Brucke is a Inter-cluster bridge of kafka topics powered by Brod
Brucke bridges messages from upstream topic to downstream topic with configurable re-partitionning strategy and message filter/transform plugins
A brucke config file is a YAML file.
Config file path should be set in config_file variable of brucke app config, or via BRUCKE_CONFIG_FILE
OS env variable.
Cluster names and client names must comply to erlang atom syntax.
kafka_clusters:
kafka_cluster_1:
- "localhost:9092"
kafka_cluster_2:
- "kafka-1:9092"
- "kafka-2:9092"
brod_clients:
- client: brod_client_1
cluster: kafka_cluster_1
config: [] # optional
- client: brod_client_2 # example for SSL connection
cluster: kafka_cluster_1
config:
ssl: true
- client: brod_client_3 # example for SASL_SSL and custom certificates
cluster: kafka_cluster_1
config:
ssl:
# start with "priv/" or provide full path
cacertfile: priv/ssl/ca.crt
certfile: priv/ssl/client.crt
keyfile: priv/ssl/client.key
sasl:
# or 'plain' or 'scram_sha_256'
mechanism: scram_sha_512
username: brucke
password: secret
routes:
- upstream_client: brod_client_1
downstream_client: brod_client_1
upstream_topics:
- "topic_1"
downstream_topic: "topic_2"
repartitioning_strategy: strict_p2p
default_begin_offset: earliest # optional
filter_module: brucke_filter # optional
filter_init_arg: "" # optional
upstream_cg_id: example-consumer-group-1 # optional, build from cluster name otherwise
ssl
Either set totrue
or be specific about the cert/key files to usecacertfile
,certfile
andkeyfile
. In case the file paths start withpriv/
brucke
will look in applicationpriv
dir (i.e.code:priv_dir(brucke)
).sasl
Configure SASL authmechanism
,username
andpassword
for SASL PLAIN authentication.query_api_versions
Set tofalse
when connecting to kafka 0.9.x or earlier
See more configs in brod:start_client/4
API doc.
upstream_cg_id
identifies the consumer group which route workers (maybe distributed across different Erlang nodes) should join in, and commit offsets to.
Group IDs don't have to be unique, two or more routes may share the same group ID.
However, the same topic may not appear in two routes share the same group ID.
The default_begin_offset
route config is to tell upstream consumer from where to start streaming messsages.
Supported values are earliest
, latest
(default) or a kafka offset (integer) value.
This config is to tell brucke route worker from which offset it should start streaming messages for the first run.
In case of restart, brucke should continue from committed offset.
NOTE: Offsets committed to kafka may expire, in that case, brucke will fallback to this default being offset. NOTE: Currently this option is used for ALL partitions in upstream topic(s).
In case there is a need to discard committed offsets, pick a new group ID.
The Offset_commit_policy
specify how upstream consumer manages the offset per topic-partition.
Two values are available: commit_to_kafka_v2
or consumer_managed
.
when consumer_managed
is used, topic-partition offsets will be stored in dets (set). see "PATH to offsets DETS file".
default: commit_to_kafka_v2
NOTE: For compacted topics, strict_p2p is the only choice.
- key_hash: hash the message key to downstream partition number
- strict_p2p: strictly map the upstream partition number to downstream partition number, worker will refuse to start if upstream and downstream topic has different number of partitions
- random: randomly distribute upstream messages to downstream partitions
Depending on message format version in kafka broker, possible message formats from kafka are
- Version 0: key-value without timestamp (kafka prior to
0.10
) - Version 1: key-value with timestamp (since kafka
0.10
) - Version 2: key-value with headers and timestamp (since kafka
0.11
)
When downstream kafka supports lower version than upstream, unsupported fields are dropped. Otherwise messages are upgraded using default values as below:
- Local host's OS time is used as default timestamp if upstream message message has no
create
timestamp - Empty list
[]
is used as defaultheaders
field for downstream message if upstream message has noheaders
Implement brucke_filter
behaviour to have messages filtered and or transformed before produced to downstream topic.
If brucke
is packed standalone (i.e. not used as a dependency in a parent project), and the beam files for
brucke_filter
modules are installed elsewhere, configure filter_ebin_dirs
app env (sys.config),
or set system OS env variables BRUCKE_FILTER_EBIN_PATHS
.
compression
:no_compression
(defulat),gzip
orsnappy
max_partitions_per_group_member
: default = 12, Number of partitions one group member should work on.required_acks
:all
(default),leader
ornone
You can config brucke where to start consuming by providing the none empty 'Offsets DETS file' when brucke starts.
It should be set table and the record should be in following spec:
{ {GroupID :: binary() , Topic :: binary(), Partition :: non_neg_integer() }, Offset :: -1 | non_neg_integer() }.
offsets_dets_path
specify the PATH to the offsets dets file which is used by 'Offset Commit Policy'.
If file does not exists, brucke will create empty one and use it.
default: "/tmp/brucke_offsets.DETS"
Ratelimit the number of messages produced to downstream.
ratelimit_interval
defines the interval in milliseconds, default: 0 means disabled.
ratelimit_threshold
defines the threshold, set to 0 to pause.
You can change these two settings in realtime via restapi.
example:
Limit the msg rate of consumer group: group1
of cluster: clusterA
to 10 msgs/s:
POST /plugins/ratelimiter/clusterA/group1
{"interval": "100", "threshold", "1"}
If the following app config variables are set, brucke will send metrics to a configured graphite endpoint:
- graphite_root_path: a prefix for metrics, e.g "myservice"
- graphite_host: e.g. "localhost"
- graphite_port: e.g. 2003
Alternatively, you can use corresponding OS env variables:
- BRUCKE_GRAPHITE_ROOT_PATH
- BRUCKE_GRAPHITE_HOST
- BRUCKE_GRAPHITE_PORT
Generate a release and package it into an rpm package:
make rpm
Brucke package installs release and creates corresponding systemd service. Config files are in /etc/brucke, OS env can be set at /etc/sysconfig/brucke, logs are in /var/log/brucke.
Operating via systemctl:
systemctl start brucke
systemctl enable brucke
systemctl status brucke
Build:
make escript
Usage:
brucke <path/to/config.yml> [filter-module-ebin-dir ...]
Set BRUCKE_FILTER_MODULE_BEAM_DIRS
for extra filter module beam lookup.
For valid configs the validation command should silently exit with code 0.
Default port is 8080, customize via http_port
config option or via BRUCKE_HTTP_PORT
OS env variable.
GET /ping
Returns pong
if the application is up and running.
GET /healthcheck
Responds with status 200 if everything is OK, and 500 if something is not OK. Also returns healthy and unhealthy routes in response body in JSON format.
Example response:
{
"discarded": [
{
"downstream": {
"endpoints": [
{
"host": "localhost",
"port": 9192
}
],
"topic": "brucke-filter-test-downstream"
},
"options": {
"default_begin_offset": "earliest",
"filter_init_arg": [],
"filter_module": "brucke_test_filter",
"repartitioning_strategy": "strict_p2p"
},
"reason": [
"filter module brucke_test_filter is not found\nreason:embedded\n"
],
"upstream": {
"endpoints": [
{
"host": "localhost",
"port": 9092
}
],
"topics": [
"brucke-filter-test-upstream"
]
}
}
],
"healthy": [
{
"downstream": {
"endpoints": [
{
"host": "localhost",
"port": 9192
}
],
"topic": "brucke-basic-test-downstream"
},
"options": {
"consumer_config": {
"begin_offset": "earliest"
},
"filter_init_arg": [],
"filter_module": "brucke_filter",
"max_partitions_per_group_member": 12,
"producer_config": {
"compression": "no_compression"
},
"repartitioning_strategy": "strict_p2p"
},
"upstream": {
"endpoints": [
{
"host": "localhost",
"port": 9092
}
],
"topics": "brucke-basic-test-upstream"
}
},
{
"downstream": {
"endpoints": [
{
"host": "localhost",
"port": 9092
}
],
"topic": "brucke-test-topic-2"
},
"options": {
"consumer_config": {
"begin_offset": "earliest"
},
"filter_init_arg": [],
"filter_module": "brucke_filter",
"max_partitions_per_group_member": 12,
"producer_config": {
"compression": "no_compression"
},
"repartitioning_strategy": "strict_p2p"
},
"upstream": {
"endpoints": [
{
"host": "localhost",
"port": 9092
}
],
"topics": "brucke-test-topic-1"
}
},
{
"downstream": {
"endpoints": [
{
"host": "localhost",
"port": 9092
}
],
"topic": "brucke-test-topic-3"
},
"options": {
"consumer_config": {
"begin_offset": "latest"
},
"filter_init_arg": [],
"filter_module": "brucke_filter",
"max_partitions_per_group_member": 12,
"producer_config": {
"compression": "no_compression"
},
"repartitioning_strategy": "key_hash"
},
"upstream": {
"endpoints": [
{
"host": "localhost",
"port": 9092
}
],
"topics": "brucke-test-topic-2"
}
},
{
"downstream": {
"endpoints": [
{
"host": "localhost",
"port": 9192
}
],
"topic": "brucke-test-topic-1"
},
"options": {
"consumer_config": {
"begin_offset": "latest"
},
"filter_init_arg": [],
"filter_module": "brucke_filter",
"max_partitions_per_group_member": 12,
"producer_config": {
"compression": "no_compression"
},
"repartitioning_strategy": "random"
},
"upstream": {
"endpoints": [
{
"host": "localhost",
"port": 9192
}
],
"topics": "brucke-test-topic-3"
}
}
],
"status": "failing",
"unhealthy": []
}