pg(3)

MODULE
pg - Distributed, Named Process Groups

DESCRIPTION

This (experimental) module implements process groups. A process group is a group of processes that can be accessed by a common name. For example, a group named foobar can include a set of processes as members of this group and they can be located on different nodes.

When messages are sent to the named group, all members of the group receive the message. The messages are serialized. If the process P1 sends the message M1 to the group, and process P2 simultaneously sends message M2, then all members of the group receive the two messages in the same order. If members of a group terminate, they are automatically removed from the group.

This module is not complete. The module is inspired by the ISIS system and the causal order protocol of the ISIS system should also be implemented. At the moment, all messages are serialized by sending them through a group master process.

EXPORTS

create(PgName) -> ok | {error, Reason}

    Types
        PgName = term()
        Reason = already_created | term()

    Creates an empty group named PgName on the current node.

create(PgName, Node) -> ok | {error, Reason}

    Types
        PgName = term()
        Node = node()
        Reason = already_created | term()

    Creates an empty group named PgName on the node Node.

join(PgName, Pid) -> Members

    Types
        PgName = term()
        Pid = pid()
        Members = [pid()]

    Joins the pid Pid to the process group PgName. Returns a list of all old members of the group.

send(PgName, Msg) -> void()

    Types
        PgName = Msg = term()

    Sends the tuple {pg_message, From, PgName, Msg} to all members of the process group PgName.

    Failure: {badarg, {PgName, Msg}} if PgName is not a process group (a globally registered name).

esend(PgName, Msg) -> void()

    Types
        PgName = Msg = term()

    Sends the tuple {pg_message, From, PgName, Msg} to all members of the process group PgName, except ourselves.

    Failure: {badarg, {PgName, Msg}} if PgName is not a process group (a globally registered name).

members(PgName) -> Members

    Types
        PgName = term()
        Members = [pid()]

    Returns a list of all members of the process group PgName.