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gitea/models
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.
2 years ago
..
actions Fix ref to trigger Actions (#22679) 2 years ago
activities Add context cache as a request level cache (#22294) 2 years ago
admin Implement FSFE REUSE for golang files (#21840) 2 years ago
asymkey Add context cache as a request level cache (#22294) 2 years ago
auth Support scoped access tokens (#20908) 2 years ago
avatars Add context cache as a request level cache (#22294) 2 years ago
db Move delete user to service (#22478) 2 years ago
dbfs Add some comments for recent code (#22725) 2 years ago
fixtures Do not overwrite empty DefaultBranch (#22708) 2 years ago
git Add context cache as a request level cache (#22294) 2 years ago
issues Fix more HTMLURL in templates (#22831) 2 years ago
migrations Fix migration issue. (#22867) 2 years ago
organization Add context cache as a request level cache (#22294) 2 years ago
packages Use link in UI which returned a relative url but not html_url which contains an absolute url (#21986) 2 years ago
perm Rename almost all Ctx functions (#22071) 2 years ago
project Preview images for Issue cards in Project Board view (#22112) 2 years ago
pull refactor some functions to support ctx as first parameter (#21878) 2 years ago
repo Add context cache as a request level cache (#22294) 2 years ago
secret Secrets storage with SecretKey encrypted (#22142) 2 years ago
system Add context cache as a request level cache (#22294) 2 years ago
unit Repositories: by default disable all units except code and pulls on forks (#22541) 2 years ago
unittest Implement actions (#21937) 2 years ago
user Add context cache as a request level cache (#22294) 2 years ago
webhook Support system hook API (#14537) 2 years ago
error.go Implement FSFE REUSE for golang files (#21840) 2 years ago
fixture_generation.go Implement FSFE REUSE for golang files (#21840) 2 years ago
fixture_test.go Implement FSFE REUSE for golang files (#21840) 2 years ago
main_test.go Implement FSFE REUSE for golang files (#21840) 2 years ago
migrate.go Check primary keys for all tables and drop ForeignReference (#21721) 2 years ago
migrate_test.go Check primary keys for all tables and drop ForeignReference (#21721) 2 years ago
org.go refactor some functions to support ctx as first parameter (#21878) 2 years ago
org_team.go Supports wildcard protected branch (#20825) 2 years ago
org_team_test.go Implement FSFE REUSE for golang files (#21840) 2 years ago
org_test.go Implement FSFE REUSE for golang files (#21840) 2 years ago
repo.go Implement actions (#21937) 2 years ago
repo_collaboration.go refactor some functions to support ctx as first parameter (#21878) 2 years ago
repo_collaboration_test.go Implement FSFE REUSE for golang files (#21840) 2 years ago
repo_test.go Implement FSFE REUSE for golang files (#21840) 2 years ago
repo_transfer.go Always reuse transaction (#22362) 2 years ago
repo_transfer_test.go Rename almost all Ctx functions (#22071) 2 years ago