fix: harden DynDNS recovery and publish v1.5.1

internal/pihole/client.go

@@ -28,6 +28,8 @@ type APIError struct {
 	Message string
 }
 
+func (e *APIError) HTTPStatusCode() int { return e.Status }
+
 func (e *APIError) Error() string {
 	message := strings.TrimSpace(e.Message)
 	if message == "" {
@@ -98,7 +100,7 @@ func (c *Client) BaseURL() string { return c.baseURL }
 
 func (c *Client) ListHosts(ctx context.Context, password string) ([]string, error) {
 	var hosts []string
-	err := c.withSession(ctx, password, func(sid string) error {
+	err := c.withSession(ctx, password, func(ctx context.Context, sid string) error {
 		var response struct {
 			Config struct {
 				DNS struct {
@@ -116,13 +118,13 @@ func (c *Client) ListHosts(ctx context.Context, password string) ([]string, erro
 }
 
 func (c *Client) AddHost(ctx context.Context, password, value string) error {
-	return c.withSession(ctx, password, func(sid string) error {
+	return c.withSession(ctx, password, func(ctx context.Context, sid string) error {
 		return c.addHost(ctx, sid, value)
 	})
 }
 
 func (c *Client) DeleteHost(ctx context.Context, password, value string) error {
-	return c.withSession(ctx, password, func(sid string) error {
+	return c.withSession(ctx, password, func(ctx context.Context, sid string) error {
 		return c.deleteHost(ctx, sid, value)
 	})
 }
@@ -131,7 +133,7 @@ func (c *Client) DeleteHost(ctx context.Context, password, value string) error {
 // Pi-hole session. Missing values are accepted so an interrupted deletion can
 // safely be retried.
 func (c *Client) DeleteHosts(ctx context.Context, password string, values []string) error {
-	return c.withSession(ctx, password, func(sid string) error {
+	return c.withSession(ctx, password, func(ctx context.Context, sid string) error {
 		for _, value := range values {
 			if err := c.doJSON(ctx, http.MethodDelete, "/config/dns/hosts/"+url.PathEscape(value), sid, nil, nil, http.StatusNoContent, http.StatusNotFound); err != nil {
 				return fmt.Errorf("Pi-hole-Eintrag %q konnte nicht gelöscht werden: %w", value, err)
@@ -145,7 +147,7 @@ func (c *Client) ReplaceHost(ctx context.Context, password, previous, replacemen
 	if previous == replacement {
 		return nil
 	}
-	return c.withSession(ctx, password, func(sid string) error {
+	return c.withSession(ctx, password, func(ctx context.Context, sid string) error {
 		if err := c.deleteHost(ctx, sid, previous); err != nil {
 			return err
 		}
@@ -167,7 +169,12 @@ func (c *Client) deleteHost(ctx context.Context, sid, value string) error {
 	return c.doJSON(ctx, http.MethodDelete, "/config/dns/hosts/"+url.PathEscape(value), sid, nil, nil, http.StatusNoContent)
 }
 
-func (c *Client) withSession(ctx context.Context, password string, operation func(string) error) error {
+func (c *Client) withSession(ctx context.Context, password string, operation func(context.Context, string) error) error {
+	// Authentication and the operation must finish before the web server's
+	// write deadline, including when a Pi-hole disappears between requests.
+	ctx, cancel := context.WithTimeout(ctx, 20*time.Second)
+	defer cancel()
+	defer c.http.CloseIdleConnections()
 	sid, err := c.authenticate(ctx, password)
 	if err != nil {
 		return err
@@ -177,7 +184,7 @@ func (c *Client) withSession(ctx context.Context, password string, operation fun
 		defer cancel()
 		_ = c.doJSON(logoutCtx, http.MethodDelete, "/auth", sid, nil, nil, http.StatusNoContent, http.StatusNotFound)
 	}()
-	return operation(sid)
+	return operation(ctx, sid)
 }
 
 func (c *Client) authenticate(ctx context.Context, password string) (string, error) {