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Dave Syer
2015-08-26 18:27:57 +00:00
parent 3fcbd96814
commit 81fd23b138
1 changed files with 3 additions and 45 deletions
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spring-cloud-stream.html
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@@ -442,7 +442,7 @@ public class TimerSource {
private String format;
@Bean
@InboundChannelAdapter(value = Source.OUTPUT, autoStartup = "false", poller = @Poller(fixedDelay = "${fixedDelay}", maxMessagesPerPoll = "1"))
@InboundChannelAdapter(value = Source.OUTPUT, poller = @Poller(fixedDelay = "${fixedDelay}", maxMessagesPerPoll = "1"))
public MessageSource<String> timerMessageSource() {
return () -> new GenericMessage<>(new SimpleDateFormat(format).format(new Date()));
}
@@ -451,20 +451,6 @@ public class TimerSource {
</div>
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<div class="paragraph">
<p>The <code>application.yml</code> has the mapping from channel names to external broker handles (queues, topics, routing keys, etc. depending on the broker), e.g.</p>
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<div class="listingblock">
<div class="title">application.yml</div>
<div class="content">
<pre>---
spring:
cloud:
stream:
bindings:
output: ${spring.application.name:ticker}</pre>
</div>
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<div class="paragraph">
<p><code>@EnableModule</code> is parameterized by an interface (in this case <code>Source</code>) which declares input and output channels. <code>Source</code>, <code>Sink</code> and <code>Processor</code> are provided off the shelf, but you can define others. Here&#8217;s the definition of <code>Source</code></p>
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@@ -515,7 +501,7 @@ In this case there is only one <code>Source</code> in the application context so
<h2 id="_multiple_input_or_output_channels">Multiple Input or Output Channels</h2>
<div class="sectionbody">
<div class="paragraph">
<p>A module can have multiple input or output channels all defined either as <code>@Input</code> and <code>@Output</code> methods in an interface (preferrable) or as bean definitions. Instead of just one channel named "input" or "output" you can add multiple <code>MessageChannel</code> methods annotated <code>@Input</code> or <code>@Output</code> and the names are converted to external channel names on the broker. The external channel names can be specified as properties that consist of the channel names prefixed with <code>spring.cloud.stream.bindings</code> (e.g. <code>spring.cloud.stream.bindings.input</code> or <code>spring.cloud.stream.bindings.output</code>). External channel names can have a channel type as a colon-separated prefix, and the semantics of the external bus channel changes accordingly (a tap is like a topic). For example, you can have two <code>MessageChannels</code> called "output" and "foo" in a module with <code>spring.cloud.stream.bindings.output=bar</code> and <code>spring.cloud.stream.bindings.foo=topic:foo</code>, and the result is 2 external channels called "bar" and "topic:foo".</p>
<p>A module can have multiple input or output channels all defined either as <code>@Input</code> and <code>@Output</code> methods in an interface (preferrable) or as bean definitions. Instead of just one channel named "input" or "output" you can add multiple <code>MessageChannel</code> methods annotated <code>@Input</code> or <code>@Output</code> and the names are converted to external channel names on the broker. The external channel names can be specified as properties that consist of the channel names prefixed with <code>spring.cloud.stream.bindings</code> (e.g. <code>spring.cloud.stream.bindings.input</code> or <code>spring.cloud.stream.bindings.output</code>). External channel names can have a channel type as a colon-separated prefix, and the semantics of the external bus channel changes accordingly. For example, you can have two <code>MessageChannels</code> called "output" and "foo" in a module with <code>spring.cloud.stream.bindings.output=bar</code> and <code>spring.cloud.stream.bindings.foo=topic:foo</code>, and the result is 2 external channels called "bar" and "topic:foo".</p>
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@@ -593,38 +579,10 @@ The main set of samples are "vanilla" in the sense that they are not deployable
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<div class="sect1">
<h2 id="_taps">Taps</h2>
<div class="sectionbody">
<div class="paragraph">
<p>All output channels can be also tapped so you can also attach a module to a pub-sub endpoint and listen to the tap if you know the module metadata. To tap an existing vanilla module you need to know its <code>outputChannelName</code> and the tap name is then <code>tap:&lt;outputChannelName&gt;</code>, so you can listen to it on an input channel named <code>topic.tap:&lt;outputChannelName&gt;</code>. The tap is only active if you explicitly ask for it: you can do that by POSTing to the HTTP endpoint <code>/taps/&lt;channelName&gt;</code> (where the channel name can be the internal or external name, e.g. "output" or the external name mapped to the output channel).</p>
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<div class="paragraph">
<p>To tap an existing output channel in an XD module you just need to know its group, name and index, e.g.</p>
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<div class="listingblock">
<div class="content">
<pre class="highlight"><code>spring:
cloud:
stream:
group: tocktap
name: logger
index: 0
tap:
group: testtock
name: ticker
index: 0</code></pre>
</div>
</div>
<div class="paragraph">
<p>The <code>spring.cloud.stream.tap</code> section tells the module runner which topic you want to subscribe to. It creates a new group (a tap can&#8217;t be in the same group as the one it is tapping) and starts a new index count, in case anyone wants to listen downstream.</p>
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<div id="footer">
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Last updated 2015-08-26 09:27:33 UTC
Last updated 2015-08-26 18:25:42 UTC
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