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<div>I'm still stewing on this but at first blush this seems like an artificial abstraction. What do we really gain from having another layer above the service api's? Can't they just live at the service api?</div>
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<div>For example:</div>
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<div>nova.compute.api:create_instance()</div>
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<div>vs. </div>
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<div>nova.business_layer:create_instance()</div>
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<div id="divRpF624151" style="direction: ltr; "><font face="Tahoma" size="2" color="#000000"><b>From:</b> Lorin Hochstein [lorin@isi.edu]<br>
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<div>I think it actually looks more like this right now: </div>
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<div><span class="Apple-style-span" style="font-family:'Courier New'">EC2 Client OS Client</span></div>
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<div><font class="Apple-style-span" face="'Courier New'"> | |</font></div>
<div><font class="Apple-style-span" face="'Courier New'">EC2 API OS API</font></div>
<div><font class="Apple-style-span" face="'Courier New'"> \ /</font></div>
<div><font class="Apple-style-span" face="'Courier New'"> [nova-*] service APIs</font></div>
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<div>There isn't really a single back-end API for the front-end APIs to call into. Instead, each of them makes calls to the multiple service APIs (e.g., scheduler, network, compute). </div>
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<div>I would advocate for something more like this:</div>
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<div><span class="Apple-style-span" style="font-family:'Courier New'">EC2 Client OS Client</span></div>
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<div><font class="Apple-style-span" face="'Courier New'"> | |</font></div>
<div><font class="Apple-style-span" face="'Courier New'">EC2 API OS API</font></div>
<div><font class="Apple-style-span" face="'Courier New'"> \ /</font></div>
<div><font class="Apple-style-span" face="'Courier New'"> internal nova API</font></div>
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<div><font class="Apple-style-span" face="'Courier New'"> |</font></div>
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<div><font class="Apple-style-span" face="'Courier New'"> [nova-*] service APIs</font></div>
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<div style="font-family:Helvetica">This is a single, unified API that is meant only for internal use. This would reduce the coupling between front-end and back-end. It would make it easier for someone with less expertise in the code (hello!) to find the location
in the code that answers questions like: "What does nova do when a user requests that an instance is launched?" They would just look at the internal API and find the appropriate method. It would also make it easier to add additional front-ends, if there's
ever any interest in that.</div>
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