DHT Prom Alias RPC

Protomux RPC for registering aliases with a DHT-Prometheus service.

Usage

See ./example.js

Install

``
npm i dht-prom-alias-rpc
`

API

$3

#### const rpcServer = new AliasRpcServer(swarm, secret, putAliasCb)

Create a new alias rpc server.

swarm is a Hyperswarm instance. Its life cycle is NOT managed by the RPC server.

Note: rpcServer.swarm.listen() needs to be called before the rpcServer has a public key and connections are accepted.

secret is a 32-byte secret. Only clients which know this secret will be allowed to register aliases.

putAliasCb is a (possibly async) function which is called every time a valid alias request is received. It should return true if the alias was updated, and false otherwise (if it already existed). To refuse to register an alias, throw an error.

#### rpcServer.publicKey

Public key the rpc server is listening on.

#### Events

All events contain a uid, which is unique per connection, and the remotePublicKey of the other peer.

#### rpcServer.on('connection-open', ({ uid, remotePublicKey, remoteAddress }))

Emitted whenever a new connection is opened.

remoteAddress is the address where the other peer is listening, for example 127.0.0.1:5444.

#### rpcServer.on('connection-error', ({ uid, error, remotePublicKey }))

Emitted whenever a connection errors. Connection errors are expected, and this is not a call to action (the connection will clean itself up), but it can be useful for logging.

#### rpcServer.on('connection-close', ({ uid, remotePublicKey }))

Emitted whenever a connection is closed.

#### rpcServer.on('alias-unauthorised', ({ uid, remotePublicKey, targetPublicKey, alias, remoteAddress }))

Emitted whenever a peer tried to register an alias without knowing the correct secret.

remoteAddress is the address (ip:port) of the peer who tried to map the alias to targetPublicKey.

#### rpcServer.on('alias-request', ({ uid, remotePublicKey, targetPublicKey, alias, hostname, service }))

Emitted whenever a peer who knows the secret tries to register an alias.

remotePublicKey is the publicKey of the peer who requests to map the alias to targetPublicKey.

hostname and service contain the values provided in the request.

#### rpcServer.on('alias-success', ({ uid, remotePublicKey, alias, targetPublicKey, updated }))

Emitted whenever an alias was successfully registered for the targetPublicKey. The boolean updated indicates whether any changes were made.

#### rpcServer.on('alias-error', ({ uid, remotePublicKey, error }))

Emitted whenever the putAliacCb threw an error. error contains the error object.

$3

#### const client = new AliasRpcClient(serverPubKey, secret, protomuxRpcClient)

Create a new alias rpc client.

serverPubKey is the public key of the alias rpc server.

secret is the secret shared with the server.

protomuxRpcClient is a Protomux RPC Client instance. Its lifecycle is NOT managed by the rpc client.

#### const updated = await client.registerAlias(alias, targetKey, hostname, service, opts?)

Register an alias, mapping it to the provided targetKey.

Hostname and service are included for easy filtering in prometheus:

hostname identifies the machine where the process runs (typically os.hostname()).

service indicates the kind of service registered.

opts include:
- timeout max request duration before it times out (in ms)

Returns a boolean updated which is true when the entry was not yet present in the server.

#### Events

#### client.on('alias-attempt', ({ uid, alias, targetKey, hostname, service }))

Emitted whenever an alias request is attempted.

uid is a unique id for the attempt to map alias to targetKey, with as additional info hostname and service.

#### client.on('connection-error', ({ error, alias, targetKey, uid }))`

Emitted whenever a connection errors. Connection errors are expected, and this is not a call to action (the connection will clean itself up), but it can be useful for logging.