forgejo/models/repo
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
..
archiver.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
attachment.go Preview images for Issue cards in Project Board view (#22112) 2023-02-11 16:12:41 +08:00
attachment_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
avatar.go Add context cache as a request level cache (#22294) 2023-02-15 21:37:34 +08:00
collaboration.go Always reuse transaction (#22362) 2023-01-08 09:34:58 +08:00
collaboration_test.go Rename almost all Ctx functions (#22071) 2022-12-10 10:46:31 +08:00
fork.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
fork_test.go refactor some functions to support ctx as first parameter (#21878) 2022-12-03 10:48:26 +08:00
git.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
issue.go Rename almost all Ctx functions (#22071) 2022-12-10 10:46:31 +08:00
language_stats.go Round language stats percentage using largest remainder (#22026) 2022-12-08 10:47:47 +08:00
main_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
mirror.go Use ErrInvalidArgument in packages (#22268) 2022-12-31 12:49:37 +01:00
pushmirror.go Use ErrInvalidArgument in packages (#22268) 2022-12-31 12:49:37 +01:00
pushmirror_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
redirect.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
redirect_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
release.go 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
repo.go Fix improper HTMLURL usages in Go code (#22839) 2023-02-11 14:34:11 +08:00
repo_indexer.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
repo_list.go Remove ONLY_SHOW_RELEVANT_REPOS setting (#21962) 2023-02-04 21:26:38 +08:00
repo_list_test.go Add a simple test for external renderer (#20033) 2022-12-12 20:45:21 +08:00
repo_test.go refactor some functions to support ctx as first parameter (#21878) 2022-12-03 10:48:26 +08:00
repo_unit.go Pull Requests: setting to allow edits by maintainers by default, tweak UI (#22862) 2023-02-13 14:09:52 +08:00
star.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
star_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
topic.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
topic_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
update.go Fix error when calculate the repository size (#22392) 2023-01-13 18:54:02 +00:00
upload.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
user_repo.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
user_repo_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
watch.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
watch_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
wiki.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00
wiki_test.go Implement FSFE REUSE for golang files (#21840) 2022-11-27 18:20:29 +00:00