added config struct for cache so we can change timeouts in testing

internal/cache/cache.go

@@ -16,29 +16,43 @@ import (
 )
 
 type Cache struct {
-	cacheRoot     string
-	mirrorURLs    []string
-	mirroredRepos []string
+	cfg       CacheConfig
 	mirrorIdx atomic.Uint32
 	sf        singleflight.Group //prevents duplicate downloads
 	mu        sync.Mutex
 	client    http.Client
 }
 
-func NewCache(cacheRoot string, mirrorURLs []string, mirroredRepos []string) *Cache {
-	transport := &http.Transport{
-		DialContext: (&net.Dialer{
-			Timeout: 5 * time.Second,
-		}).DialContext,
-		ResponseHeaderTimeout: 10 * time.Second,
+type CacheConfig struct {
+	cacheRoot             string
+	mirrorURLs            []string
+	mirroredRepos         []string
+	DialTimeout           time.Duration
+	ResponseHeaderTimeout time.Duration
+	ClientTimeout         time.Duration
 }
 
-	return &Cache{
+func NewCache(cacheRoot string, mirrorURLs []string, mirroredRepos []string) *Cache {
+	cfg := CacheConfig{
 		cacheRoot:             cacheRoot,
 		mirrorURLs:            mirrorURLs,
 		mirroredRepos:         mirroredRepos,
+		DialTimeout:           5 * time.Second,
+		ResponseHeaderTimeout: 10 * time.Second,
+		ClientTimeout:         15 * time.Second,
+	}
+
+	transport := &http.Transport{
+		DialContext: (&net.Dialer{
+			Timeout: cfg.DialTimeout,
+		}).DialContext,
+		ResponseHeaderTimeout: cfg.ResponseHeaderTimeout,
+	}
+
+	return &Cache{
+		cfg: cfg,
 		client: http.Client{
-			Timeout:   15 * time.Second,
+			Timeout:   cfg.ClientTimeout,
 			Transport: transport,
 		},
 	}
@@ -65,8 +79,8 @@ func (c *Cache) fetch(pkgName string) error {
 	// pkgName is relative to the localRoot
 	// ie pkgName includes /{repo}/os/{arch}/ and the actual name linux-x.x.x.pkg.tar.zst
 	tempPkgName := pkgName + ".tmp"
-	tempPkgPath := filepath.Join(c.cacheRoot, tempPkgName) //full tmp write path
-	outPkg := filepath.Join(c.cacheRoot, pkgName)
+	tempPkgPath := filepath.Join(c.cfg.cacheRoot, tempPkgName) //full tmp write path
+	outPkg := filepath.Join(c.cfg.cacheRoot, pkgName)
 	pkgURL := c.nextMirror() + pkgName
 
 	log.Printf("fetching %v", pkgURL)
@@ -102,5 +116,5 @@ func (c *Cache) fetch(pkgName string) error {
 
 func (c *Cache) nextMirror() string {
 	idx := c.mirrorIdx.Add(1) - 1
-	return c.mirrorURLs[idx%uint32(len(c.mirrorURLs))]
+	return c.cfg.mirrorURLs[idx%uint32(len(c.cfg.mirrorURLs))]
 }

internal/cache/cache_test.go

@@ -22,7 +22,9 @@ func newTestServer(t *testing.T, handler http.HandlerFunc) *httptest.Server {
 func newTestCache(t *testing.T, mirrorURL []string) *Cache {
 	t.Helper()
 	mirroredRepos := []string{"core", "extra"}
-	return NewCache(t.TempDir(), mirrorURL, mirroredRepos)
+	c := NewCache(t.TempDir(), mirrorURL, mirroredRepos)
+	c.client.Timeout = 500 * time.Millisecond
+	return c
 }
 
 func TestFetchFileExists(t *testing.T) {
@@ -39,7 +41,7 @@ func TestFetchFileExists(t *testing.T) {
 		t.Fatalf("Fetch failed %v", err)
 	}
 
-	fakefilepath := filepath.Join(c.cacheRoot, "fakefile")
+	fakefilepath := filepath.Join(c.cfg.cacheRoot, "fakefile")
 
 	data, err := os.ReadFile(fakefilepath)
 	if err != nil {

internal/cache/refresh.go

@@ -8,7 +8,7 @@ func (c *Cache) Refresh() error {
 	}
 	defer c.mu.Unlock()
 
-	for _, repo := range c.mirroredRepos {
+	for _, repo := range c.cfg.mirroredRepos {
 		if err := c.refreshDB(repo); err != nil {
 			return err
 		}