forgejo/modules/setting/config_provider.go
wxiaoguang 6f9c278559
Rewrite queue (#24505)
# ⚠️ Breaking

Many deprecated queue config options are removed (actually, they should
have been removed in 1.18/1.19).

If you see the fatal message when starting Gitea: "Please update your
app.ini to remove deprecated config options", please follow the error
messages to remove these options from your app.ini.

Example:

```
2023/05/06 19:39:22 [E] Removed queue option: `[indexer].ISSUE_INDEXER_QUEUE_TYPE`. Use new options in `[queue.issue_indexer]`
2023/05/06 19:39:22 [E] Removed queue option: `[indexer].UPDATE_BUFFER_LEN`. Use new options in `[queue.issue_indexer]`
2023/05/06 19:39:22 [F] Please update your app.ini to remove deprecated config options
```

Many options in `[queue]` are are dropped, including:
`WRAP_IF_NECESSARY`, `MAX_ATTEMPTS`, `TIMEOUT`, `WORKERS`,
`BLOCK_TIMEOUT`, `BOOST_TIMEOUT`, `BOOST_WORKERS`, they can be removed
from app.ini.

# The problem

The old queue package has some legacy problems:

* complexity: I doubt few people could tell how it works.
* maintainability: Too many channels and mutex/cond are mixed together,
too many different structs/interfaces depends each other.
* stability: due to the complexity & maintainability, sometimes there
are strange bugs and difficult to debug, and some code doesn't have test
(indeed some code is difficult to test because a lot of things are mixed
together).
* general applicability: although it is called "queue", its behavior is
not a well-known queue.
* scalability: it doesn't seem easy to make it work with a cluster
without breaking its behaviors.

It came from some very old code to "avoid breaking", however, its
technical debt is too heavy now. It's a good time to introduce a better
"queue" package.

# The new queue package

It keeps using old config and concept as much as possible.

* It only contains two major kinds of concepts:
    * The "base queue": channel, levelqueue, redis
* They have the same abstraction, the same interface, and they are
tested by the same testing code.
* The "WokerPoolQueue", it uses the "base queue" to provide "worker
pool" function, calls the "handler" to process the data in the base
queue.
* The new code doesn't do "PushBack"
* Think about a queue with many workers, the "PushBack" can't guarantee
the order for re-queued unhandled items, so in new code it just does
"normal push"
* The new code doesn't do "pause/resume"
* The "pause/resume" was designed to handle some handler's failure: eg:
document indexer (elasticsearch) is down
* If a queue is paused for long time, either the producers blocks or the
new items are dropped.
* The new code doesn't do such "pause/resume" trick, it's not a common
queue's behavior and it doesn't help much.
* If there are unhandled items, the "push" function just blocks for a
few seconds and then re-queue them and retry.
* The new code doesn't do "worker booster"
* Gitea's queue's handlers are light functions, the cost is only the
go-routine, so it doesn't make sense to "boost" them.
* The new code only use "max worker number" to limit the concurrent
workers.
* The new "Push" never blocks forever
* Instead of creating more and more blocking goroutines, return an error
is more friendly to the server and to the end user.

There are more details in code comments: eg: the "Flush" problem, the
strange "code.index" hanging problem, the "immediate" queue problem.

Almost ready for review.

TODO:

* [x] add some necessary comments during review
* [x] add some more tests if necessary
* [x] update documents and config options
* [x] test max worker / active worker
* [x] re-run the CI tasks to see whether any test is flaky
* [x] improve the `handleOldLengthConfiguration` to provide more
friendly messages
* [x] fine tune default config values (eg: length?)

## Code coverage:

![image](https://user-images.githubusercontent.com/2114189/236620635-55576955-f95d-4810-b12f-879026a3afdf.png)
2023-05-08 19:49:59 +08:00

181 lines
5.2 KiB
Go

// Copyright 2023 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package setting
import (
"fmt"
"os"
"path/filepath"
"strings"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/util"
ini "gopkg.in/ini.v1"
)
type ConfigSection interface {
Name() string
MapTo(interface{}) error
HasKey(key string) bool
NewKey(name, value string) (*ini.Key, error)
Key(key string) *ini.Key
Keys() []*ini.Key
ChildSections() []*ini.Section
}
// ConfigProvider represents a config provider
type ConfigProvider interface {
Section(section string) ConfigSection
NewSection(name string) (ConfigSection, error)
GetSection(name string) (ConfigSection, error)
DeleteSection(name string) error
Save() error
}
type iniFileConfigProvider struct {
opts *Options
*ini.File
newFile bool // whether the file has not existed previously
}
// NewEmptyConfigProvider create a new empty config provider
func NewEmptyConfigProvider() ConfigProvider {
cp, _ := NewConfigProviderFromData("")
return cp
}
// NewConfigProviderFromData this function is only for testing
func NewConfigProviderFromData(configContent string) (ConfigProvider, error) {
var cfg *ini.File
var err error
if configContent == "" {
cfg = ini.Empty()
} else {
cfg, err = ini.Load(strings.NewReader(configContent))
if err != nil {
return nil, err
}
}
cfg.NameMapper = ini.SnackCase
return &iniFileConfigProvider{
File: cfg,
newFile: true,
}, nil
}
type Options struct {
CustomConf string // the ini file path
AllowEmpty bool // whether not finding configuration files is allowed (only true for the tests)
ExtraConfig string
DisableLoadCommonSettings bool
}
// newConfigProviderFromFile load configuration from file.
// NOTE: do not print any log except error.
func newConfigProviderFromFile(opts *Options) (*iniFileConfigProvider, error) {
cfg := ini.Empty()
newFile := true
if opts.CustomConf != "" {
isFile, err := util.IsFile(opts.CustomConf)
if err != nil {
return nil, fmt.Errorf("unable to check if %s is a file. Error: %v", opts.CustomConf, err)
}
if isFile {
if err := cfg.Append(opts.CustomConf); err != nil {
return nil, fmt.Errorf("failed to load custom conf '%s': %v", opts.CustomConf, err)
}
newFile = false
}
}
if newFile && !opts.AllowEmpty {
return nil, fmt.Errorf("unable to find configuration file: %q, please ensure you are running in the correct environment or set the correct configuration file with -c", CustomConf)
}
if opts.ExtraConfig != "" {
if err := cfg.Append([]byte(opts.ExtraConfig)); err != nil {
return nil, fmt.Errorf("unable to append more config: %v", err)
}
}
cfg.NameMapper = ini.SnackCase
return &iniFileConfigProvider{
opts: opts,
File: cfg,
newFile: newFile,
}, nil
}
func (p *iniFileConfigProvider) Section(section string) ConfigSection {
return p.File.Section(section)
}
func (p *iniFileConfigProvider) NewSection(name string) (ConfigSection, error) {
return p.File.NewSection(name)
}
func (p *iniFileConfigProvider) GetSection(name string) (ConfigSection, error) {
return p.File.GetSection(name)
}
func (p *iniFileConfigProvider) DeleteSection(name string) error {
p.File.DeleteSection(name)
return nil
}
// Save save the content into file
func (p *iniFileConfigProvider) Save() error {
if p.opts.CustomConf == "" {
if !p.opts.AllowEmpty {
return fmt.Errorf("custom config path must not be empty")
}
return nil
}
if p.newFile {
if err := os.MkdirAll(filepath.Dir(CustomConf), os.ModePerm); err != nil {
return fmt.Errorf("failed to create '%s': %v", CustomConf, err)
}
}
if err := p.SaveTo(p.opts.CustomConf); err != nil {
return fmt.Errorf("failed to save '%s': %v", p.opts.CustomConf, err)
}
// Change permissions to be more restrictive
fi, err := os.Stat(CustomConf)
if err != nil {
return fmt.Errorf("failed to determine current conf file permissions: %v", err)
}
if fi.Mode().Perm() > 0o600 {
if err = os.Chmod(CustomConf, 0o600); err != nil {
log.Warn("Failed changing conf file permissions to -rw-------. Consider changing them manually.")
}
}
return nil
}
// a file is an implementation ConfigProvider and other implementations are possible, i.e. from docker, k8s, …
var _ ConfigProvider = &iniFileConfigProvider{}
func mustMapSetting(rootCfg ConfigProvider, sectionName string, setting interface{}) {
if err := rootCfg.Section(sectionName).MapTo(setting); err != nil {
log.Fatal("Failed to map %s settings: %v", sectionName, err)
}
}
func deprecatedSetting(rootCfg ConfigProvider, oldSection, oldKey, newSection, newKey, version string) {
if rootCfg.Section(oldSection).HasKey(oldKey) {
log.Error("Deprecated fallback `[%s]` `%s` present. Use `[%s]` `%s` instead. This fallback will be/has been removed in %s", oldSection, oldKey, newSection, newKey, version)
}
}
// deprecatedSettingDB add a hint that the configuration has been moved to database but still kept in app.ini
func deprecatedSettingDB(rootCfg ConfigProvider, oldSection, oldKey string) {
if rootCfg.Section(oldSection).HasKey(oldKey) {
log.Error("Deprecated `[%s]` `%s` present which has been copied to database table sys_setting", oldSection, oldKey)
}
}