差異處
這裏顯示兩個版本的差異處。
java:apache_camel:aggregator:helloworld [2019/03/17 21:55] tony [Unit Test] |
java:apache_camel:aggregator:helloworld [2023/06/25 09:48] |
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- | ====== Camel - Aggregator Hello World ====== | ||
- | ===== Introduction ===== | ||
- | Camel Aggregator提供開發人員能夠將大量訊息合成一個的功能。假設你的系統會接受外來通知,並將內容寫進資料庫中;一次連線寫一筆資料會比較快,還是透過一次連線寫入五筆資料快呢? 正常來說,一次連線寫入五筆同屬性資料會是比較快的。它與[[java:apache_camel:throttler:helloworld|Throttler]]的最大區別在於,Throttler限制了client的請求,而Aggreator則是收集起來一次請求。因此,如果使用Aggreator,你的程式必須要有對應的處理方式。\\ | ||
- | \\ | ||
- | 我將透過HTTP GET請求/events/{id}做為範例,說明如何使用Aggregator去將單位時間內的請求,以{id}去分組並Aggredate成各別分組訊息。本篇文章中使用到兩個RouteBuilder,分別為RestRouteBuilder與AggregatorGroupRouteBuilder。RestRouteBuilder負責REST核心相關設定,可參考[[java:apache_camel:throttler:helloworld|先前文章]]。接下來直接說明AggregatorGroupRouteBuilder。 | ||
- | ===== AggregatorGroupRouteBuilder ===== | ||
- | <code java> | ||
- | package org.tonylin.practice.camel.aggregator; | ||
- | import static com.google.common.base.Preconditions.checkState; | ||
- | |||
- | import org.apache.camel.builder.RouteBuilder; | ||
- | import org.apache.camel.processor.aggregate.GroupedExchangeAggregationStrategy; | ||
- | |||
- | public class AggregatorGroupRouteBuilder extends RouteBuilder { | ||
- | |||
- | private final static String GET_EVENTS = "GET_EVENTS"; | ||
- | |||
- | private Object eventHandler; | ||
- | private int period = 500; | ||
- | |||
- | public AggregatorGroupRouteBuilder(Object eventHandler) { | ||
- | this.eventHandler = eventHandler; | ||
- | |||
- | } | ||
- | |||
- | public void setPeriod(int period) { | ||
- | this.period = period; | ||
- | } | ||
- | |||
- | @Override | ||
- | public void configure() throws Exception { | ||
- | checkState(eventHandler!=null, "Can't find eventHandler"); | ||
- | |||
- | rest("/events/{id}").get().route().id(GET_EVENTS) | ||
- | .aggregate(new GroupedExchangeAggregationStrategy()) | ||
- | .header("id") | ||
- | .completionInterval(period) | ||
- | .bean(eventHandler).endRest(); | ||
- | } | ||
- | } | ||
- | </code> | ||
- | 以下是在configure中的幾個重點: | ||
- | * aggregate(new GroupedExchangeAggregationStrategy()): 使用GroupedExchangeAggregationStrategy去做aggregate,aggregate的內容為Exchange。如果有任何條件限制,要以Exchange去操作。 | ||
- | * header("id"): 與aggregate一起使用,代表以header id去分組,在這裡就是屬於event的id。 | ||
- | * completionInterval(period): 做aggregate的單位時間。 | ||
- | * bean(eventHandler): 請求的處理者,必須要有能力處理aggregate後的訊息。 | ||
- | Camel Aggregator提供了很多細部操作,你也可以根據自身需求做AggregationStrategy,這部分以後有機會再分享。接下來讓我們透過單元測試展示效果。 | ||
- | ===== Unit Test ===== | ||
- | 測試有兩個目標,testGroupedExchange用以確認aggregate group後的結果,另外一個testCompletionInterval則是確認單位時間設定的作用。以下為程式碼主要結構,主要測試程式碼稍後做說明: | ||
- | <code java> | ||
- | package org.tonylin.practice.camel.aggregator; | ||
- | |||
- | import static com.google.common.base.Preconditions.checkState; | ||
- | |||
- | import java.util.Arrays; | ||
- | import java.util.List; | ||
- | import java.util.Map; | ||
- | import java.util.concurrent.ConcurrentHashMap; | ||
- | import java.util.concurrent.CountDownLatch; | ||
- | import java.util.concurrent.TimeUnit; | ||
- | import java.util.stream.Collectors; | ||
- | |||
- | import org.apache.camel.Exchange; | ||
- | import org.apache.camel.Handler; | ||
- | import org.apache.camel.RoutesBuilder; | ||
- | import org.apache.camel.test.junit4.CamelTestSupport; | ||
- | import org.apache.http.HttpResponse; | ||
- | import org.apache.http.client.HttpClient; | ||
- | import org.apache.http.client.methods.HttpGet; | ||
- | import org.apache.http.impl.client.HttpClientBuilder; | ||
- | import org.junit.Test; | ||
- | import org.tonylin.practice.camel.rest.RestRouteBuilder; | ||
- | |||
- | public class AggregatorGroupRouteBuilderTest extends CamelTestSupport { | ||
- | |||
- | private RestHandler hander = new RestHandler(); | ||
- | |||
- | private HttpClient client = HttpClientBuilder.create().build(); | ||
- | |||
- | @Override | ||
- | protected RoutesBuilder[] createRouteBuilders() throws Exception { | ||
- | AggregatorGroupRouteBuilder aggregatorGroupRouteBuilder = new AggregatorGroupRouteBuilder(hander); | ||
- | aggregatorGroupRouteBuilder.setPeriod(500); | ||
- | |||
- | return new RoutesBuilder[] { | ||
- | new RestRouteBuilder(), | ||
- | aggregatorGroupRouteBuilder | ||
- | }; | ||
- | } | ||
- | |||
- | @Test | ||
- | public void testGroupedExchange() throws Exception { | ||
- | // skip | ||
- | } | ||
- | @Test | ||
- | public void testCompletionInterval() throws Exception { | ||
- | // skip | ||
- | } | ||
- | } | ||
- | </code> | ||
- | 此測試中的RestHandler程式碼如下,它會透過GROUPED_EXCHANGE取得aggregator處理後的內容,並根據header id儲存到map中,供測試程式碼做assertion。除此之外,在這裡使用CountDownLatch了去確認有收到預期訊息數量: | ||
- | <code java> | ||
- | public static class RestHandler { | ||
- | private Map<String, List<Exchange>> requestData = new ConcurrentHashMap<String, List<Exchange>>(); | ||
- | private CountDownLatch countDownLatch; | ||
- | |||
- | @SuppressWarnings("unchecked") | ||
- | @Handler | ||
- | public void handle(Exchange exchange) { | ||
- | List<Exchange> groupExchanges = exchange.getProperty(Exchange.GROUPED_EXCHANGE, List.class); | ||
- | String id = groupExchanges.get(0).getIn().getHeader("id", String.class); | ||
- | requestData.put(id, groupExchanges); | ||
- | |||
- | if( countDownLatch != null ) | ||
- | countDownLatch.countDown(); | ||
- | } | ||
- | |||
- | public Map<String, List<Exchange>> getRequestData(){ | ||
- | return requestData; | ||
- | } | ||
- | |||
- | public void expectNum(int num) { | ||
- | countDownLatch = new CountDownLatch(num); | ||
- | } | ||
- | |||
- | public void waitCompletion(int timeout) throws InterruptedException { | ||
- | checkState(countDownLatch!=null); | ||
- | countDownLatch.await(timeout, TimeUnit.MILLISECONDS); | ||
- | } | ||
- | |||
- | public void clear() { | ||
- | requestData.clear(); | ||
- | } | ||
- | } | ||
- | </code> | ||
- | 首先讓我說明testGroupedExchange。測試程式碼中,送了四個訊息,其中包含了三組不同id;這樣的請求,我們預期RestHandler中,總共會收到三組訊息,其中id 123那組,應包含兩個訊息: | ||
- | <code java> | ||
- | private HttpResponse requestWithEventId(String id) { | ||
- | try { | ||
- | HttpGet httpGet = new HttpGet("http://localhost:8080/events/" + id); | ||
- | return client.execute(httpGet); | ||
- | } catch( Exception e ) { | ||
- | throw new RuntimeException(e); | ||
- | } | ||
- | } | ||
- | |||
- | @Test | ||
- | public void testGroupedExchange() throws Exception { | ||
- | // given request event id | ||
- | List<String> eventIds = Arrays.asList("123", "123", "456", "789"); | ||
- | hander.expectNum(3); | ||
- | |||
- | // when | ||
- | List<HttpResponse> responses = eventIds.parallelStream().map(this::requestWithEventId).collect(Collectors.toList()); | ||
- | |||
- | // then | ||
- | responses.forEach(response->{ | ||
- | assertEquals(200, response.getStatusLine().getStatusCode()); | ||
- | }); | ||
- | |||
- | hander.waitCompletion(1000); | ||
- | |||
- | Map<String, List<Exchange>> requestData = hander.getRequestData(); | ||
- | assertEquals(3, requestData.size()); | ||
- | assertEquals(2, requestData.get("123").size()); | ||
- | assertEquals(1, requestData.get("456").size()); | ||
- | assertEquals(1, requestData.get("789").size()); | ||
- | } | ||
- | </code> | ||
- | 接著是testCompletionInterval,這裡我直接透過請求相同id兩次,並分兩輪送出。這樣做可以確認aggregator有做到根據completionInterval的分批效果: | ||
- | <code java> | ||
- | private void requestTwiceWithId(String id) throws Exception { | ||
- | // request event {id} twice | ||
- | List<String> eventIds = Arrays.asList(id, id); | ||
- | hander.expectNum(1); | ||
- | List<HttpResponse> responses = eventIds.parallelStream().map(this::requestWithEventId).collect(Collectors.toList()); | ||
- | responses.forEach(response->{ | ||
- | assertEquals(200, response.getStatusLine().getStatusCode()); | ||
- | }); | ||
- | |||
- | hander.waitCompletion(1000); | ||
- | |||
- | // confirm request result | ||
- | Map<String, List<Exchange>> requestData = hander.getRequestData(); | ||
- | assertEquals(1, requestData.size()); | ||
- | assertEquals(2, requestData.get("123").size()); | ||
- | |||
- | // clear first request data | ||
- | hander.clear(); | ||
- | assertTrue(hander.getRequestData().isEmpty()); | ||
- | } | ||
- | |||
- | @Test | ||
- | public void testCompletionInterval() throws Exception { | ||
- | requestTwiceWithId("123"); | ||
- | requestTwiceWithId("123"); | ||
- | } | ||
- | </code> | ||
- | |||
- | |||
- | ===== Reference ===== | ||
- | * [[http://camel.apache.org/aggregator.html|Camel - Aggregator]] | ||
- | |||
- | ===== ===== | ||
- | ---- | ||
- | \\ | ||
- | ~~DISQUS~~ |