Files
kafkaex-lag-exporter/lib/kafkaex_lag_exporter/kafka_utils.ex
2024-04-16 22:11:50 +02:00

113 lines
3.4 KiB
Elixir

# source code taken from https://github.com/reachfh/brod_group_subscriber_example
defmodule KafkaexLagExporter.KafkaUtils do
@behaviour KafkaexLagExporter.KafkaUtils.Behaviour
@moduledoc "Utility functions for dealing with Kafka"
alias KafkaexLagExporter.KafkaWrapper.Behaviour, as: KafkaWrapper
@default_client :client1
def connection, do: connection(@default_client)
@impl true
def connection(client) do
clients = Application.get_env(:brod, :clients)
config = clients[client]
endpoints = config[:endpoints] || [{~c"localhost", 9092}]
sock_opts =
case Keyword.fetch(config, :ssl) do
{:ok, ssl_opts} ->
[ssl: ssl_opts]
:error ->
[]
end
{endpoints, sock_opts}
end
@impl true
def get_consumer_group_names(endpoint) do
[{_, groups} | _] = KafkaWrapper.list_all_groups([endpoint], [])
groups
|> Enum.filter(fn {_, _, protocol} -> protocol === "consumer" end)
|> Enum.map(fn {_, group_name, _} -> group_name end)
end
@impl true
def get_consumer_group_info(endpoint, list \\ [], consumer_group_names) do
{:ok, group_descriptions} = KafkaWrapper.describe_groups(endpoint, list, consumer_group_names)
group_descriptions
|> Enum.flat_map(fn %{group_id: consumer_group, members: members} ->
get_member_info(consumer_group, members)
end)
end
@impl true
def lag(topic, consumer_group, client) do
offsets =
resolve_offsets(topic, client)
|> Enum.sort_by(fn {key, _value} -> key end)
committed_offsets =
fetch_committed_offsets(topic, consumer_group, client)
|> Enum.sort_by(fn {key, _value} -> key end)
for {{part, current}, {_, committed}} <- Enum.zip(offsets, committed_offsets) do
{part, current - committed}
end
end
@spec resolve_offsets(binary, atom) :: list({non_neg_integer, integer})
defp resolve_offsets(topic, client) do
{endpoints, sock_opts} = connection(client)
{:ok, partitions_count} = KafkaWrapper.get_partitions_count(client, topic)
for i <- Range.new(0, partitions_count - 1),
{:ok, offset} = KafkaWrapper.resolve_offset(endpoints, topic, i, :latest, sock_opts) do
{i, offset}
end
end
@spec fetch_committed_offsets(binary, binary, atom) ::
list({non_neg_integer, non_neg_integer})
defp fetch_committed_offsets(_topic, consumer_group, client) do
{endpoints, sock_opts} = connection(client)
{:ok, response} = KafkaWrapper.fetch_committed_offsets(endpoints, sock_opts, consumer_group)
for r <- response, pr <- r[:partitions] do
{pr[:partition_index], pr[:committed_offset]}
end
end
@spec get_member_info(
binary,
list(%{client_host: binary, member_assignment: binary, member_id: binary})
) ::
list(
{consumer_group :: binary, topics :: list(binary), consumer_id :: binary,
member_host :: binary}
)
defp get_member_info(consumer_group, members) do
members
|> Enum.map(fn %{
client_host: member_host,
member_assignment: member_assignment,
member_id: consumer_id
} ->
topics = KafkaexLagExporter.TopicNameParser.parse_topic_names(member_assignment)
{topics, consumer_id, member_host}
end)
|> Enum.map(fn {topics, consumer_id, member_host} ->
{consumer_group, topics, consumer_id, member_host}
end)
end
end