Persists all logs to a rotating file so history survives restarts — the admin log buffer (GamendWeb.AdminLogBuffer) is in-memory only and is lost on redeploy/restart.

Disabled unless a path is configured. Runs alongside the default stdout handler, so fly logs still receives everything. On a Fly deploy, point it at the mounted volume.

config :gamend_web, GamendWeb.Observability, log_file_path: "log/dev.log"

Backed by OTP's built-in :logger_std_h, which handles size-based rotation (max_no_bytes per file, max_no_files kept). Defaults to 10MB x 5 files.

Where the settings come from

Every knob is a declared GamendWeb.Observability setting, so it is read through Gamend.Settings.get/2 — which looks at Application.get_env(:gamend_web, GamendWeb.Observability) and then the compiled default. Nothing else. In particular get/2 does not read the environment: a host that wants env-driven settings has to splat Gamend.Settings.from_env/0 into its own runtime.exs, and a host that does not gets app config only, however the variables are set.

Both columns used to read differently — a flat :gamend_web, :log_file key and a bare LOG_FILE_PATH, from before these moved behind Gamend.Settings. Neither has resolved to anything since, and because an unconfigured path disables the handler silently, a host carrying the old line logged to stdout only and lost every run to terminal scrollback. The polyglot host was doing exactly that, undetected, until a client-side bug needed the server's account of a run and there was none to read.

A misconfigured path is still silent by design — this handler must never be the reason a boot fails — so when adding a knob here, prefer one whose absence is visible in GamendWeb.Observability rather than only at runtime.