CODEWITHSUNDEEP
javaapache-kafka
Daniel Alder
Daniel Alder

Reputation: 5372

Get a brokers list for Kafka AdminClient.describeLogDirs call

The API of AdminClient contains the method describeLogDirs which needs "a list of brokers" in both signatures. The expression in quotes is exactly what the javadoc tells about it - not more.

What do I have to provide as argument for this function? My first guess was a sequence starting by 0 or 1 to replication factor, but then I saw the following (unrelated) line in the logs of my application which showed me that I probably have to expect something like 1001.

13:47:11.931 [main] DEBUG o.a.k.c.consumer.internals.Fetcher - [Consumer clientId=myInstance-1725351556, groupId=] Sending READ_UNCOMMITTED IncrementalFetchRequest(toSend=(), toForget=(), implied=(myexample-0)) to broker example.com:9092 (id: 1001 rack: null)

I verified this by hard-coding 1001 for one run:

List<Integer> brokers = Collections.singletonList(1001);
DescribeLogDirsResult result = adminClient.describeLogDirs(brokers);

Now: how do I fill the variable brokers with live values from my kafka Client? (Producer and adminClient instances are available in my code)? I wasn't able to find any example code for this call.

Update (Solution): This is the final codeline which I'm using now:

List<Integer> brokers = adminClient.describeCluster().nodes().get().stream().map(Node::id).collect(Collectors.toList());

Upvotes: 2

Views: 1982

Answers (1)

Giorgos Myrianthous
Giorgos Myrianthous

Reputation: 39790

You can use describeCluster() in order to fetch node-specific details like host, port and id.

public abstract DescribeClusterResult describeCluster​(DescribeClusterOptions options)

Get information about the nodes in the cluster.

Parameters: options - The options to use when getting information about the cluster.

Returns: The DescribeClusterResult.

Example: 

Properties props = new Properties();
props.put("bootstrap.servers", "localhost:9092,localhost:9093");

AdminClient adminClient = AdminClient.create(props);
DescribeClusterResult describeClusterResult = adminClient.describeCluster();
Collection<Node> clusterDetails = describeClusterResult.nodes().get();

Upvotes: 1

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