elsa v0.10.0 Elsa.Wrapper

Provides a supervisable wrapper for the Elsa supervision tree to manage brod producers and consumers. Provides convenience functions for starting producer and consumer processes directly without the default supervisors brod interposes between them and the application.

By taking over supervision of the processes directly interacting with Kafka by way of a brod client, these processes can be registered independently from the client process so in the event of the client dropping its connection, the record of what processes should be producing or consuming from what topics and partitions can be immediately reconstructed instead of being dropped.

Link to this section Summary

Functions

Returns a specification to start this module under a supervisor.

Invoked when the server is started. start_link/3 or start/3 will block until it returns.

Link to this section Functions

Link to this function

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

See Supervisor.

Invoked when the server is started. start_link/3 or start/3 will block until it returns.

init_arg is the argument term (second argument) passed to start_link/3.

Returning {:ok, state} will cause start_link/3 to return {:ok, pid} and the process to enter its loop.

Returning {:ok, state, timeout} is similar to {:ok, state} except handle_info(:timeout, state) will be called after timeout milliseconds if no messages are received within the timeout.

Returning {:ok, state, :hibernate} is similar to {:ok, state} except the process is hibernated before entering the loop. See c:handle_call/3 for more information on hibernation.

Returning {:ok, state, {:continue, continue}} is similar to {:ok, state} except that immediately after entering the loop the c:handle_continue/2 callback will be invoked with the value continue as first argument.

Returning :ignore will cause start_link/3 to return :ignore and the process will exit normally without entering the loop or calling c:terminate/2. If used when part of a supervision tree the parent supervisor will not fail to start nor immediately try to restart the GenServer. The remainder of the supervision tree will be started and so the GenServer should not be required by other processes. It can be started later with Supervisor.restart_child/2 as the child specification is saved in the parent supervisor. The main use cases for this are:

  • The GenServer is disabled by configuration but might be enabled later.
  • An error occurred and it will be handled by a different mechanism than the Supervisor. Likely this approach involves calling Supervisor.restart_child/2 after a delay to attempt a restart.

Returning {:stop, reason} will cause start_link/3 to return {:error, reason} and the process to exit with reason reason without entering the loop or calling c:terminate/2.

Callback implementation for GenServer.init/1.

Link to this function

start_link(args)