# ssb-conn

**Repository Path**: mirrors_regular/ssb-conn

## Basic Information

- **Project Name**: ssb-conn
- **Description**: SSB plugin for establishing and managing peer connections
- **Primary Language**: Unknown
- **License**: MIT
- **Default Branch**: master
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2020-09-25
- **Last Updated**: 2026-05-17

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

<div style="text-align:center" align="center">

# SSB CONN

### SSB plugin for establishing and managing peer connections.

</div>

Also known as *"The Gossip Refactor"*, the *CONN* (Connections Over Numerous Networks) plugin replaces the old `gossip` plugin, covering all its use cases. CONN has these responsibilities:

- Persistence of pub (and other servers) addresses (in the file `~/.ssb/conn.json`)
- Monitoring of all current connections and their state (connecting, disconnecting, etc)
- Monitoring of discovered peers and suggested connections (e.g. on LAN or Bluetooth)
- Selection and scheduling of connections and disconnections
- API compatibility with the old gossip plugin


## Installation

**Prerequisites:**

- Requires **Node.js 6.5** or higher
- Requires `secret-stack@^6.2.0`

```
npm install --save ssb-conn
```

Add this plugin to ssb-server like this:

```diff
 var createSsbServer = require('ssb-server')
     .use(require('ssb-onion'))
     .use(require('ssb-unix-socket'))
     .use(require('ssb-no-auth'))
     .use(require('ssb-plugins'))
     .use(require('ssb-master'))
+    .use(require('ssb-conn'))
     .use(require('ssb-replicate'))
     .use(require('ssb-friends'))
     // ...
```

Now you should be able to access the muxrpc APIs under `ssb.conn` and `ssb.gossip`, see next section.

## API

Under `ssb.conn.*` you can call any of these APIs in your local peer.

| API | Type | Description |
|-----|------|-------------|
| **`remember(addr, data?)`** | `sync` | Stores (in cold storage) connection information about a new peer, known by its multiserver address `addr` and additional optional `data` (as an object). |
| **`forget(addr)`** | `sync` | Removes (from cold storage) connection information about a peer known by its multiserver address `addr`. |
| **`dbPeers()`** | `sync` | Returns an Iterable of ConnDB entries known at the moment. Does not reactively update once the database is written to. |
| **`connect(addr, data?)`** | `async` | Connects to a peer known by its multiserver address `addr`, and stores additional optional `data` (as an object) during its connection lifespan. |
| **`disconnect(addr)`** | `async` | Disconnects a peer known by its multiserver address `addr`. |
| **`peers()`** | `source` | A pull-stream that emits an array of all ConnHub entries whenever any connection updates (i.e. changes it state: connecting, disconnecting, connected, etc). |
| **`stage(addr, data?)`** | `sync` | Registers a suggested connection to a new peer, known by its multiserver address `addr` and additional optional `data` (as an object). |
| **`unstage(addr)`** | `sync` | Unregisters a suggested connection the peer known by its multiserver address `addr`. |
| **`stagedPeers()`** | `source` | A pull-stream that emits an array of all ConnStaging entries whenever any staging status updates (upon stage() or unstage()). |
| **`start()`** | `sync` | Triggers the start of the connection scheduler in CONN. |
| **`stop()`** | `sync` | Stops the CONN scheduler if it is currently active. |
| **`ping()`** | `duplex` | A duplex pull-stream for periodically pinging with peers, fully compatible with `ssb.gossip.ping`. |
| **`db()`** | `sync` | Returns the instance of [ConnDB](https://github.com/staltz/ssb-conn-db) currently in use. |
| **`hub()`** | `sync` | Returns the instance of [ConnHub](https://github.com/staltz/ssb-conn-hub) currently in use. |
| **`staging()`** | `sync` | Returns the instance of [ConnStaging](https://github.com/staltz/ssb-conn-staging) currently in use. |
| **`query()`** | `sync` | Returns the instance of [ConnQuery](https://github.com/staltz/ssb-conn-query) currently in use. |

An "entry" is a (tuple) array of form:

```javascript
[addr, data]
```
 where:
 - `addr` is a multiserver address (a **string** that [follows some rules](https://github.com/dominictarr/multiserver-address))
 - `data` is an **object** with additional information about the peer (fields marked 🔷 are important and often used, fields marked 🔹 come from CONN, fields marked 🔸 are ad-hoc and added by various other modules, and fields suffixed with `?` are not always present):

🔷 `key: string`: the peer's public key / feedId

🔷 `state?: 'connecting' | 'connected' | 'disconnecting'`: (only from `peers()`) the peer's current connection status

🔷 `type?: string`: what type of peer this is; it can be any string, but often is either `'lan'`, `'bt'`, `'pub'`, `'room'`, `'room-endpoint'`, `'dht'`

🔹 `inferredType?: 'bt' | 'lan' | 'dht' | 'internet' | 'tunnel'`: (only from `peers()`) when there is no `type` field, e.g. when a new and unknown peer initiates a client connection with us (as a server), then ConnHub makes a guess what type it is

🔹 `birth?: number`: Unix timestamp for when this peer was added to ConnDB

🔹 `stateChange?: number`: Unix timestamp for the last time the field `state` was changed; this is stored in ConnDB

🔹 `hubBirth?: number`: Unix timestamp for when this peer was added to ConnHub

🔹 `hubUpdated?: number`: Unix timestamp for when this data object was last updated in ConnHub

🔹 `stagingBirth?: number`: Unix timestamp for when this peer was added to ConnStaging

🔹 `stagingUpdated?: number`: Unix timestamp for when this data object was last updated in ConnStaging

🔹 `autoconnect?: boolean`: indicates whether this peer should be considered for connection in the scheduler

🔹 `failure?: number`: typically in ConnDB, this is the number of connection errors since the last successful connection

🔹 `duration?: object`: typically in ConnDB, this is a [statistics](https://www.npmjs.com/package/statistics) object to measure the duration of connection with this peer

🔹 `ping?: object`: typically in ConnDB, this is [statistics](https://www.npmjs.com/package/statistics) object of various ping health measurements

🔹 `pool?: 'db' | 'hub' | 'staging'`: this only appears in ConnQuery APIs, and indicates from which pool (ConnDB or ConnHub or ConnStaging) was this peer picked

🔸 `name?: string`: a nickname for this peer, when there isn't an [ssb-about](https://github.com/ssbc/ssb-about) name

🔸 `room?: string`: (only if `type = 'room-endpoint'`) the public key of the [room](https://github.com/staltz/ssb-room) server where this peer is in

🔸 `onlineCount?: number`: (only if `type = 'room'`) the number of room endpoints currently connected to this room

## Config

Some parameters in CONN can be configured by the user or by application code through the conventional [ssb-config](https://github.com/ssbc/ssb-config). The possible options are listed below:

```typescript
{
  "conn": {
    /**
     * Whether the CONN scheduler should start automatically as soon as the
     * SSB app is initialized. Default is `true`.
     */
    "autostart": boolean,

    /**
     * How far in the social graph should a peer be automatically connected to
     * whenever possible. Default value (when this is unspecified) is `1`.
     */
    "hops": number,

    /**
     * Whether the CONN scheduler should look into the SSB database looking for
     * messages of type 'pub' and add them to CONN. Default is `true`.
     */
    "populatePubs": boolean,
  }
}
```

## Gossip compatibility

The following gossip plugin APIs are available once you install CONN, but **these will emit deprecation warnings and might behave slightly different than the old gossip plugin**:

| API | Type |
|-----|------|
| **`ssb.gossip.peers()`** | `sync` |
| **`ssb.gossip.get(p)`** | `sync` |
| **`ssb.gossip.connect(p)`** | `async` |
| **`ssb.gossip.disconnect(p)`** | `async` |
| **`ssb.gossip.changes()`** | `source` |
| **`ssb.gossip.add(p, source)`** | `sync` |
| **`ssb.gossip.remove(p)`** | `sync` |
| **`ssb.gossip.ping()`** | `duplex` |
| **`ssb.gossip.reconnect()`** | `sync` |
| **`ssb.gossip.enable()`** | `sync` |
| **`ssb.gossip.disable()`** | `sync` |

If you want to use the new CONN infrastructure but preserve the same gossip behavior as before, use [`ssb-legacy-conn`](https://github.com/staltz/ssb-legacy-conn) which tries to mirror the gossip plugin, even its log messages.

## Learn more

<details>
  <summary>How CONN works (click here)</summary>
  <p>

![diagram.png](diagram.png)

Under the hood, CONN is based on three "pools" of peers:

- [ConnDB](https://github.com/staltz/ssb-conn-db): a persistent database of addresses to connect to
- [ConnHub](https://github.com/staltz/ssb-conn-hub): a façade API for currently active connections
- [ConnStaging](https://github.com/staltz/ssb-conn-staging): a pool of potential new connections

ConnDB contains metadata on stable servers and peers that have been successfully connectable. ConnHub is the central API that allows us to issue new connections and disconnections, as well as to track the currently active connections. ConnStaging is an in-memory ephemeral storage of new possible connections that the user might want to approve or disapprove.

Then, [ConnQuery](https://github.com/staltz/ssb-conn-query) has access to those three pools, and provides utilities to query, filter, and sort connections across all those pools.

**ConnScheduler** is an **opinionated** (⚠️) plugin that utilizes ConnQuery to select peers to connect to, then schedules connections to happen via ConnHub, as well as schedules disconnections if necessary. Being opinionated, CONN provides an easy way of replacing the default scheduler with your own scheduler, see instructions below.

There is also a **Gossip Compatibility** plugin, implementing all the legacy APIs, so that other SSB plugins that call these APIs will continue to function as normal.

When you install the ssb-plugin, it will actually setup three plugins:

```
[conn, connScheduler, gossip]
```

  </p>
</details>

<details>
  <summary>Opinions built into the default scheduler (click here)</summary>
  <p>

The default scheduler is roughly the same as the legacy ssb-gossip plugin, with some opinions removed and others added. The scheduler has two parts: discovery setup on startup, and periodic connections/disconnections.

**Discovery setup:**

- Read the SSB log and look for "pub" messages, and `remember` them
- Listen to a stream of Bluetooth nearby devices, and `stage` them

**Periodic connections/disconnections:**

- With (5sec) exponential backoff, try to connect to at most 5 room servers
- With (10sec) exponential backoff, try to connect to at most 2 non-room peers that we have connected successfully before
- With (30sec) exponential backoff, try to connect to at most 2 non-room peers that we have never with connected before
- With (1min) exponential backoff, try to connect to at most 3 non-room peers that have we always failed to connect with
- With (4min) exponential backoff, try to connect to at most 1 non-room peer that seem to run a legacy version of the gossip plugin

In none of the cases above shall we connect to a peer that we block. In addition to the above, the following actions happen automatically every (approximately) 1 second:

- Connect to (at most 3) staged peers we follow
- Disconnect from connected peers that have just been blocked by us
- Disconnect from peers that have been connected with us for more than 30min
- Disconnect from peers that have been pending in "connecting" status for too long
  - "Too long" means 30sec for LAN peers
  - "Too long" means 1min for Bluetooth peers
  - "Too long" means 5min for DHT invite peers
  - For other types of peers, "too long" means 10sec
- Stage non-blocked peers that are in ConnDB marked as `autoconnect=false`
- Unstage peers that have just been blocked by us
- Unstage LAN peers that haven't been updated in ConnStaging in 10 seconds
- Unstage Bluetooth peers that haven't been updated in ConnStaging in 30 seconds

**Database cleanups:**

Upon starting the scheduler:

- Remove database entries for any LAN or Bluetooth peers (these are rediscovered just-in-time)

**Other events:**

- Upon wakeup (from computer 'sleep'), fully reset the ConnHub
- Upon network (interface) changes, fully reset the ConnHub
- Upon a disconnection, try to connect to some peer (section above)

<ul></ul>

  </p>
</details>

<details>
  <summary>How to build your own ConnScheduler (click here)</summary>
  <p>

To experiment with your own opinions for establishing connections, you can make your own ConnScheduler, which is just a typical SSB plugin. You can write in the traditional style (like other SSB plugins), or with OOP decorators. The example below uses OOP decorators.

Here is the basic shape of the scheduler:

```javascript
import {plugin, muxrpc} from 'secret-stack-decorators';

@plugin('1.0.0')
module.exports = class ConnScheduler {
  constructor(ssb, config) {
    // basic setup here
    this.ssb = ssb;
  }

  @muxrpc('sync')
  public start = () => {
    // this is called when the scheduler should begin scheduling connections

    // You have access to CONN core here:
    const query = this.ssb.conn.query();
    this.ssb.conn.stage(addr);
    this.ssb.conn.disconnect(addr);
    // ...
  }

  @muxrpc('sync')
  public stop = () => {
    // this is called when the scheduler should cancel its jobs
  }
}
```

Note that the name of the plugin must be **exactly `ConnScheduler`** (or `connScheduler`) and it **must have the methods start() and stop()**, because the CONN core will try to use your scheduler under those names. The rest of the contents of the ConnScheduler class are up to you, you can use private methods, etc.

When you're done building your scheduler, you can export it together with CONN core and the gossip compatibility plugin like this:

```js
var CONN = require('ssb-conn/core')
var Gossip = require('ssb-conn/compat')
var ConnScheduler = require('./my-scheduler')

module.exports = [CONN, ConnScheduler, Gossip]
```

That array is a valid secret-stack plugin which you can `.use()` in ssb-server.

<ul></ul>

  </p>
</details>

<details>
  <summary>Why was the gossip plugin refactored? (click here)</summary>
  <p>

The legacy gossip plugin is one of the oldest parts of the SSB stack in Node.js, and it contained several old opinions. It wasn't designed with multiserver in mind, so it made a lot of assumptions that peers have `host`/`port` fields. Nowadays with Bluetooth and other unusual modes of connectivity, that assumption breaks down often.

The gossip plugin also did not have the concept of "staging", which is useful for ephemeral connections (LAN or Bluetooth) in spaces that may have many strangers. So the gossip plugin tended to connect as soon as possible to any peer discovered.

Also, since the gossip plugin was a monolith, it had all these concerns (cold persistence, in-memory tracking of current connections, ephemeral peers, scheduling, old and new style addresses) squashed into one file, making it hard and brittle to change the code.

The objectives with CONN were to:

- Untangle the codebase into modular components with single responsibilities
- Standardize the assumption that addresses are always multiserver addresses
- All "pools" (DB, Hub, Staging) are key-value pairs `[address, dataObject]`
- Make scheduling easily customizable but provide an opinionated default

<ul></ul>

  </p>
</details>

## License

MIT