# Secrets, modules and alerts

Three screens that have nothing to do with each other except that an
instance you actually depend on needs all of them.

## Secrets

A node never holds a credential. A parameter written as

```json
{"$secret": "influx-token"}
```

is replaced with the stored value when the node is built, and the editor
renders any field a node type marks as a credential as a picker over what you
have stored.

**Secrets** is where the values live. Add a name and a value; the value is
never shown again, and the list only ever shows names.

They are encrypted at rest with a key derived from the instance's
`SECRET_KEY`, and kept **outside** the flow repository. That matters because
flows are a git repository you may well push somewhere: what gets committed and
shared never contains a password.

A name that no longer resolves is a clear error on the node that wanted it
("No secret named 'x'; add it under Secrets") rather than a mysterious
authentication failure.

!!! warning "Rotating `SECRET_KEY`"

    The secrets store is encrypted with a key derived from it. Change
    `SECRET_KEY` and the store no longer decrypts. Re-enter the secrets, or
    plan the rotation properly.

## Modules

Node code runs in a virtual environment of its own, on the instance's data
volume, separate from the packages Fluksio itself runs on. A pin of yours can
never shadow one of ours, and vice versa.

**Modules** is a pip manifest and an **Apply** button. It is installed with
`uv pip sync`, so a line you delete is uninstalled rather than left behind.
The manifest is versioned alongside your flows, so what a deployment installed
is recorded with what uses it.

The page shows what is currently installed, the interpreter's Python version,
and whether the manifest and the environment agree. A failed resolve comes back
as `uv`'s own output, in the pane, because that is the only thing anyone can
act on.

An install takes effect immediately: the worker processes pick up the new
interpreter state without the engine restarting.

!!! note "Big scientific stacks"

    Installing torch into this venv works and is often the simplest thing. The
    alternative, when you already have an environment you would rather not
    duplicate, is to attach it as a worker: `fluksio-worker --python
    /path/to/venv/bin/python`. See [Remote workers](../code/workers.md).

## Alerts

Everything that goes wrong already travels the engine's event bus. Alerts is
where you say who hears about it.

### Channels

| Kind | Settings |
|---|---|
| **ntfy** | server, topic, and a token for a protected topic |
| **SMTP** | an address to send to (the instance's mail settings do the rest) |
| **Webhook** | a URL to POST to |
| **Dashboard** | a message name a notification widget reads |

Any channel setting may hold a `{"$secret": "name"}` reference instead of a
literal, so a webhook URL with a token in it does not sit in the config.

### Rules

A rule is a set of events and the channels they go to. **A rule with no events
ticked covers all of them**, including ones added in later versions, which is
usually what you want for the first rule you write.

| Event | Fires when |
|---|---|
| `node_error` | a node failed |
| `node_health` | a connection dropped |
| `flow_quarantined` | a flow crashed often enough that the engine stopped restarting it |
| `task_crashed` | a background task crashed |
| `engine_degraded` | the engine is struggling |
| `cascade_dropped` | work was given up on |
| `queue_unavailable` | the work queue is unreachable |

**Test** sends one message through a channel so you find out it is misconfigured
now rather than at three in the morning.

### What it mostly does is not send

This is the part worth knowing before you decide it is broken:

- the same fault repeating is **one** alert, with a cooldown (15 minutes by
  default per rule)
- a connection flapping is one story, not one alert per transition
- however bad it gets, **ten alerts an hour** is the ceiling

An engine that is genuinely on fire produces a handful of messages, not
thirty-six thousand.

## Admin: users

Superusers get an **Admin** screen: add, edit and remove accounts, and see who
is a superuser.

Accounts that arrived through a portal are badged *Portal*. They have no
password (they sign in at the portal, not here) and they are never
superusers. Deleting one cuts their access immediately and independently of the
portal, so it works even if the portal cannot be reached. See
[Accounts and the portal](portal.md).

The same screen manages OAuth clients, which is how [agents](../code/agents.md)
are registered.

## Settings

Your own account: name, email, password, and appearance (light, dark, or
follow the system).

**Remote access** is where an instance is paired with a portal, remote
users are admitted, and the link is cut again. That has [its own
page](portal.md).