Copyright (c) 2014, 2015 Finexkap, 2015 G-Corp, 2015, 2016 BotsUnit
Version: 2.0.0
Authors: Gregoire Lejeune ([email protected]
), Gregoire Lejeune ([email protected]
), Gregoire Lejeune ([email protected]
).
Version 2.0.0 cause changes in the following APIs :
Kafe has been tested with Kafka 0.9 and 0.10
You can also use it with Kafka 0.8 but kafe_consumer
is not compatible with this version.
brokers | [{inet:hostname(), inet:port_number()}] | List of brokers | [{"localhost", 9092}] |
pool_size | integer() | Initial connection pool/brocker | 5 |
chunk_pool_size | integer() | Size of new connection pool/brocker | 10 |
brokers_update_frequency | integer() | Frequency (ms) for brokers update | 60000 |
client_id | binary() | Client ID Name | <<"kafe">> |
api_version | integer() | API Version | 1* |
correlation_id | integer() | Correlation ID | 0 |
socket | [{sndbuf, integer()}, {recbuf, integer()}, {buffer, integer()}] | Socker configuration | [{sndbuf, 4194304}, {recbuf, 4194304}, {buffer, 4194304}] |
*
use 0
with Kafka >= 0.8 < 0.9 ; 1
with Kafka >= 0.9 < 0.10 ; 2
with Kafka >= 0.10
Example :
[
{kafe, [
{brokers, [
{"localhost", 9092},
{"localhost", 9093},
{"localhost", 9094}
]},
{pool_size, 1},
{chunk_pool_size, 2},
{brokers_update_frequency, 10000},
{client_id, <<"kafe">>},
{api_version, 1},
{correlation_id, 0},
{socket, [
{sndbuf, 4194304},
{recbuf, 4194304},
{buffer, 4194304}
]},
]}
]
Kafe use lager ; see also how to configure it.
To create a consumer, create a function with 6 parameters :
-module(my_consumer).
-export([consume/6]).
consume(CommitID, Topic, Partition, Offset, Key, Value) ->
% Do something with Topic/Partition/Offset/Key/Value
ok.
The consume
function must return ok
if the message was treated, or {error, term()}
on error.
Then start a new consumer :
...
kafe:start(),
...
kafe:start_consumer(my_group, fun my_consumer:consume/6, Options),
...
See kafe:start_consumer/3
for the available Options
.
In the consume
function, if you didn't start the consumer in autocommit mode (using before_processing | after_processing
in the commit
options),
you need to commit manually when you have finished to treat the message. To do so, use kafe_consumer:commit/4
.
When you are done with your consumer, stop it :
...
kafe:stop_consumer(my_group),
...
-module(my_consumer).
-behaviour(kafe_consumer_subscriber).
-export([init/4, handle_message/2]).
-include_lib("kafe/include/kafe_consumer.hrl").
-record(state, {
}).
init(Group, Topic, Partition, Args) ->
% Do something with Group, Topic, Partition, Args
{ok, #state{}}.
handle_message(Message, State) ->
% Do something with Message
% And update your State (if needed)
{ok, NewState}.
Then start a new consumer :
...
kafe:start().
...
kafe:start_consumer(my_group, {my_consumer, Args}, Options).
% Or
kafe:start_consumer(my_group, my_consumer, Options).
...
To commit a message (if you need to), use kafe_consumer:commit/4
.
Elixir' users can use Kafe
and Kafe.Consumer
instead of :kafe
and :kafe_consumer
.
defmodule My.Consumer do
def consume(commit_id, topic, partition, offset, key, value) do
# Do something with topic/partition/offset/key/value
:ok
end
end
defmodule My.Consumer.Subscriber do
behaviour Kafe.Consumer.Subscriber
def init(group, topic, partition, args) do
% Do something with group/topic/partition/args
% and create the state
{:ok, state}
end
def handle_message(message, state) do
% Do something with message (record Kafe.Records.message or
% function Kafe.Consumer.Subscriber.message/2)
% and update (or not)the state
{:ok, new_state}
end
end
...
Kafe.start()
...
Kafe.start_consumer(:my_group, &My.Consumer.consume/6, options)
# or
Kafe.start_consumer(:my_group, {My.Consumer.Subscriber, args}, options)
# or
Kafe.start_consumer(:my_group, My.Consumer.Subscriber, options)
...
Kafe.stop_consumer(:my_group)
...
You can enable metrics by adding a metrics module in your configuration :
{metrics, [
{metrics_mod, metrics_folsom}
]}
You can choose between Folsom ({metrics_mod, metrics_folsom}
), Exometer ({metrics_mod, metrics_exometer}
) or Grapherl ({metrics_mod, metrics_grapherl}
).
Be sure that's Folsom, Exometer or Grapherl is started before starting Kafe.
application:ensure_all_started(folsom).
application:ensure_all_started(kafe).
Metrics are disabled by default.
Kafe offers the following metrics :
Name | Type | Description |
---|---|---|
kafe_consumer.CONSUMER_GROUP.messages.fetch | gauge | Number of received messages on the last fetch for the CONSUMER_GROUP |
kafe_consumer.CONSUMER_GROUP.TOPIC.PARTITION.messages.fetch | gauge | Number of received messages on the last fetch for the {TOPIC, PARTITION} and CONSUMER_GROUP |
kafe_consumer.CONSUMER_GROUP.messages | counter | Total number of received messages for the CONSUMER_GROUP |
kafe_consumer.CONSUMER_GROUP.TOPIC.PARTITION.messages | counter | Total number of received messages for the {TOPIC, PARTITION} and CONSUMER_GROUP |
kafe_consumer.CONSUMER_GROUP.TOPIC.PARTITION.duration.fetch | gauge | Fetch duration (ms) per message, for the {TOPIC, PARTITION} and CONSUMER_GROUP |
kafe_consumer.CONSUMER_GROUP.TOPIC.PARTITION.pending_commits | gauge | Number of pending commits, for the {TOPIC, PARTITION} and CONSUMER_GROUP |
You can add a prefix to all metrics by adding a metrics_prefix
in the metrics
configuration :
{metrics, [
{metrics_mod, metrics_folsom},
{metrics_prefix, my_bot}
]}
Kafe use rebar3. So, you can use :
-
./rebar3 compile
to compile Kafe. -
./rebar3 eunit
to run tests. -
./rebar3 edoc
to build documentation. -
./rebar3 elixir generate_mix
to generatemix.exs
file. -
./rebar3 elixir generate_lib
to generate Elixir bindings.
See documentation
- Fork it ( https://github.com/botsunit/kafe/fork )
- Create your feature branch (
git checkout -b my-new-feature
) - Commit your changes (
git commit -am 'Add some feature'
) - Push to the branch (
git push origin my-new-feature
) - Create a new Pull Request
kafe is available for use under the following license, commonly known as the 3-clause (or "modified") BSD license:
Copyright (c) 2014, 2015 Finexkap
Copyright (c) 2015, G-Corp
Copyright (c) 2015, 2016 BotsUnit
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:* Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
- Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
- The name of the author may not be used to endorse or promote products derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE AUTHOR AS IS
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
kafe |
kafe_consumer |
kafe_consumer_subscriber |