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<div class="section" id="understanding-the-client">
<span id="index-0"></span><span id="id1"></span>
<p>All communication with the <a class="reference internal" href="/wiki/display/ECFLOW/Glossary#term-ecflow-server"><em class="xref std std-term">ecflow_server</em></a> is done with <a class="reference internal" href="/wiki/display/ECFLOW/Glossary#term-ecflow-client"><em class="xref std std-term">ecflow_client</em></a></p>
<div class="line-block">
<div class="line">For any communication with the server, the client needs to know the machine</div>
<div class="line">where the server is running and the port on the server. There can be multiple</div>
<div class="line">servers running on the same machine, each with unique port numbers.</div>
</div>
<p>This tutorial will show examples of using the client via the shell and in a Python script.</p>
<div class="section" id="client-shell-interface">
<h2>Client Shell Interface<a class="headerlink" href="#client-shell-interface" title="Permalink to this headline">¶</a></h2>
<p>For a full list of available commands type:</p>
<div class="highlight-python"><pre>&gt; ecflow_client --help</pre>
</div>
<div class="line-block">
<div class="line">The <a class="reference internal" href="/wiki/display/ECFLOW/Glossary#term-ecflow-client"><em class="xref std std-term">ecflow_client</em></a> uses the following method of determining the <strong>host</strong> and <strong>port</strong></div>
</div>
<ul>
<li><p class="first">Default host and port is <strong>localhost</strong>:<strong>3141</strong></p>
</li>
<li><p class="first">These defaults are overridden by ECF_NODE and ECF_PORT environment variables</p>
</li>
<li><div class="first line-block">
<div class="line">This can be further overridden by using &#8211;port and &#8211;host options</div>
<div class="line">and can be used for any of shell level command shown with &#8211;help option.</div>
<div class="line">For example to ping a server on the command line we can use:</div>
</div>
<div class="highlight-python"><pre>&gt; ecflow_client --ping --host=machineX --port=4141</pre>
</div>
</li>
</ul>
</div>
<div class="section" id="client-python-interface">
<h2>Client Python Interface<a class="headerlink" href="#client-python-interface" title="Permalink to this headline">¶</a></h2>
<div class="line-block">
<div class="line">The functionality provided by <a class="reference internal" href="/wiki/display/ECFLOW/Glossary#term-ecflow-client"><em class="xref std std-term">ecflow_client</em></a> is also available via the <a class="reference internal" href="/wiki/display/ECFLOW/ecFlow+Python+Api#client-server-python-api"><em>client server python API</em></a>.</div>
</div>
<div class="line-block">
<div class="line">The python interface uses the same algorithm for determining the host and port,</div>
<div class="line">and allows the host and port to be set explicitly. See class <a class="reference internal" href="/wiki/display/ECFLOW/ecFlow+Python+Api#ecflow.Client" title="ecflow.Client"><tt class="xref py py-class docutils literal"><span class="pre">ecflow.Client</span></tt></a></div>
<div class="line">This is shown by the following python example:</div>
</div>
<div class="highlight-python"><div class="highlight"><pre><span class="c">#!/usr/bin/env python2.7</span>
<span class="kn">import</span> <span class="nn">ecflow</span>
   
<span class="k">try</span><span class="p">:</span>
    <span class="c"># When no arguments specified uses ECF_NODE and/or ECF_PORT,</span>
    <span class="c"># otherwise defaults to localhost:3141</span>
    <span class="n">ci</span> <span class="o">=</span> <span class="n">ecflow</span><span class="o">.</span><span class="n">Client</span><span class="p">()</span>
    <span class="n">ci</span><span class="o">.</span><span class="n">ping</span><span class="p">()</span>

    <span class="c"># Explicitly set host and port using the same client</span>
    <span class="c"># For alternative argument list see ecflow.Client.set_host_port() </span>
    <span class="n">ci</span><span class="o">.</span><span class="n">set_host_port</span><span class="p">(</span><span class="s">&quot;machineX:4141&quot;</span><span class="p">)</span>
    <span class="n">ci</span><span class="o">.</span><span class="n">ping</span><span class="p">()</span>
        
    <span class="c"># Create a new client, Explicitly setting host and port.</span>
    <span class="c"># For alternative argument list see ecflow.Client</span>
    <span class="n">ci</span> <span class="o">=</span> <span class="n">ecflow</span><span class="o">.</span><span class="n">Client</span><span class="p">(</span><span class="s">&quot;oetzi:3444&quot;</span><span class="p">)</span>  
    <span class="n">ci</span><span class="o">.</span><span class="n">ping</span><span class="p">()</span>  
           
<span class="k">except</span> <span class="ne">RuntimeError</span><span class="p">,</span> <span class="n">e</span><span class="p">:</span>
    <span class="k">print</span> <span class="s">&quot;ping failed: &quot;</span> <span class="o">+</span> <span class="nb">str</span><span class="p">(</span><span class="n">e</span><span class="p">);</span> 
</pre></div>
</div>
<p><strong>What to do:</strong></p>
<div class="line-block">
<div class="line">If your <a class="reference internal" href="/wiki/display/ECFLOW/Glossary#term-ecflow-server"><em class="xref std std-term">ecflow_server</em></a> was started with <strong>ecf_start.sh</strong> and you want to use the shell</div>
<div class="line">interface, then set ECF_NODE and ECF_PORT environment variables</div>
</div>
</div>
</div>