forgejo-federation/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.
2023-02-15 21:37:34 +08:00
..
actions Fix ref to trigger Actions (#22679) 2023-01-31 22:45:25 +00:00
activities Add context cache as a request level cache (#22294) 2023-02-15 21:37:34 +08:00
admin Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
asymkey Add context cache as a request level cache (#22294) 2023-02-15 21:37:34 +08:00
auth Support scoped access tokens (#20908) 2023-01-17 15:46:03 -06:00
avatars Add context cache as a request level cache (#22294) 2023-02-15 21:37:34 +08:00
db Move delete user to service (#22478) 2023-02-13 13:11:41 +08:00
dbfs Add some comments for recent code (#22725) 2023-02-02 11:39:38 -06:00
fixtures Do not overwrite empty DefaultBranch (#22708) 2023-02-02 14:48:48 -06:00
git Add context cache as a request level cache (#22294) 2023-02-15 21:37:34 +08:00
issues Fix more HTMLURL in templates (#22831) 2023-02-09 11:31:30 -05:00
migrations Fix migration issue. (#22867) 2023-02-11 21:28:41 +00:00
organization Add context cache as a request level cache (#22294) 2023-02-15 21:37:34 +08:00
packages Use link in UI which returned a relative url but not html_url which contains an absolute url (#21986) 2023-02-06 12:09:18 -06:00
perm Rename almost all Ctx functions (#22071) 2022-12-10 10:46:31 +08:00
project Preview images for Issue cards in Project Board view (#22112) 2023-02-11 16:12:41 +08:00
pull refactor some functions to support ctx as first parameter (#21878) 2022-12-03 10:48:26 +08:00
repo Add context cache as a request level cache (#22294) 2023-02-15 21:37:34 +08:00
secret Secrets storage with SecretKey encrypted (#22142) 2022-12-20 17:07:13 +08:00
system Add context cache as a request level cache (#22294) 2023-02-15 21:37:34 +08:00
unit Repositories: by default disable all units except code and pulls on forks (#22541) 2023-02-04 14:48:38 +08:00
unittest Implement actions (#21937) 2023-01-31 09:45:19 +08:00
user Add context cache as a request level cache (#22294) 2023-02-15 21:37:34 +08:00
webhook Support system hook API (#14537) 2023-01-28 19:12:10 +01:00
error.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
fixture_generation.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
fixture_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
main_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
migrate.go Check primary keys for all tables and drop ForeignReference (#21721) 2022-12-23 19:35:43 +08:00
migrate_test.go Check primary keys for all tables and drop ForeignReference (#21721) 2022-12-23 19:35:43 +08:00
org.go refactor some functions to support ctx as first parameter (#21878) 2022-12-03 10:48:26 +08:00
org_team.go Supports wildcard protected branch (#20825) 2023-01-16 16:00:22 +08:00
org_team_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
org_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
repo.go Implement actions (#21937) 2023-01-31 09:45:19 +08:00
repo_collaboration.go refactor some functions to support ctx as first parameter (#21878) 2022-12-03 10:48:26 +08:00
repo_collaboration_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
repo_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
repo_transfer.go Always reuse transaction (#22362) 2023-01-08 09:34:58 +08:00
repo_transfer_test.go Rename almost all Ctx functions (#22071) 2022-12-10 10:46:31 +08:00