package attributes
import (
"context"
"log"
"net/http"
"sync"
"time"
"last9-mcp/internal/models"
"last9-mcp/internal/telemetry/logs"
"last9-mcp/internal/telemetry/traces"
)
const defaultTTL = 2 * time.Hour
// AttributeCache caches log and trace attribute names fetched from the API.
type AttributeCache struct {
client *http.Client
cfg models.Config
logAttrs []string
traceAttrs []string
lastFetched time.Time
ttl time.Duration
mu sync.RWMutex
}
// NewAttributeCache creates a new AttributeCache.
func NewAttributeCache(client *http.Client, cfg models.Config) *AttributeCache {
return &AttributeCache{
client: client,
cfg: cfg,
ttl: defaultTTL,
}
}
// Warm performs an initial best-effort fetch of both log and trace attributes.
func (c *AttributeCache) Warm(ctx context.Context) {
c.mu.Lock()
defer c.mu.Unlock()
updated := false
logAttrs, err := logs.FetchLogAttributeNames(ctx, c.client, c.cfg)
if err != nil {
log.Printf("Warning: failed to warm log attributes cache: %v", err)
} else {
c.logAttrs = logAttrs
updated = true
}
traceAttrs, err := traces.FetchTraceAttributeNames(ctx, c.client, c.cfg)
if err != nil {
log.Printf("Warning: failed to warm trace attributes cache: %v", err)
} else {
c.traceAttrs = traceAttrs
updated = true
}
if updated {
c.lastFetched = time.Now()
}
}
// GetLogAttributes returns cached log attribute names.
func (c *AttributeCache) GetLogAttributes() []string {
c.mu.RLock()
defer c.mu.RUnlock()
attrs := make([]string, len(c.logAttrs))
copy(attrs, c.logAttrs)
return attrs
}
// GetTraceAttributes returns cached trace attribute names.
func (c *AttributeCache) GetTraceAttributes() []string {
c.mu.RLock()
defer c.mu.RUnlock()
attrs := make([]string, len(c.traceAttrs))
copy(attrs, c.traceAttrs)
return attrs
}
// IsStale returns true if the cache is older than the TTL.
func (c *AttributeCache) IsStale() bool {
c.mu.RLock()
defer c.mu.RUnlock()
return time.Since(c.lastFetched) > c.ttl
}
// RefreshIfStale re-fetches attributes if the cache has expired.
// Returns nil on success, error otherwise.
func (c *AttributeCache) RefreshIfStale(ctx context.Context) error {
if !c.IsStale() {
return nil
}
c.mu.Lock()
defer c.mu.Unlock()
// Double-check after acquiring write lock
if time.Since(c.lastFetched) <= c.ttl {
return nil
}
logAttrs, err := logs.FetchLogAttributeNames(ctx, c.client, c.cfg)
if err != nil {
return err
}
traceAttrs, err := traces.FetchTraceAttributeNames(ctx, c.client, c.cfg)
if err != nil {
return err
}
c.logAttrs = logAttrs
c.traceAttrs = traceAttrs
c.lastFetched = time.Now()
return nil
}
