forgejo/modules/repository/commits.go
Lunny Xiao bd820aa9c5
Add context cache as a request level cache (#22294)
To avoid duplicated load of the same data in an HTTP request, we can set
a context cache to do that. i.e. Some pages may load a user from a
database with the same id in different areas on the same page. But the
code is hidden in two different deep logic. How should we share the
user? As a result of this PR, now if both entry functions accept
`context.Context` as the first parameter and we just need to refactor
`GetUserByID` to reuse the user from the context cache. Then it will not
be loaded twice on an HTTP request.

But of course, sometimes we would like to reload an object from the
database, that's why `RemoveContextData` is also exposed.

The core context cache is here. It defines a new context
```go
type cacheContext struct {
	ctx  context.Context
	data map[any]map[any]any
        lock sync.RWMutex
}

var cacheContextKey = struct{}{}

func WithCacheContext(ctx context.Context) context.Context {
	return context.WithValue(ctx, cacheContextKey, &cacheContext{
		ctx:  ctx,
		data: make(map[any]map[any]any),
	})
}
```

Then you can use the below 4 methods to read/write/del the data within
the same context.

```go
func GetContextData(ctx context.Context, tp, key any) any
func SetContextData(ctx context.Context, tp, key, value any)
func RemoveContextData(ctx context.Context, tp, key any)
func GetWithContextCache[T any](ctx context.Context, cacheGroupKey string, cacheTargetID any, f func() (T, error)) (T, error)
```

Then let's take a look at how `system.GetString` implement it.

```go
func GetSetting(ctx context.Context, key string) (string, error) {
	return cache.GetWithContextCache(ctx, contextCacheKey, key, func() (string, error) {
		return cache.GetString(genSettingCacheKey(key), func() (string, error) {
			res, err := GetSettingNoCache(ctx, key)
			if err != nil {
				return "", err
			}
			return res.SettingValue, nil
		})
	})
}
```

First, it will check if context data include the setting object with the
key. If not, it will query from the global cache which may be memory or
a Redis cache. If not, it will get the object from the database. In the
end, if the object gets from the global cache or database, it will be
set into the context cache.

An object stored in the context cache will only be destroyed after the
context disappeared.
2023-02-15 21:37:34 +08:00

195 lines
5.4 KiB
Go

// Copyright 2019 The Gitea Authors. All rights reserved.
// SPDX-License-Identifier: MIT
package repository
import (
"context"
"fmt"
"net/url"
"time"
"code.gitea.io/gitea/models/avatars"
user_model "code.gitea.io/gitea/models/user"
"code.gitea.io/gitea/modules/git"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/setting"
api "code.gitea.io/gitea/modules/structs"
)
// PushCommit represents a commit in a push operation.
type PushCommit struct {
Sha1 string
Message string
AuthorEmail string
AuthorName string
CommitterEmail string
CommitterName string
Timestamp time.Time
}
// PushCommits represents list of commits in a push operation.
type PushCommits struct {
Commits []*PushCommit
HeadCommit *PushCommit
CompareURL string
Len int
avatars map[string]string
emailUsers map[string]*user_model.User
}
// NewPushCommits creates a new PushCommits object.
func NewPushCommits() *PushCommits {
return &PushCommits{
avatars: make(map[string]string),
emailUsers: make(map[string]*user_model.User),
}
}
// toAPIPayloadCommit converts a single PushCommit to an api.PayloadCommit object.
func (pc *PushCommits) toAPIPayloadCommit(ctx context.Context, repoPath, repoLink string, commit *PushCommit) (*api.PayloadCommit, error) {
var err error
authorUsername := ""
author, ok := pc.emailUsers[commit.AuthorEmail]
if !ok {
author, err = user_model.GetUserByEmail(ctx, commit.AuthorEmail)
if err == nil {
authorUsername = author.Name
pc.emailUsers[commit.AuthorEmail] = author
}
} else {
authorUsername = author.Name
}
committerUsername := ""
committer, ok := pc.emailUsers[commit.CommitterEmail]
if !ok {
committer, err = user_model.GetUserByEmail(ctx, commit.CommitterEmail)
if err == nil {
// TODO: check errors other than email not found.
committerUsername = committer.Name
pc.emailUsers[commit.CommitterEmail] = committer
}
} else {
committerUsername = committer.Name
}
fileStatus, err := git.GetCommitFileStatus(ctx, repoPath, commit.Sha1)
if err != nil {
return nil, fmt.Errorf("FileStatus [commit_sha1: %s]: %w", commit.Sha1, err)
}
return &api.PayloadCommit{
ID: commit.Sha1,
Message: commit.Message,
URL: fmt.Sprintf("%s/commit/%s", repoLink, url.PathEscape(commit.Sha1)),
Author: &api.PayloadUser{
Name: commit.AuthorName,
Email: commit.AuthorEmail,
UserName: authorUsername,
},
Committer: &api.PayloadUser{
Name: commit.CommitterName,
Email: commit.CommitterEmail,
UserName: committerUsername,
},
Added: fileStatus.Added,
Removed: fileStatus.Removed,
Modified: fileStatus.Modified,
Timestamp: commit.Timestamp,
}, nil
}
// ToAPIPayloadCommits converts a PushCommits object to api.PayloadCommit format.
// It returns all converted commits and, if provided, the head commit or an error otherwise.
func (pc *PushCommits) ToAPIPayloadCommits(ctx context.Context, repoPath, repoLink string) ([]*api.PayloadCommit, *api.PayloadCommit, error) {
commits := make([]*api.PayloadCommit, len(pc.Commits))
var headCommit *api.PayloadCommit
if pc.emailUsers == nil {
pc.emailUsers = make(map[string]*user_model.User)
}
for i, commit := range pc.Commits {
apiCommit, err := pc.toAPIPayloadCommit(ctx, repoPath, repoLink, commit)
if err != nil {
return nil, nil, err
}
commits[i] = apiCommit
if pc.HeadCommit != nil && pc.HeadCommit.Sha1 == commits[i].ID {
headCommit = apiCommit
}
}
if pc.HeadCommit != nil && headCommit == nil {
var err error
headCommit, err = pc.toAPIPayloadCommit(ctx, repoPath, repoLink, pc.HeadCommit)
if err != nil {
return nil, nil, err
}
}
return commits, headCommit, nil
}
// AvatarLink tries to match user in database with e-mail
// in order to show custom avatar, and falls back to general avatar link.
func (pc *PushCommits) AvatarLink(ctx context.Context, email string) string {
if pc.avatars == nil {
pc.avatars = make(map[string]string)
}
avatar, ok := pc.avatars[email]
if ok {
return avatar
}
size := avatars.DefaultAvatarPixelSize * setting.Avatar.RenderedSizeFactor
u, ok := pc.emailUsers[email]
if !ok {
var err error
u, err = user_model.GetUserByEmail(ctx, email)
if err != nil {
pc.avatars[email] = avatars.GenerateEmailAvatarFastLink(ctx, email, size)
if !user_model.IsErrUserNotExist(err) {
log.Error("GetUserByEmail: %v", err)
return ""
}
} else {
pc.emailUsers[email] = u
}
}
if u != nil {
pc.avatars[email] = u.AvatarLinkWithSize(ctx, size)
}
return pc.avatars[email]
}
// CommitToPushCommit transforms a git.Commit to PushCommit type.
func CommitToPushCommit(commit *git.Commit) *PushCommit {
return &PushCommit{
Sha1: commit.ID.String(),
Message: commit.Message(),
AuthorEmail: commit.Author.Email,
AuthorName: commit.Author.Name,
CommitterEmail: commit.Committer.Email,
CommitterName: commit.Committer.Name,
Timestamp: commit.Author.When,
}
}
// GitToPushCommits transforms a list of git.Commits to PushCommits type.
func GitToPushCommits(gitCommits []*git.Commit) *PushCommits {
commits := make([]*PushCommit, 0, len(gitCommits))
for _, commit := range gitCommits {
commits = append(commits, CommitToPushCommit(commit))
}
return &PushCommits{
Commits: commits,
HeadCommit: nil,
CompareURL: "",
Len: len(commits),
avatars: make(map[string]string),
emailUsers: make(map[string]*user_model.User),
}
}