fluent-plugin-kafka, a plugin for Fluentd
A fluentd plugin to both consume and produce data for Apache Kafka.
TODO: Also, I need to write tests
Add this line to your application's Gemfile:
gem 'fluent-plugin-kafka'
And then execute:
$ bundle
Or install it yourself as:
$ gem install fluent-plugin-kafka --no-document
If you want to use zookeeper related parameters, you also need to install zookeeper gem. zookeeper gem includes native extension, so development tools are needed, e.g. ruby-devel, gcc, make and etc.
- Ruby 2.1 or later
- Input plugins work with kafka v0.9 or later
- Output plugins work with kafka v0.8 or later
- ssl_ca_cert
- ssl_client_cert
- ssl_client_cert_key
- ssl_ca_certs_from_system
Set path to SSL related files. See Encryption and Authentication using SSL for more detail.
- principal
- keytab
Set principal and path to keytab for SASL/GSSAPI authentication. See Authentication using SASL for more details.
- username
- password
- scram_mechanism
- sasl_over_ssl
Set username, password, scram_mechanism and sasl_over_ssl for SASL/Plain or Scram authentication. See Authentication using SASL for more details.
Consume events by single consumer.
<source>
@type kafka
brokers <broker1_host>:<broker1_port>,<broker2_host>:<broker2_port>,..
topics <listening topics(separate with comma',')>
format <input text type (text|json|ltsv|msgpack)> :default => json
message_key <key (Optional, for text format only, default is message)>
add_prefix <tag prefix (Optional)>
add_suffix <tag suffix (Optional)>
# Optionally, you can manage topic offset by using zookeeper
offset_zookeeper <zookeer node list (<zookeeper1_host>:<zookeeper1_port>,<zookeeper2_host>:<zookeeper2_port>,..)>
offset_zk_root_node <offset path in zookeeper> default => '/fluent-plugin-kafka'
# ruby-kafka consumer options
max_bytes (integer) :default => nil (Use default of ruby-kafka)
max_wait_time (integer) :default => nil (Use default of ruby-kafka)
min_bytes (integer) :default => nil (Use default of ruby-kafka)
</source>
Supports a start of processing from the assigned offset for specific topics.
<source>
@type kafka
brokers <broker1_host>:<broker1_port>,<broker2_host>:<broker2_port>,..
format <input text type (text|json|ltsv|msgpack)>
<topic>
topic <listening topic>
partition <listening partition: default=0>
offset <listening start offset: default=-1>
</topic>
<topic>
topic <listening topic>
partition <listening partition: default=0>
offset <listening start offset: default=-1>
</topic>
</source>
See also ruby-kafka README for more detailed documentation about ruby-kafka.
Consuming topic name is used for event tag. So when the target topic name is app_event, the tag is app_event. If you want to modify tag, use add_prefix or add_suffix parameters. With add_prefix kafka, the tag is kafka.app_event.
Consume events by kafka consumer group features..
<source>
@type kafka_group
brokers <broker1_host>:<broker1_port>,<broker2_host>:<broker2_port>,..
consumer_group <consumer group name, must set>
topics <listening topics(separate with comma',')>
format <input text type (text|json|ltsv|msgpack)> :default => json
message_key <key (Optional, for text format only, default is message)>
add_prefix <tag prefix (Optional)>
add_suffix <tag suffix (Optional)>
retry_emit_limit <Wait retry_emit_limit x 1s when BuffereQueueLimitError happens. The default is nil and it means waiting until BufferQueueLimitError is resolved>
use_record_time <If true, replace event time with contents of 'time' field of fetched record>
time_format <string (Optional when use_record_time is used)>
# ruby-kafka consumer options
max_bytes (integer) :default => 1048576
max_wait_time (integer) :default => nil (Use default of ruby-kafka)
min_bytes (integer) :default => nil (Use default of ruby-kafka)
offset_commit_interval (integer) :default => nil (Use default of ruby-kafka)
offset_commit_threshold (integer) :default => nil (Use default of ruby-kafka)
fetcher_max_queue_size (integer) :default => nil (Use default of ruby-kafka)
start_from_beginning (bool) :default => true
</source>
See also ruby-kafka README for more detailed documentation about ruby-kafka options.
Consuming topic name is used for event tag. So when the target topic name is app_event, the tag is app_event. If you want to modify tag, use add_prefix or add_suffix parameter. With add_prefix kafka, the tag is kafka.app_event.
This plugin uses ruby-kafka producer for writing data. This plugin works with recent kafka versions. This plugin is for v0.12. If you use v1, see kafka2.
<match app.**>
@type kafka_buffered
# Brokers: you can choose either brokers or zookeeper. If you are not familiar with zookeeper, use brokers parameters.
brokers <broker1_host>:<broker1_port>,<broker2_host>:<broker2_port>,.. # Set brokers directly
zookeeper <zookeeper_host>:<zookeeper_port> # Set brokers via Zookeeper
zookeeper_path <broker path in zookeeper> :default => /brokers/ids # Set path in zookeeper for kafka
topic_key (string) :default => 'topic'
partition_key (string) :default => 'partition'
partition_key_key (string) :default => 'partition_key'
message_key_key (string) :default => 'message_key'
default_topic (string) :default => nil
default_partition_key (string) :default => nil
default_message_key (string) :default => nil
output_data_type (json|ltsv|msgpack|attr:<record name>|<formatter name>) :default => json
output_include_tag (bool) :default => false
output_include_time (bool) :default => false
exclude_topic_key (bool) :default => false
exclude_partition_key (bool) :default => false
get_kafka_client_log (bool) :default => false
# See fluentd document for buffer related parameters: http://docs.fluentd.org/articles/buffer-plugin-overview
# ruby-kafka producer options
max_send_retries (integer) :default => 1
required_acks (integer) :default => -1
ack_timeout (integer) :default => nil (Use default of ruby-kafka)
compression_codec (gzip|snappy) :default => nil (No compression)
kafka_agg_max_bytes (integer) :default => 4096
kafka_agg_max_messages (integer) :default => nil (No limit)
max_send_limit_bytes (integer) :default => nil (No drop)
discard_kafka_delivery_failed (bool) :default => false (No discard)
monitoring_list (array) :default => []
</match>
<formatter name> of output_data_type uses fluentd's formatter plugins. See formatter article.
ruby-kafka sometimes returns Kafka::DeliveryFailed error without good information.
In this case, get_kafka_client_log is useful for identifying the error cause.
ruby-kafka's log is routed to fluentd log so you can see ruby-kafka's log in fluentd logs.
Supports following ruby-kafka's producer options.
- max_send_retries - default: 1 - Number of times to retry sending of messages to a leader.
- required_acks - default: -1 - The number of acks required per request. If you need flush performance, set lower value, e.g. 1, 2.
- ack_timeout - default: nil - How long the producer waits for acks. The unit is seconds.
- compression_codec - default: nil - The codec the producer uses to compress messages.
- kafka_agg_max_bytes - default: 4096 - Maximum value of total message size to be included in one batch transmission.
- kafka_agg_max_messages - default: nil - Maximum number of messages to include in one batch transmission.
- max_send_limit_bytes - default: nil - Max byte size to send message to avoid MessageSizeTooLarge. For example, if you set 1000000(message.max.bytes in kafka), Message more than 1000000 byes will be dropped.
- discard_kafka_delivery_failed - default: false - discard the record where Kafka::DeliveryFailed occurred
- monitoring_list - default: [] - library to be used to monitor. statsd and datadog are supported
If you want to know about detail of monitoring, see also https://github.com/zendesk/ruby-kafka#monitoring
See also Kafka::Client for more detailed documentation about ruby-kafka.
This plugin supports compression codec "snappy" also. Install snappy module before you use snappy compression.
$ gem install snappy --no-document
snappy gem uses native extension, so you need to install several packages before. On Ubuntu, need development packages and snappy library.
$ sudo apt-get install build-essential autoconf automake libtool libsnappy-dev
On CentOS 7 installation is also necessary.
$ sudo yum install gcc autoconf automake libtool snappy-devel
Messages will be assigned a partition at random as default by ruby-kafka, but messages with the same partition key will always be assigned to the same partition by setting default_partition_key in config file.
If key name partition_key_key exists in a message, this plugin set the value of partition_key_key as key.
| default_partition_key | partition_key_key | behavior |
|---|---|---|
| Not set | Not exists | All messages are assigned a partition at random |
| Set | Not exists | All messages are assigned to the specific partition |
| Not set | Exists | Messages which have partition_key_key record are assigned to the specific partition, others are assigned a partition at random |
| Set | Exists | Messages which have partition_key_key record are assigned to the specific partition with partition_key_key, others are assigned to the specific partition with default_parition_key |
If key name message_key_key exists in a message, this plugin publishes the value of message_key_key to kafka and can be read by consumers. Same message key will be assigned to all messages by setting default_message_key in config file. If message_key_key exists and if partition_key_key is not set explicitly, messsage_key_key will be used for partitioning.
This plugin is for fluentd v1.0 or later. This will be out_kafka plugin in the future.
<match app.**>
@type kafka2
brokers <broker1_host>:<broker1_port>,<broker2_host>:<broker2_port>,.. # Set brokers directly
topic_key (string) :default => 'topic'
partition_key (string) :default => 'partition'
partition_key_key (string) :default => 'partition_key'
message_key_key (string) :default => 'message_key'
default_topic (string) :default => nil
default_partition_key (string) :default => nil
default_message_key (string) :default => nil
exclude_topic_key (bool) :default => false
exclude_partition_key (bool) :default => false
get_kafka_client_log (bool) :default => false
use_default_for_unknown_topic (bool) :default => false
<format>
@type (json|ltsv|msgpack|attr:<record name>|<formatter name>) :default => json
</format>
# Optional. See https://docs.fluentd.org/v1.0/articles/inject-section
<inject>
tag_key tag
time_key time
</inject>
# See fluentd document for buffer related parameters: http://docs.fluentd.org/articles/buffer-plugin-overview
# Buffer chunk key should be same with topic_key. If value is not found in the record, default_topic is used.
<buffer topic>
flush_interval 10s
</buffer>
# ruby-kafka producer options
max_send_retries (integer) :default => 1
required_acks (integer) :default => -1
ack_timeout (integer) :default => nil (Use default of ruby-kafka)
compression_codec (gzip|snappy) :default => nil (No compression)
</match>
This plugin uses ruby-kafka producer for writing data. For performance and reliability concerns, use kafka_bufferd output instead. This is mainly for testing.
<match app.**>
@type kafka
# Brokers: you can choose either brokers or zookeeper.
brokers <broker1_host>:<broker1_port>,<broker2_host>:<broker2_port>,.. # Set brokers directly
zookeeper <zookeeper_host>:<zookeeper_port> # Set brokers via Zookeeper
zookeeper_path <broker path in zookeeper> :default => /brokers/ids # Set path in zookeeper for kafka
default_topic (string) :default => nil
default_partition_key (string) :default => nil
default_message_key (string) :default => nil
output_data_type (json|ltsv|msgpack|attr:<record name>|<formatter name>) :default => json
output_include_tag (bool) :default => false
output_include_time (bool) :default => false
exclude_topic_key (bool) :default => false
exclude_partition_key (bool) :default => false
# ruby-kafka producer options
max_send_retries (integer) :default => 1
required_acks (integer) :default => -1
ack_timeout (integer) :default => nil (Use default of ruby-kafka)
compression_codec (gzip|snappy) :default => nil
max_buffer_size (integer) :default => nil (Use default of ruby-kafka)
max_buffer_bytesize (integer) :default => nil (Use default of ruby-kafka)
</match>
This plugin also supports ruby-kafka related parameters. See Buffered output plugin section.
This plugin uses rdkafka instead of ruby-kafka for ruby client.
You need to install rdkafka gem.
# rdkafka is C extension library so need development tools like ruby-devel, gcc and etc
$ gem install rdkafka --no-document
rdkafka2 is for fluentd v1.0 or later.
<match app.**>
@type rdkafka2
brokers <broker1_host>:<broker1_port>,<broker2_host>:<broker2_port>,.. # Set brokers directly
topic_key (string) :default => 'topic'
default_topic (string) :default => nil
partition_key (string) :default => 'partition'
partition_key_key (string) :default => 'partition_key'
message_key_key (string) :default => 'message_key'
default_topic (string) :default => nil
default_partition_key (string) :default => nil
default_message_key (string) :default => nil
exclude_topic_key (bool) :default => false
exclude_partition_key (bool) :default => false
<format>
@type (json|ltsv|msgpack|attr:<record name>|<formatter name>) :default => json
</format>
# Optional. See https://docs.fluentd.org/v1.0/articles/inject-section
<inject>
tag_key tag
time_key time
</inject>
# See fluentd document for buffer section parameters: https://docs.fluentd.org/v1.0/articles/buffer-section
# Buffer chunk key should be same with topic_key. If value is not found in the record, default_topic is used.
<buffer topic>
flush_interval 10s
</buffer>
# You can set any rdkafka configuration via this parameter: https://github.com/edenhill/librdkafka/blob/master/CONFIGURATION.md
rdkafka_options {
"log_level" : 7
}
</match>
If you use v0.12, use rdkafka instead.
<match kafka.**>
@type rdkafka
default_topic kafka
flush_interval 1s
output_data_type json
rdkafka_options {
"log_level" : 7
}
</match>
- Fork it
- Create your feature branch (
git checkout -b my-new-feature) - Commit your changes (
git commit -am 'Added some feature') - Push to the branch (
git push origin my-new-feature) - Create new Pull Request