Add kafka.structs docstrings (dpkp#2080)

Co-authored-by: MostafaElmenabawy <momenabawy@synapse-analytics.io>

kafka/structs.py

@@ -1,27 +1,82 @@
+""" Other useful structs """
 from __future__ import absolute_import
 
 from collections import namedtuple
 
 
-# Other useful structs
+"""A topic and partition tuple
+
+Keyword Arguments:
+    topic (str): A topic name
+    partition (int): A partition id
+"""
 TopicPartition = namedtuple("TopicPartition",
     ["topic", "partition"])
 
+
+"""A Kafka broker metadata used by admin tools.
+
+Keyword Arguments:
+    nodeID (int): The Kafka broker id.
+    host (str): The Kafka broker hostname.
+    port (int): The Kafka broker port.
+    rack (str): The rack of the broker, which is used to in rack aware
+                partition assignment for fault tolerance.
+    Examples: `RACK1`, `us-east-1d`. Default: None
+"""
 BrokerMetadata = namedtuple("BrokerMetadata",
     ["nodeId", "host", "port", "rack"])
 
+
+"""A topic partition metadata describing the state in the MetadataResponse.
+
+Keyword Arguments:
+    topic (str): The topic name of the partition this metadata relates to.
+    partition (int): The id of the partition this metadata relates to.
+    leader (int): The id of the broker that is the leader for the partition.
+    replicas (List[int]): The ids of all brokers that contain replicas of the
+                          partition.
+    isr (List[int]): The ids of all brokers that contain in-sync replicas of
+                     the partition.
+    error (KafkaError): A KafkaError object associated with the request for
+                        this partition metadata.
+"""
 PartitionMetadata = namedtuple("PartitionMetadata",
     ["topic", "partition", "leader", "replicas", "isr", "error"])
 
+
+"""The Kafka offset commit API
+
+The Kafka offset commit API allows users to provide additional metadata
+(in the form of a string) when an offset is committed. This can be useful
+(for example) to store information about which node made the commit,
+what time the commit was made, etc.
+
+Keyword Arguments:
+    offset (int): The offset to be committed
+    metadata (str): Non-null metadata
+"""
 OffsetAndMetadata = namedtuple("OffsetAndMetadata",
     # TODO add leaderEpoch: OffsetAndMetadata(offset, leaderEpoch, metadata)
     ["offset", "metadata"])
 
+
+"""An offset and timestamp tuple
+
+Keyword Arguments:
+    offset (int): An offset
+    timestamp (int): The timestamp associated to the offset
+"""
 OffsetAndTimestamp = namedtuple("OffsetAndTimestamp",
     ["offset", "timestamp"])
 
 
-# Define retry policy for async producer
-# Limit value: int >= 0, 0 means no retries
+"""Define retry policy for async producer
+
+Keyword Arguments:
+    Limit (int): Number of retries. limit >= 0, 0 means no retries
+    backoff_ms (int): Milliseconds to backoff.
+    retry_on_timeouts:
+"""
 RetryOptions = namedtuple("RetryOptions",
     ["limit", "backoff_ms", "retry_on_timeouts"])