<div  id="understanding-the-client">
<span id="index-0"></span><span id="id1"></span>
<p>All communication with the <a  href="/wiki/display/ECFLOW/Glossary#term-ecflow-server"><em >ecflow_server</em></a> is done with <a  href="/wiki/display/ECFLOW/Glossary#term-ecflow-client"><em >ecflow_client</em></a></p>
<div >
<div >For any communication with the server, the client needs to know the machine</div>
<div >where the server is running, and the port on the server. There can be multiple</div>
<div >server&#8217;s running on the same machine, hence the port number is important.</div>
</div>
<p>This tutorial will show examples of using the client at the shell and in a python script.</p>
<div  id="client-shell-interface">
<h2>Client Shell Interface<a  href="#client-shell-interface" title="Permalink to this headline">¶</a></h2>
<p>For a full list of available commands type:</p>
<div ><pre>&gt; ecflow_client --help</pre>
</div>
<div >
<div >The <a  href="/wiki/display/ECFLOW/Glossary#term-ecflow-client"><em >ecflow_client</em></a> uses the following method of determining the <strong>host</strong> and <strong>port</strong></div>
</div>
<ul>
<li><p >Default host and port is <strong>localhost</strong>:<strong>3141</strong></p>
</li>
<li><p >These defaults are overridden by ECF_NODE and ECF_PORT environment variables</p>
</li>
<li><div >
<div >This can be further overridden by using &#8211;port and &#8211;host options</div>
<div >and can be used for any of shell level command shown with &#8211;help option.</div>
<div >For example to ping a server on the command line we can use:</div>
</div>
<div ><pre>&gt; ecflow_client --ping --host=machineX --port=4141</pre>
</div>
</li>
</ul>
</div>
<div  id="client-python-interface">
<h2>Client Python Interface<a  href="#client-python-interface" title="Permalink to this headline">¶</a></h2>
<div >
<div >The functionality provided by <a  href="/wiki/display/ECFLOW/Glossary#term-ecflow-client"><em >ecflow_client</em></a> is also available via the <a  href="/wiki/display/ECFLOW/ecFlow+Python+Api#python-api"><em>ecFlow Python Api</em></a>.</div>
<div >Please see <tt ><span >ecflow.Client</span></tt>.</div>
</div>
<div >
<div >The python interface uses the same algorithm for determining the host and port,</div>
<div >and allows the host and port to be set explicitly. See class <tt ><span >ecflow.Client</span></tt></div>
<div >This is shown by the following python example:</div>
</div>
<div ><div ><pre><span >import</span> <span >ecflow</span>

<span >ci</span> <span >=</span> <span >ecflow</span><span >.</span><span >Client</span><span >()</span>
<span >ci</span><span >.</span><span >set_host_port</span><span >(</span><span >&quot;oetzi&quot;</span><span >,</span><span >&quot;3444&quot;</span><span >)</span>  <span ># Explicitly set host and port</span>
<span >try</span><span >:</span>
   <span >ci</span><span >.</span><span >ping</span><span >()</span>
<span >except</span> <span >RuntimeError</span><span >,</span> <span >e</span><span >:</span>
   <span >print</span> <span >&quot;failed: &quot;</span> <span >+</span> <span >str</span><span >(</span><span >e</span><span >);</span>
</pre></div>
</div>
<p>What to do:</p>
<div >
<div >If your <a  href="/wiki/display/ECFLOW/Glossary#term-ecflow-server"><em >ecflow_server</em></a> was started with <strong>ecf_start.sh</strong> and wish to use the shell</div>
<div >interface, then set ECF_NODE and ECF_PORT environment variables</div>
</div>
</div>
</div>