Process

A process defines a supervised task.

Tipically a process listens for shutdown request and terminates following its workflow logic.

A process may decide to ignore a shutdown request: in this case the supervisor may force the termination of the task with a Visor.ProcessInterrupt exception after a user defined amount of time.

If a process returns or fails with an exception the supervisor applies a defined restart policy.

The full signatures of process methods are:

process(fn::Function;
        args::Tuple=(),
        namedargs::NamedTuple=(;),
        force_interrupt_after::Real=1.0,
        stop_waiting_after::Real=Inf,
        debounce_time::Real=NaN,
        trace_exception::Bool=false,
        thread::Bool=false,
        restart::Symbol=:transient)

process(name::String,
        fn::Function;
        args::Tuple=(),
        namedargs::NamedTuple=(;),
        force_interrupt_after::Real=1.0,
        stop_waiting_after::Real=Inf,
        debounce_time::Real=NaN,
        trace_exception::Bool=false,
        thread::Bool=false,
        restart::Symbol=:transient)

Where:

• name: a user defined process name. Used for getting process with from_path api. When name argument is missing the process name default to string(fn);
• fn: the process function;
• args: a Tuple of function arguments;
• namedargs: a NamedTuple of named function arguments;
• force_interrupt_after: the amount of time in seconds after which if a process does not terminate by itself it is forcibly interrupted.
• stop_waiting_after: the amount of time in seconds after which the supervisor stop waiting for the task if a task does not terminate because it "adsorbs" the Visor.ProcessException exception.
• debounce_time: wait time in seconds before restarting a process. Default to NaN (restart immediately);
• trace_exception: boolean flag for printing the error stacktrace when process exits by an exception.
• thread: boolean flag for threaded versus asynchronous task;
• restart: one of the symbols:
  • :permanent the function is always restarted;
  • :transient restarted in case of exit caused by an exception;
  • :temporary never restarted;