Thread context.Context through MonthlySamplesCache

Pass context from HTTP handlers through to the cache's database query,
allowing cache reloads to be cancelled on request timeout or shutdown.

Author: pierres

internal/database/cache.go

@@ -1,6 +1,7 @@
 package database
 
 import (
+	"context"
 	"database/sql"
 	"fmt"
 	"sync"
@@ -26,8 +27,8 @@ func NewMonthlySamplesCache(db *sql.DB, query string) *MonthlySamplesCache {
 	return &MonthlySamplesCache{db: db, query: query}
 }
 
-func (c *MonthlySamplesCache) Get(startMonth, endMonth int) (map[int]int, error) {
-	all, err := c.load()
+func (c *MonthlySamplesCache) Get(ctx context.Context, startMonth, endMonth int) (map[int]int, error) {
+	all, err := c.load(ctx)
 	if err != nil {
 		return nil, err
 	}
@@ -42,7 +43,7 @@ func (c *MonthlySamplesCache) Get(startMonth, endMonth int) (map[int]int, error)
 	return result, nil
 }
 
-func (c *MonthlySamplesCache) load() (map[int]int, error) {
+func (c *MonthlySamplesCache) load(ctx context.Context) (map[int]int, error) {
 	c.mu.RLock()
 	if c.cache != nil && time.Now().Before(c.expiry) {
 		cache := c.cache
@@ -59,7 +60,7 @@ func (c *MonthlySamplesCache) load() (map[int]int, error) {
 		return c.cache, nil
 	}
 
-	rows, err := c.db.Query(c.query)
+	rows, err := c.db.QueryContext(ctx, c.query)
 	if err != nil {
 		return nil, fmt.Errorf("query monthly samples: %w", err)
 	}

internal/database/cache_test.go

@@ -1,6 +1,7 @@
 package database
 
 import (
+	"context"
 	"database/sql"
 	"testing"
 	"time"
@@ -21,7 +22,7 @@ func TestMonthlySamplesCache(t *testing.T) {
 	cache := NewMonthlySamplesCache(db, "SELECT month, count FROM test_samples")
 
 	// First load
-	res, err := cache.Get(202501, 202502)
+	res, err := cache.Get(context.Background(), 202501, 202502)
 	if err != nil {
 		t.Fatalf("Get error: %v", err)
 	}
@@ -34,7 +35,7 @@ func TestMonthlySamplesCache(t *testing.T) {
 
 	// Update DB, but cache should still be valid
 	_, _ = db.Exec(`UPDATE test_samples SET count = 300 WHERE month = 202501`)
-	res, _ = cache.Get(202501, 202502)
+	res, _ = cache.Get(context.Background(), 202501, 202502)
 	if res[202501] != 100 {
 		t.Errorf("expected cached value 100, got %d", res[202501])
 	}
@@ -44,7 +45,7 @@ func TestMonthlySamplesCache(t *testing.T) {
 	cache.expiry = time.Now().Add(-1 * time.Hour)
 	cache.mu.Unlock()
 
-	res, _ = cache.Get(202501, 202502)
+	res, _ = cache.Get(context.Background(), 202501, 202502)
 	if res[202501] != 300 {
 		t.Errorf("expected new value 300 after expiry, got %d", res[202501])
 	}

internal/packages/repository.go

@@ -258,6 +258,6 @@ func (r *SQLiteRepository) getMaxCount(ctx context.Context, startMonth, endMonth
 	return total, nil
 }
 
-func (r *SQLiteRepository) getMonthlyMaxCounts(_ context.Context, startMonth, endMonth int) (map[int]int, error) {
-	return r.monthlyMaxCache.Get(startMonth, endMonth)
+func (r *SQLiteRepository) getMonthlyMaxCounts(ctx context.Context, startMonth, endMonth int) (map[int]int, error) {
+	return r.monthlyMaxCache.Get(ctx, startMonth, endMonth)
 }

internal/popularity/repository.go

@@ -69,7 +69,7 @@ func (r *Repository[T, L]) FindByIdentifier(ctx context.Context, identifier stri
 		return nil, fmt.Errorf("query %s count: %w", r.cfg.Table, err)
 	}
 
-	samples, err := r.getSamples(startMonth, endMonth)
+	samples, err := r.getSamples(ctx, startMonth, endMonth)
 	if err != nil {
 		return nil, fmt.Errorf("get samples: %w", err)
 	}
@@ -80,7 +80,7 @@ func (r *Repository[T, L]) FindByIdentifier(ctx context.Context, identifier stri
 }
 
 func (r *Repository[T, L]) FindAll(ctx context.Context, query string, startMonth, endMonth, limit, offset int) (*L, error) {
-	samples, err := r.getSamples(startMonth, endMonth)
+	samples, err := r.getSamples(ctx, startMonth, endMonth)
 	if err != nil {
 		return nil, fmt.Errorf("get samples: %w", err)
 	}
@@ -166,7 +166,7 @@ func (r *Repository[T, L]) FindSeries(ctx context.Context, identifier string, st
 		return nil, fmt.Errorf("count series: %w", err)
 	}
 
-	samplesMap, err := r.getMonthlySamples(startMonth, endMonth)
+	samplesMap, err := r.getMonthlySamples(ctx, startMonth, endMonth)
 	if err != nil {
 		return nil, fmt.Errorf("get monthly samples: %w", err)
 	}
@@ -214,8 +214,8 @@ func (r *Repository[T, L]) queryPattern(query string) string {
 	return query + "%"
 }
 
-func (r *Repository[T, L]) getSamples(startMonth, endMonth int) (int, error) {
-	monthlySamples, err := r.getMonthlySamples(startMonth, endMonth)
+func (r *Repository[T, L]) getSamples(ctx context.Context, startMonth, endMonth int) (int, error) {
+	monthlySamples, err := r.getMonthlySamples(ctx, startMonth, endMonth)
 	if err != nil {
 		return 0, err
 	}
@@ -228,8 +228,8 @@ func (r *Repository[T, L]) getSamples(startMonth, endMonth int) (int, error) {
 	return total, nil
 }
 
-func (r *Repository[T, L]) getMonthlySamples(startMonth, endMonth int) (map[int]int, error) {
-	return r.samplesCache.Get(startMonth, endMonth)
+func (r *Repository[T, L]) getMonthlySamples(ctx context.Context, startMonth, endMonth int) (map[int]int, error) {
+	return r.samplesCache.Get(ctx, startMonth, endMonth)
 }
 
 // CalculatePopularity returns a percentage rounded to 2 decimal places, capped at 100.