View Source FluentdForwarder (FluentdForwarder v0.1.0)

A Fluentd forwarder server.

options

Options

  • :net - If using :inet (IPv4 only - the default) or :inet6 (IPv6)

  • :ip - the ip to bind the server to. Must be either a tuple in the format {a, b, c, d} with each value in 0..255 for IPv4, or a tuple in the format {a, b, c, d, e, f, g, h} with each value in 0..65535 for IPv6, or a tuple in the format {:local, path} for a unix socket at the given path. If you set an IPv6, the :net option will be automatically set to :inet6. If both :net and :ip options are given, make sure they are compatible (i.e. give a IPv4 for :inet and IPv6 for :inet6). Also, see "Loopback vs Public IP Addresses".

  • :port - the port to run the server. Defaults to 4000 (http) and 4040 (https). Must be 0 when :ip is a {:local, path} tuple.

  • :handler - the FluentdForwarder.Handler to use.

  • :ref - the reference name to be used. Defaults to handler.TCP (tcp) and handler.TLS (tls). Note, the default reference name does not contain the port so in order to serve the same plug on multiple ports you need to set the :ref accordingly, e.g.: ref: MyHandler_TCP_24224, ref: MyHandler_TCP_24225, etc.

  • :protocol_options - A keyword list specifying protocol options. By default :timeout will be set to :infinity.

  • :transport_options - A keyword list specifying transport options, see Ranch docs. By default :num_acceptors will be set to 100 and :max_connections to 16_384.

All other options given at the top level must configure the underlying socket. For TCP connections, those options are listed under ranch_tcp. For example, you can set :ipv6_v6only to true if you want to bind only on IPv6 addresses.

For TLS connections, those options are described in ranch_ssl.

loopback-vs-public-ip-addresses

Loopback vs Public IP Addresses

Should your application bind to a loopback address, such as ::1 (IPv6) or 127.0.0.1 (IPv4), or a public one, such as ::0 (IPv6) or 0.0.0.0 (IPv4)? It depends on how (and whether) you want it to be reachable from other machines.

Loopback addresses are only reachable from the same host (localhost is usually configured to resolve to a loopback address). You may wish to use one if:

  • Your app is running in a development environment (such as your laptop) and you don't want others on the same network to access it.
  • Your app is running in production, but behind a reverse proxy. For example, you might have Nginx bound to a public address and serving TLS, but forwarding the traffic to your application running on the same host. In that case, having your app bind to the loopback address means that Nginx can reach it, but outside traffic can only reach it via Nginx.

Public addresses are reachable from other hosts. You may wish to use one if:

  • Your app is running in a container. In this case, its loopback address is reachable only from within the container; to be accessible from outside the container, it needs to bind to a public IP address.
  • Your app is running in production without a reverse proxy, using Ranch's TLS support.

instrumentation

Instrumentation

FluentdForwarder.Handler uses the :telemetry library for instrumentation. The following span events are published during each request:

  • [:fluentd, :forward, :connection, :start] - dispatched at the beginning of each connection
  • [:fluentd, :forward, :connection, :stop] - dispatched at the end of the connection
  • [:fluentd, :forward, :message, :received] - dispatched before successfully handling a message
  • [:fluentd, :forward, :event, :handled] - dispatched after successfully handling an event
  • [:fluentd, :forward, :event, :exception] - dispatched at the end of a message that exits

Link to this section Summary

Link to this section Types

@type proto_opts() :: Keyword.t()
@type ref() :: :ranch.ref()
@type trans_opts() :: :ranch.opts()