53 lines
1.6 KiB
Go
53 lines
1.6 KiB
Go
// Package cache wraps rueidis with the semantic-key convention used by the
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// analytics service. Keys follow cache:<kind>:<workspace_id>:<hash(params)>
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// so a workspace can be invalidated without scanning unrelated entries.
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package cache
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import (
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"context"
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"crypto/sha256"
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"encoding/hex"
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"encoding/json"
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"errors"
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"fmt"
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"time"
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"github.com/redis/rueidis"
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)
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type Cache struct {
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client rueidis.Client
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}
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func New(client rueidis.Client) *Cache { return &Cache{client: client} }
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// Key builds a deterministic cache key for the given (kind, workspace, params).
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// Params must JSON-serialize stably -- use a struct or a sorted map.
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func Key(kind, workspaceID string, params any) (string, error) {
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raw, err := json.Marshal(params)
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if err != nil {
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return "", fmt.Errorf("cache key marshal: %w", err)
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}
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sum := sha256.Sum256(raw)
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return fmt.Sprintf("cache:%s:%s:%s", kind, workspaceID, hex.EncodeToString(sum[:16])), nil
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}
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// Get returns (value, true) on hit and (nil, false) on miss. Any redis error
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// is treated as a miss -- the caller falls through to the underlying source.
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func (c *Cache) Get(ctx context.Context, key string) ([]byte, bool) {
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res := c.client.Do(ctx, c.client.B().Get().Key(key).Build())
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b, err := res.AsBytes()
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if err != nil {
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if errors.Is(err, rueidis.Nil) {
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return nil, false
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}
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return nil, false
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}
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return b, true
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}
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// Set writes the value with a TTL.
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func (c *Cache) Set(ctx context.Context, key string, value []byte, ttl time.Duration) error {
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return c.client.Do(ctx, c.client.B().Set().Key(key).Value(rueidis.BinaryString(value)).Ex(ttl).Build()).Error()
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}
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