feat: in memory adapter for entity caching cache #3137
There are no files selected for viewing
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,119 @@ | ||
| package cache | ||
|
|
||
| import ( | ||
| "bytes" | ||
| "context" | ||
| "errors" | ||
| "fmt" | ||
| "sync" | ||
| "time" | ||
|
|
||
| enginecache "github.com/wundergraph/graphql-go-tools/v2/pkg/entitycaching" | ||
| ) | ||
|
|
||
| // ErrMissingTTL reports items that were rejected because they carried no | ||
| // positive TTL. Every cached entry expires, so a TTL is mandatory. | ||
| var ErrMissingTTL = errors.New("cache item requires a positive TTL") | ||
|
|
||
| type inMemoryEntry struct { | ||
| value []byte | ||
| // expiresAt is always set, an entry without an expiry is never stored. | ||
| expiresAt time.Time | ||
| } | ||
|
|
||
| // InMemoryCache sweeps every expired entry on each call, so both methods take | ||
| // the mutex exclusively, hence a plain Mutex rather than an RWMutex. | ||
| // This cache should only be used for tests OR development and never production | ||
|
Contributor
There was a problem hiding this comment. This rather belongs to the Also this could become a major bottleneck. Using a normal mutex instead of an RWMutex forces syncronous reads to the cache for all concurrent requests on the router. You can't use an RWMutex because of I mean yeah it's only meant to be used in tests but if Ristretto can solve it for free and have it production ready for when the situation calls for it.
Contributor
Author
There was a problem hiding this comment. switched to ristretto |
||
| type InMemoryCache struct { | ||
| mu sync.Mutex | ||
| entries map[string]inMemoryEntry | ||
|
Contributor
There was a problem hiding this comment. Why not use
Contributor
Author
There was a problem hiding this comment. switched to ristretto |
||
| now func() time.Time | ||
|
Contributor
There was a problem hiding this comment. This is only for test purposes right? Have you considered using |
||
| } | ||
|
|
||
| // NewInMemoryCache returns an empty InMemoryCache ready for use. | ||
| func NewInMemoryCache() *InMemoryCache { | ||
| return &InMemoryCache{ | ||
| entries: make(map[string]inMemoryEntry), | ||
| now: time.Now, | ||
| } | ||
| } | ||
|
|
||
| // GetMany returns one result per key, in the same order as keys. It also drops | ||
| // every expired entry, including those no key in this batch asked about. | ||
| func (c *InMemoryCache) GetMany(ctx context.Context, keys []string) ([]enginecache.Result, error) { | ||
| if len(keys) == 0 { | ||
| return nil, nil | ||
| } | ||
|
|
||
| if err := ctx.Err(); err != nil { | ||
| return nil, err | ||
| } | ||
|
Contributor
There was a problem hiding this comment. I'd put this on the top like in |
||
|
|
||
| c.mu.Lock() | ||
| defer c.mu.Unlock() | ||
|
|
||
| // Sweeping first means anything still present is live, so the lookup below | ||
| // needs no expiry check of its own. | ||
| c.sweepExpired(c.now()) | ||
|
|
||
| results := make([]enginecache.Result, len(keys)) | ||
| for i, key := range keys { | ||
| entry, ok := c.entries[key] | ||
| if !ok { | ||
| continue | ||
| } | ||
| results[i] = enginecache.Result{Value: bytes.Clone(entry.value), Found: true} | ||
|
Contributor
There was a problem hiding this comment. You're not really making use of |
||
| } | ||
|
|
||
| return results, nil | ||
| } | ||
|
|
||
| // SetMany stores every item, all of which must carry a positive TTL. A single | ||
| // item without one fails the whole batch with an ErrMissingTTL and nothing is | ||
| // stored. It otherwise only fails on a cancelled context. It also drops every | ||
| // expired entry, including those no lookup has claimed. | ||
| func (c *InMemoryCache) SetMany(ctx context.Context, items []enginecache.Item) error { | ||
| if err := ctx.Err(); err != nil { | ||
| return err | ||
| } | ||
|
|
||
| if len(items) == 0 { | ||
| return nil | ||
| } | ||
|
|
||
| // Validated up front, before the lock is taken, so a batch carrying a bad | ||
| // item writes nothing at all rather than being applied in part. | ||
| for _, item := range items { | ||
| if item.TTL <= 0 { | ||
| return fmt.Errorf("%w: key %q", ErrMissingTTL, item.Key) | ||
| } | ||
| } | ||
|
|
||
| c.mu.Lock() | ||
| defer c.mu.Unlock() | ||
|
|
||
| now := c.now() | ||
| for _, item := range items { | ||
| c.entries[item.Key] = inMemoryEntry{ | ||
| value: bytes.Clone(item.Value), | ||
| expiresAt: now.Add(item.TTL), | ||
| } | ||
| } | ||
|
|
||
| // Everything just stored has a deadline in the future, so a batch never | ||
| // sweeps away its own entries. | ||
| c.sweepExpired(now) | ||
|
|
||
| return nil | ||
| } | ||
|
|
||
| // sweepExpired drops every entry that has expired by now. The caller must hold | ||
| // the mutex. A TTL of d covers [set, set+d), so an entry reaching its deadline | ||
| // exactly is already expired. | ||
| func (c *InMemoryCache) sweepExpired(now time.Time) { | ||
| for key, entry := range c.entries { | ||
| if !now.Before(entry.expiresAt) { | ||
| delete(c.entries, key) | ||
| } | ||
| } | ||
| } | ||
Oops, something went wrong.
Oops, something went wrong.
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
This error isn't specific to the in memory cache, right? I would define it in the corresponding graphql-go-tools package then and mention in the methods godoc when its returned
There was a problem hiding this comment.
Choose a reason for hiding this comment
The reason will be displayed to describe this comment to others. Learn more.
moved to graphqlgotools