Migrating from Ranch 1.5 to 1.6

Ranch 1.6 added the ability to suspend and resume listeners. It also deprecates a number of features and add interfaces that will be used in Ranch 2.0.

Ranch 1.6 is compatible with Erlang/OTP 18.0 onward. Support for older releases has been removed.

Features added

• Listeners can now be suspended/resumed without stopping existing connection processes. This effectively closes the listening socket and stops the acceptor processes.
• Transport options can now be updated for suspended listeners.
• The Socket argument given when the protocol starts has been deprecated. In Ranch 2.0 the socket will be obtainable only by calling ranch:handshake/1,2.
• Ranch-specific transport options and socket options are now better separated. When passing Ranch-specific transport options, Ranch now expects to receive a map, in which case socket options are passed in the socket_opts value. When there are only socket options they can be passed to Ranch directly as a convenience.
• Any future transport option will only be added to the map type. This includes transport options added in this release.
• The transport option ack_timeout was renamed to handshake_timeout in the map type.
• The cacerts socket option is now silenced in error logs just like the certs and key options.
• The manual has been heavily updated and now features one manual page per function and module, complete with a per-function changelog, examples and more.

Experimental features added

• It is now possible to configure the restart intensity for ranch_sup using the OTP application environment. This feature will remain undocumented unless there is popular demand for it.
• Add the transport option logger that allows configuring which logger module will be used. The logger module must follow the interface of the new logger module in Erlang/OTP 21, or be set to error_logger to keep the old behavior.

Changed behaviors

• Transport modules must now implement Transport:handshake/2,3 which deprecates and will replace Transport:accept_ack/1 in Ranch 2.0. It returns a new socket and can therefore be used for implementing TLS upgrade mechanisms.

New functions

• The functions ranch:suspend_listener/1 and ranch:resume_listener/1 were added. In addition the function ranch:get_state/1 can be used to obtain the running state of a listener.
• A function ranch:wait_for_connections/3 was added.
• A function ranch:handshake/1,2 was added to replace the function ranch:accept_ack/1.

Bugs fixed

• The specs for the function Transport:sendfile/2,4,5 have been corrected. The type used for the filename was too restricting.