Changelog

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Below is a non-exhaustive list of changes between gen_rpc versions.

Unreleased

3.0.1

  • Acceptor processes are not registered under a name by default, since each connection created a new atom that is never garbage collected. Set named_acceptors to true to name them after the connected peer
  • Fix the acceptor and the client crashing with a function_clause error when they receive an exit signal from another process. They now stop with the reason of the signal

3.0.0

  • Deprecate support for Erlang < 25.0 and support up to Erlang/OTP 29
  • Support monitoring nodes with gen_rpc:monitor_node/2
  • Support EC SSL certificates, the RSA test certificates (priv/ssl) were removed
  • Support cookie per node configuration
  • Support external cookie validation mechanism
  • Support custom TCP socket options for the whole server and client with the tcp_server_options and tcp_client_options settings, merged with the defaults
  • Support keepalive that actively keeps a client connection alive, configured by keepalive_interval
  • SSL now enforces TLS 1.3 only, with AEAD cipher suites, an EC-only key exchange and ECDSA-only signature algorithms (RSA certificates are rejected). The key exchange prefers hybrid post-quantum (ML-KEM) groups where available. TLS 1.2 and older and the legacy cipher suites are not supported anymore
  • Continuous integration moved from Travis CI to GitHub Actions and the Docker integration tests use Docker Compose (make integration)
  • The authenticate_server/1 driver callback has been replaced by authenticate_to_server/2 and drivers need to implement getstat/2, recv/2, close/1 and verify_peer/2. The authentication handshake itself is shared by the drivers, see gen_rpc_driver:authenticate_to_server/3 and gen_rpc_driver:authenticate_client/4
  • Clients connect and authenticate before their process is started, so a node that is slow to answer does not block the clients of other nodes. Concurrent requests for the same client share one connection attempt
  • Casts, abcast, sbcast and eval_everywhere to a running client no longer spawn a process
  • The send timeout of a client socket is only set when it changes
  • Debug logging no longer builds its arguments when debug logging is disabled
  • Tests use the peer module instead of the deprecated slave module

2.1.0

  • Support multiple connections per node using aribtrary keys.

  • Add support for Linux and Darwin/macOS custom keepalive settings to detect socket issues faster.

2.0.1

  • Support external node driver/port discovery.

2.0.0

This release boasts a major rengineer/refactor of gen_rpc that includes quite a few new features:

  • The server and acceptor FSMs have been converted to gen_statem to follow Erlang's best practices and development. As a result, support for Erlang releases older than 19.1 has been dropped.

  • Specific options, leveraging Erlang 19, have been enabled such as off-heap mailboxes for client and acceptor, and higher priorities for all gen_rpc processes.

  • Ports are not dynamically assigned anymore as it shows that, after some research, offers no additional benefits to having a static port listener. That means less processes to supervise and less moving parts where something can go wrong.

  • Support for SSL has been added. Please refer to the README for more information on how to use it.

  • Module version control support has been added, effectively allowing you to only make RPC calls to nodes that run specific versions of modules.

  • lager support has been dropped in favor of the logging backend-agnostic library hut, in order to better support Elixir installations. The test suite and development profiles still use lager but this doesn't interfere with production deployments of gen_rpc.

  • Tests have been updated to test more edge cases, including new SSL functionality.

  • Some options in gen_rpc.app.src have changed names to better describe what they do. Again, pleaserefer to the README to verify your preexisting settings are consistent with their new names.

  • Various smaller bugs have been fixed and various responses have been massaged for consistency.

1.0.2

  • Implemented blacklisting/whitelisting of modules available for RPC.

  • Implemented abcast and sbcast support.

1.0.1

  • Updated documentation

  • Updated/optimized various TCP options

  • Updated tests to include more edge cases

  • Support client-configurable listener port per remote node

  • Small code refactoring and cleanup

1.0.0

This release drops the hybrid RPC/TCP approach and uses a separate TCP listener to emulate initial RPC communication. In addition, this release includes:

  • Updated documentation

  • Added integration tests using Docker