Kaffe v1.14.1 Kaffe.GroupMember View Source
Note: The brod_group_member
behavior is used.
Consume messages from a Kafka topic for a consumer group. There is one brod group member per topic! So as new topics are added to configuration so are the number of brod group members. Likewise, if you're using something like Heroku Kafka and have multiple dynos for your consumer, there will be a Kaffe.GroupMember per dyno and each group member will receive a equal set of partition assignments for each topic.
The actual consumption is delegated to a series of subscribers, see
Kaffe.Subscriber
for details on how messages are processed.
The subscribers are assigned generations. Each generation represents a specific configuration. In order to allow the partitions to be rebalanced on startup, there is a delay between receiving a set of assignments associated with that generation and actually creating the subscribers. If a new generation is received in the mean time, the older generation is discarded.
See the follow for more details: https://github.com/klarna/brod/blob/master/src/brod_group_member.erl https://github.com/klarna/brucke/blob/master/src/brucke_member.erl
Link to this section Summary
Functions
Callback implementation for c::brod_group_member.assign_partitions/3
.
Callback implementation for c::brod_group_member.assignments_received/4
.
Callback implementation for c::brod_group_member.assignments_revoked/1
.
Returns a specification to start this module under a supervisor.
Callback implementation for c::brod_group_member.get_committed_offsets/2
.
Invoked when the server is started. start_link/3
or start/3
will
block until it returns.
Link to this section Functions
assign_partitions(pid, members, topic_partitions) View Source
Callback implementation for c::brod_group_member.assign_partitions/3
.
assignments_received(pid, member_id, generation_id, assignments) View Source
Callback implementation for c::brod_group_member.assignments_received/4
.
assignments_revoked(pid) View Source
Callback implementation for c::brod_group_member.assignments_revoked/1
.
child_spec(arg) View Source
Returns a specification to start this module under a supervisor.
See Supervisor
.
get_committed_offsets(group_member_pid, topic_partitions) View Source
Callback implementation for c::brod_group_member.get_committed_offsets/2
.
init(list) View Source
Invoked when the server is started. start_link/3
or start/3
will
block until it returns.
args
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 callingSupervisor.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
.