSlice(name, f.sectionList) {
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return f.sections[name], nil
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}
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f.sectionList = append(f.sectionList, name)
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f.sections[name] = newSection(f, name)
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return f.sections[name], nil
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}
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// NewRawSection creates a new section with an unparseable body.
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func (f *File) NewRawSection(name, body string) (*Section, error) {
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section, err := f.NewSection(name)
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if err != nil {
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return nil, err
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}
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section.isRawSection = true
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section.rawBody = body
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return section, nil
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}
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// NewSections creates a list of sections.
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func (f *File) NewSections(names ...string) (err error) {
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for _, name := range names {
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if _, err = f.NewSection(name); err != nil {
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return err
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}
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}
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return nil
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}
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// GetSection returns section by given name.
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func (f *File) GetSection(name string) (*Section, error) {
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if len(name) == 0 {
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name = DEFAULT_SECTION
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}
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if f.options.Insensitive {
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name = strings.ToLower(name)
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}
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if f.BlockMode {
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f.lock.RLock()
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defer f.lock.RUnlock()
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}
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sec := f.sections[name]
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if sec == nil {
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return nil, fmt.Errorf("section '%s' does not exist", name)
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}
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return sec, nil
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}
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// Section assumes named section exists and returns a zero-value when not.
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func (f *File) Section(name string) *Section {
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sec, err := f.GetSection(name)
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if err != nil {
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// Note: It's OK here because the only possible error is empty section name,
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// but if it's empty, this piece of code won't be executed.
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sec, _ = f.NewSection(name)
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return sec
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}
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return sec
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}
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// Section returns list of Section.
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func (f *File) Sections() []*Section {
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sections := make([]*Section, len(f.sectionList))
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for i := range f.sectionList {
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sections[i] = f.Section(f.sectionList[i])
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}
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return sections
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}
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// ChildSections returns a list of child sections of given section name.
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func (f *File) ChildSections(name string) []*Section {
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return f.Section(name).ChildSections()
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}
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// SectionStrings returns list of section names.
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func (f *File) SectionStrings() []string {
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list := make([]string, len(f.sectionList))
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copy(list, f.sectionList)
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return list
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}
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// DeleteSection deletes a section.
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func (f *File) DeleteSection(name string) {
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if f.BlockMode {
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f.lock.Lock()
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defer f.lock.Unlock()
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}
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if len(name) == 0 {
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name = DEFAULT_SECTION
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}
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for i, s := range f.sectionList {
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if s == name {
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f.sectionList = append(f.sectionList[:i], f.sectionList[i+1:]...)
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delete(f.sections, name)
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return
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}
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}
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}
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func (f *File) reload(s dataSource) error {
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r, err := s.ReadCloser()
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if err != nil {
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return err
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}
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defer r.Close()
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return f.parse(r)
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}
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// Reload reloads and parses all data sources.
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func (f *File) Reload() (err error) {
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for _, s := range f.dataSources {
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if err = f.reload(s); err != nil {
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// In loose mode, we create an empty default section for nonexistent files.
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if os.IsNotExist(err) && f.options.Loose {
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f.parse(bytes.NewBuffer(nil))
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continue
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}
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return err
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}
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}
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return nil
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}
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// Append appends one or more data sources and reloads automatically.
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func (f *File) Append(source interface{}, others ...interface{}) error {
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ds, err := parseDataSource(source)
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if err != nil {
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return err
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}
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f.dataSources = append(f.dataSources, ds)
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for _, s := range others {
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ds, err = parseDataSource(s)
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if err != nil {
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return err
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}
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f.dataSources = append(f.dataSources, ds)
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}
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return f.Reload()
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}
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func (f *File) writeToBuffer(indent string) (*bytes.Buffer, error) {
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equalSign := "="
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if PrettyFormat {
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equalSign = " = "
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}
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// Use buffer to make sure target is safe until finish encoding.
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buf := bytes.NewBuffer(nil)
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for i, sname := range f.sectionList {
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sec := f.Section(sname)
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if len(sec.Comment) > 0 {
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if sec.Comment[0] != '#' && sec.Comment[0] != ';' {
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sec.Comment = "; " + sec.Comment
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} else {
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sec.Comment = sec.Comment[:1] + " " + strings.TrimSpace(sec.Comment[1:])
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}
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if _, err := buf.WriteString(sec.Comment + LineBreak); err != nil {
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return nil, err
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}
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}
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if i > 0 || DefaultHeader {
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if _, err := buf.WriteString("[" + sname + "]" + LineBreak); err != nil {
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return nil, err
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}
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} else {
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// Write nothing if default section is empty
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if len(sec.keyList) == 0 {
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continue
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}
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}
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if sec.isRawSection {
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if _, err := buf.WriteString(sec.rawBody); err != nil {
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return nil, err
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}
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if PrettySection {
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// Put a line between sections
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if _, err := buf.WriteString(LineBreak); err != nil {
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return nil, err
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}
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}
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continue
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}
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// Count and generate alignment length and buffer spaces using the
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// longest key. Keys may be modifed if they contain certain characters so
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// we need to take that into account in our calculation.
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alignLength := 0
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if PrettyFormat {
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for _, kname := range sec.keyList {
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keyLength := len(kname)
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// First case will surround key by ` and second by """
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if strings.ContainsAny(kname, "\"=:") {
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keyLength += 2
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} else if strings.Contains(kname, "`") {
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keyLength += 6
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}
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if keyLength > alignLength {
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alignLength = keyLength
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}
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}
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}
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alignSpaces := bytes.Repeat([]byte(" "), alignLength)
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KEY_LIST:
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for _, kname := range sec.keyList {
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key := sec.Key(kname)
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if len(key.Comment) > 0 {
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if len(indent) > 0 && sname != DEFAULT_SECTION {
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buf.WriteString(indent)
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}
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if key.Comment[0] != '#' && key.Comment[0] != ';' {
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key.Comment = "; " + key.Comment
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} else {
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key.Comment = key.Comment[:1] + " " + strings.TrimSpace(key.Comment[1:])
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}
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if _, err := buf.WriteString(key.Comment + LineBreak); err != nil {
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return nil, err
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}
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}
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if len(indent) > 0 && sname != DEFAULT_SECTION {
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buf.WriteString(indent)
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}
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switch {
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case key.isAutoIncrement:
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kname = "-"
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case strings.ContainsAny(kname, "\"=:"):
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kname = "`" + kname + "`"
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case strings.Contains(kname, "`"):
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kname = `"""` + kname + `"""`
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}
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for _, val := range key.ValueWithShadows() {
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if _, err := buf.WriteString(kname); err != nil {
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return nil, err
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}
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if key.isBooleanType {
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if kname != sec.keyList[len(sec.keyList)-1] {
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buf.WriteString(LineBreak)
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}
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continue KEY_LIST
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}
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// Write out alignment spaces before "=" sign
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if PrettyFormat {
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buf.Write(alignSpaces[:alignLength-len(kname)])
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}
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// In case key value contains "\n", "`", "\"", "#" or ";"
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if strings.ContainsAny(val, "\n`") {
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val = `"""` + val + `"""`
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} else if !f.options.IgnoreInlineComment && strings.ContainsAny(val, "#;") {
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val = "`" + val + "`"
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}
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if _, err := buf.WriteString(equalSign + val + LineBreak); err != nil {
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return nil, err
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}
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}
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for _, val := range key.nestedValues {
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if _, err := buf.WriteString(indent + " " + val + LineBreak); err != nil {
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return nil, err
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}
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}
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}
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if PrettySection {
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// Put a line between sections
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if _, err := buf.WriteString(LineBreak); err != nil {
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return nil, err
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}
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}
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}
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return buf, nil
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}
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// WriteToIndent writes content into io.Writer with given indention.
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// If PrettyFormat has been set to be true,
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// it will align "=" sign with spaces under each section.
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func (f *File) WriteToIndent(w io.Writer, indent string) (int64, error) {
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buf, err := f.writeToBuffer(indent)
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if err != nil {
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return 0, err
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}
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return buf.WriteTo(w)
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}
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// WriteTo writes file content into io.Writer.
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func (f *File) WriteTo(w io.Writer) (int64, error) {
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return f.WriteToIndent(w, "")
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}
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// SaveToIndent writes content to file system with given value indention.
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func (f *File) SaveToIndent(filename, indent string) error {
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// Note: Because we are truncating with os.Create,
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// so it's safer to save to a temporary file location and rename afte done.
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buf, err := f.writeToBuffer(indent)
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if err != nil {
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return err
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}
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return ioutil.WriteFile(filename, buf.Bytes(), 0666)
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}
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// SaveTo writes content to file system.
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func (f *File) SaveTo(filename string) error {
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return f.SaveToIndent(filename, "")
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}
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