dora-rs
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dora

 
			
			   
				 
					
						
						
							
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                <ol class="chapter"><li class="chapter-item expanded affix "><a href="introduction.html">Introduction</a></li><li class="spacer"></li><li class="chapter-item expanded affix "><li class="part-title">User Guide</li><li class="chapter-item expanded "><a href="installation.html"><strong aria-hidden="true">1.</strong> installation</a></li><li class="chapter-item expanded "><a href="getting-started.html"><strong aria-hidden="true">2.</strong> Getting started</a></li><li class="chapter-item expanded affix "><li class="part-title">Reference Guide</li><li class="chapter-item expanded "><a href="overview.html"><strong aria-hidden="true">3.</strong> Overview</a></li><li class="chapter-item expanded "><a href="dataflow-config.html"><strong aria-hidden="true">4.</strong> Dataflow Configuration</a></li><li class="chapter-item expanded "><a href="rust-api.html" class="active"><strong aria-hidden="true">5.</strong> Rust API</a></li><li class="chapter-item expanded "><a href="c-api.html"><strong aria-hidden="true">6.</strong> C API</a></li><li class="chapter-item expanded "><a href="python-api.html"><strong aria-hidden="true">7.</strong> Python API</a></li><li class="chapter-item expanded affix "><li class="part-title">Brainstorming Ideas</li><li class="chapter-item expanded "><a href="state-management.html"><strong aria-hidden="true">8.</strong> State Management</a></li><li class="chapter-item expanded "><a href="library-vs-framework.html"><strong aria-hidden="true">9.</strong> Library vs Framework</a></li><li class="chapter-item expanded "><a href="communication-layer.html"><strong aria-hidden="true">10.</strong> Middleware Layer Abstraction</a></li></ol>            </div>
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                        <h1 id="rust-api"><a class="header" href="#rust-api">Rust API</a></h1>
<h2 id="operator"><a class="header" href="#operator">Operator</a></h2>
<p>The operator API is a framework for you to implement. The implemented operator will be managed by <code>dora</code>. This framework enable us to make optimisation and provide advanced features. It is the recommended way of using <code>dora</code>.</p>
<p>An operator requires to be registered and implement the <code>DoraOperator</code> trait. It is composed of an <code>on_input</code> method that defines the behaviour of the operator when there is an input.</p>
<pre><pre class="playground"><code class="language-rust">
<span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span>use dora_operator_api::{register_operator, DoraOperator, DoraOutputSender, DoraStatus};

register_operator!(ExampleOperator);

#[derive(Debug, Default)]
struct ExampleOperator {
    time: Option&lt;String&gt;,
}

impl DoraOperator for ExampleOperator {
    fn on_input(
        &amp;mut self,
        id: &amp;str,
        data: &amp;[u8],
        output_sender: &amp;mut DoraOutputSender,
    ) -&gt; Result&lt;DoraStatus, ()&gt; {
<span class="boring">}
</span></code></pre></pre>
<h3 id="try-it-out"><a class="header" href="#try-it-out">Try it out!</a></h3>
<ul>
<li>Generate a new Rust library</li>
</ul>
<pre><code class="language-bash">cargo new example-operator --lib
</code></pre>
<p><code>Cargo.toml</code></p>
<pre><code class="language-toml">{{#include ../../examples/example-operator/Cargo.toml}}
</code></pre>
<p><code>src/lib.rs</code></p>
<pre><pre class="playground"><code class="language-rust">
<span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span>{{#include ../../examples/example-operator/src/lib.rs}}
<span class="boring">}
</span></code></pre></pre>
<ul>
<li>Build it:</li>
</ul>
<pre><code class="language-bash">cargo build --release
</code></pre>
<ul>
<li>Link it in your graph as:</li>
</ul>
<pre><code class="language-yaml">  - id: runtime-node
    operators:
      - id: op-1
        shared-library: ../../target/release/libexample_operator.so
        inputs:
          random: random/number
          time: timer/time
        outputs:
          - timestamped-random
</code></pre>
<p>This example can be found in <code>examples</code>.</p>
<h2 id="custom-node"><a class="header" href="#custom-node">Custom Node</a></h2>
<p>The custom node API allow you to integrate <code>dora</code> into your application. It allows you to retrieve input and send output in any fashion you want. </p>
<h4 id="doranodeinit_from_env"><a class="header" href="#doranodeinit_from_env"><code>DoraNode::init_from_env()</code></a></h4>
<p><code>DoraNode::init_from_env()</code> initiate a node from environment variables set by <code>dora-coordinator</code> </p>
<pre><pre class="playground"><code class="language-rust">
<span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span>let node = DoraNode::init_from_env().await?;
<span class="boring">}
</span></code></pre></pre>
<h4 id="inputs"><a class="header" href="#inputs"><code>.inputs()</code></a></h4>
<p><code>.inputs()</code> gives you a stream of input that you can access using <code>next()</code> on the input stream.</p>
<pre><pre class="playground"><code class="language-rust">
<span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span>let mut inputs = node.inputs().await?;
<span class="boring">}
</span></code></pre></pre>
<h4 id="send_outputoutput_id-data"><a class="header" href="#send_outputoutput_id-data"><code>.send_output(output_id, data)</code></a></h4>
<p><code>send_output</code> send data from the node.</p>
<pre><pre class="playground"><code class="language-rust">
<span class="boring">#![allow(unused)]
</span><span class="boring">fn main() {
</span>node.send_output(&amp;data_id, data.as_bytes()).await?;
<span class="boring">}
</span></code></pre></pre>
<h3 id="try-it-out-1"><a class="header" href="#try-it-out-1">Try it out!</a></h3>
<ul>
<li>Generate a new Rust binary (application):</li>
</ul>
<pre><code class="language-bash">cargo new source_timer
</code></pre>
<pre><code class="language-toml">[package]
name = &quot;source_timer&quot;
version = &quot;0.1.0&quot;
edition = &quot;2021&quot;
license = &quot;Apache-2.0&quot;

[dependencies]
dora-node-api = { path = &quot;../../apis/rust/node&quot; }
time = &quot;0.3.9&quot;
</code></pre>
<p><code>src/main.rs</code></p>
<pre><pre class="playground"><code class="language-rust">use dora_node_api::{self, config::DataId, DoraNode};
use std::time::Duration;
use time::OffsetDateTime;

#[tokio::main]
async fn main() -&gt; eyre::Result&lt;()&gt; {
    let operator = DoraNode::init_from_env().await?;

    let mut interval = tokio::time::interval(Duration::from_millis(20));

    let time_output = DataId::from(&quot;time&quot;.to_owned());
    for _ in 0..400 {
        interval.tick().await;
        let now = OffsetDateTime::now_utc().to_string();
        operator.send_output(&amp;time_output, now.as_bytes()).await?;
    }

    Ok(())
}
</code></pre></pre>
<ul>
<li>Link it in your graph as:</li>
</ul>
<pre><code class="language-yaml">  - id: timer
    custom:
      run: cargo run --release
      outputs:
        - time
</code></pre>

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