# Signals, exit codes and files

> How ansage reacts to signals, what its exit codes mean, its environment variables, files and NOTIFICATIONs.

## Signals

| Signal                                 | Effect                                                                                                                       |
| -------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------- |
| SIGHUP                                 | reload the config (like `ansage reload`, but the result is only logged)                                                      |
| SIGTERM, SIGINT                        | stop: with `drain_time`, drain first; then close every session with Cease / Administrative Shutdown and remove kernel routes |
| second SIGTERM/SIGINT during the drain | end the drain at once and stop                                                                                               |

## Exit codes

### Daemon

| Code | Meaning                                                 | systemd unit                                    |
| ---- | ------------------------------------------------------- | ----------------------------------------------- |
| 0    | stopped by a signal                                     | stays stopped                                   |
| 1    | error (invalid config, cannot bind, missing capability) | restarted after 5 s (`Restart=on-failure`)      |
| 75   | `ansage upgrade`: restart me                            | restarted at once (`RestartForceExitStatus=75`) |

### Client commands

0 on success, 1 on an error (no socket, unknown neighbor, invalid prefix, refused reload). `ansage
upgrade` exits 0 only once every neighbor is back with our full table; `ansage check` 0 if the
config is valid.

## systemd notifications

With `Type=notify-reload` (or `Type=notify`) ansage reports through `NOTIFY_SOCKET`:

| Message                                      | When                                                   |
| -------------------------------------------- | ------------------------------------------------------ |
| `READY=1`                                    | sessions started (also after a reload)                 |
| `RELOADING=1`                                | a reload begins                                        |
| `STOPPING=1`                                 | a stop begins                                          |
| `EXTEND_TIMEOUT_USEC`, `STATUS=draining ...` | with `drain_time`: the stop timeout grows by the drain |

## Environment

| Variable                            | Effect                                                                                                                       |
| ----------------------------------- | ---------------------------------------------------------------------------------------------------------------------------- |
| `RUST_LOG`                          | log filter, default `info`; e.g. `ansage=debug`                                                                              |
| `NO_COLOR`                          | no colors in text logs (colors are only used on a terminal anyway)                                                           |
| `NOTIFY_SOCKET`                     | set by systemd; enables the notifications above                                                                              |
| `ANSAGE_SUPERVISED=1`               | tells `ansage upgrade` that a supervisor restarts ansage on exit 75, see [Run without systemd](/docs/guides/without-systemd.md) |
| `ANSAGE_VERSION`, `ANSAGE_BASE_URL` | installer only, see [Install](/docs/getting-started/install.md#installer-options)                                               |

## Files

| Path                                 | What                              | Owner, mode         |
| ------------------------------------ | --------------------------------- | ------------------- |
| `/usr/local/bin/ansage`              | the binary                        | root, 0755          |
| `/etc/ansage/ansage.toml`            | the config                        | root:ansage, 0640   |
| `/etc/ansage/*`                      | e.g. `password_file` keys         | root:ansage, 0640   |
| `/etc/ansage/*.bak.TIME`             | files the installer replaced      |                     |
| `/etc/systemd/system/ansage.service` | the unit                          | root, 0644          |
| `/run/ansage/ansage.sock`            | control socket (`control_socket`) | ansage:ansage, 0660 |

`ansage` without `--config` reads `./ansage.toml`; the client commands use `--socket`, else the
`control_socket` of `--config`, else `/run/ansage/ansage.sock`.

## NOTIFICATIONs ansage sends

| Code                                              | When                                                                                              |
| ------------------------------------------------- | ------------------------------------------------------------------------------------------------- |
| Cease / Administrative Shutdown (6/2)             | stop, `ansage peer N disable` (with the `--reason` text, RFC 9003)                                |
| Cease / Peer De-configured (6/3)                  | the neighbor was removed by a reload                                                              |
| Cease / Administrative Reset (6/4)                | `ansage peer N reset`                                                                             |
| Cease / Other Configuration Change (6/6)          | the neighbor's settings changed in a reload                                                       |
| Cease / Maximum Number of Prefixes Reached (6/1)  | the neighbor exceeded `max_prefixes_ipv4/ipv6`                                                    |
| Cease / Hard Reset (6/9)                          | wraps the above when the N bit (RFC 8538) is negotiated, so the neighbor drops our routes at once |
| Cease 6/2 "ansage restarting", without Hard Reset | `ansage upgrade`: the neighbor keeps our routes as stale                                          |
| Hold Timer Expired, OPEN and UPDATE errors        | protocol errors (RFC 4271, RFC 7606)                                                              |