Fall back to UTC time on time zone errors

lib/utils.ml

@@ -51,14 +51,16 @@ let redirect_out_err out proc = Sh.outputs_to ~append:() out proc
 
 let eval_sh log proc = Sh.eval @@ redirect_out_err log proc
 
+(** On systems without the local timezone set up properly (e.g., alpine linux
+    docker images), we fallback to UTC timezone. *)
+let zone () =
+  try Lazy.force Time_unix.Zone.local with Sys_error _ -> Time_unix.Zone.utc
+
 let now_coarse () =
-  let zone = Lazy.force Time_unix.Zone.local in
   let now = Time.now () in
-  Time_unix.format now "%Y-%m-%d %H:%M:%S" ~zone
+  Time_unix.format now "%Y-%m-%d %H:%M:%S" ~zone:(zone ())
 
-let now () =
-  let zone = Lazy.force Time_unix.Zone.local in
-  Time.to_filename_string ~zone @@ Time.now ()
+let now () = Time.to_filename_string ~zone:(zone ()) @@ Time.now ()
 
 let log_name ~log_base ~desc =
   let now = now () in