在Rust消費者中消費多個Kafka主題

Question

我試圖使用Rust消費者從多個主題中讀取。這是代碼我現在有：

extern crate kafka; 
use kafka::client::KafkaClient; 
use kafka::consumer::Consumer; 
use kafka::utils; 
fn main(){ 
    let mut client = KafkaClient::new(vec!("localhost:9092".to_owned())); 
    let res = client.load_metadata_all(); 
    let topics = client.topic_partitions.keys().cloned().collect(); 
    let offsets = client.fetch_offsets(topics, -1); 
    for topic in &topics { 
    let mut con = Consumer::new(client, "test-consumer-group".to_owned(), "topic".to_owned()).partition(0); 
    let mut messagedata = 0; 
    for msg in con { 
     println!("{}", str::from_utf8(&msg.message).unwrap().to_string()); 
    } 
    } 
} 

下面

是錯誤：

src/main.rs:201:19: 201:25 error: use of moved value: `topics` [E0382] 
src/main.rs:201  for topic in &topics { 
            ^~~~~~ 
    note: in expansion of for loop expansion 
    src/main.rs:201:5: 210:6 note: expansion site 
    src/main.rs:167:40: 167:46 note: `topics` moved here because it has type `collections::vec::Vec<collections::string::String>`, which is non-copyable 
    src/main.rs:167  let offsets = client.fetch_offsets(topics, -1); 
                 ^~~~~~ 
    src/main.rs:203:37: 203:43 error: use of moved value: `client` [E0382] 
    src/main.rs:203  let mut con = Consumer::new(client, "test-consumer-group".to_owned(), "topicname".to_owned()).partition(0); 
                ^~~~~~ 
    note: in expansion of for loop expansion 
    src/main.rs:201:5: 210:6 note: expansion site 
    note: `client` was previously moved here because it has type  `kafka::client::KafkaClient`, which is non-copyable 
    error: aborting due to 2 previous errors 

爲了更好地解釋我的問題，在這裏只是一個話題我偏可行代碼：

let mut con = Consumer::new(client, "test-consumer-group".to_owned(), "testtopic".to_owned()).partition(0); 

for msg in con { 
    println!("{}", str::from_utf8(&msg.message).unwrap().to_string()); 
} 

我測試了fetch_message函數，它適用於多個主題，但是我有（msgs）的結果是Topicmessage，我不知道如何從TopicMessage獲取消息。

let msgs = client.fetch_messages_multi(vec!(utils::TopicPartitionOffset{ 
              topic: "topic1".to_string(), 
              partition: 0, 
              offset: 0 //from the begining 
              }, 
             utils::TopicPartitionOffset{ 
              topic: "topic2".to_string(), 
              partition: 0, 
              offset: 0 
             }, 
             utils::TopicPartitionOffset{ 
              topic: "topic3".to_string(), 
              partition: 0, 
              offset: 0 
             })); 
for msg in msgs{ 
    println!("{}", msg); 
} 

Answer 1

最後，我改變了這樣的代碼，它的工作原理。

let msgs = client.fetch_messages_multi(...).unwrap(); 
for msg in msgs{ 
    println!("{}", msg.message); 
}