Interesting..

Where does the 8 second limit come from? (Rodeos and bull/bronc riding, where 
you only have to stay on for 8 seconds?) I’ve seen this 8 second thing in a 
bunch of places lately, and I wonder.. why not 7, or 10 or whatever?  I find it 
hard to believe that someone has a 3 bit counter in seconds (or worse, it’s a 
33 bit counter counting nanoseconds or some such, and the limit is actually 
8.589 seconds)

From: Beowulf <beowulf-boun...@beowulf.org> on behalf of John Hearns 
<hear...@gmail.com>
Date: Wednesday, November 25, 2020 at 2:42 AM
To: Tim Cutts <t...@sanger.ac.uk>
Cc: "beowulf@beowulf.org" <beowulf@beowulf.org>
Subject: [EXTERNAL] Re: [Beowulf] Lambda and Alexa [EXT]

Aha. I did not know about the 8 second limit. I use Alexa with a Philips smart 
lighting hub to control house lights. Sometimes nothing happens...
I assumed this was Alexa not understanding a Scottish accent. I forgive Alexa 
now - she might have been having trouble talking to the Hue.

On Wed, 25 Nov 2020 at 10:21, Tim Cutts 
<t...@sanger.ac.uk<mailto:t...@sanger.ac.uk>> wrote:
Indeed, my main personal experience with Lambda so far has been in writing an 
Alexa skill in my spare time.  It’s been quite fun, and very instructive in the 
benefits and pitfalls of lambda.

My main takehomes so far:

1.  I love the fact that there’s basically no code at all other than that 
required to deliver the actual skill. Just handler functions for the incoming 
requests (Intents, as Amazon call them)

2.  Debugging is awkward.  There is no interactive debugging, as far as I can 
tell.   Log inspection is about all you have, and some errors are obtuse (for 
example, some valid Node.js constructs produce syntax errors on Lambda, and 
it’s very hard to track down when it happens - unit tests all pass locally but 
then you get a syntax error in the LogWatch logs, with a useless stack trace 
that doesn’t tell you where the syntax error is).  Debugging and unit testing 
on your laptop is hard to do; many Alexa APIs rely on real hardware functions 
and the simulators don’t handle them.

3.  Persistence of data is fairly straightforward using S3 buckets or DynamoDB, 
and I haven’t noticed latency issues with those (of course the interactions are 
on a human timescale, so latency isn’t really much of an issue)

4.  Interaction with external services can be problematic; Alexa lambda 
functions must return within 8 seconds, which can be fun if your skill needs to 
fetch data from some other source (in my case a rather sluggish data service in 
Azure run by my local council), and there’s no clean way to handle the event if 
you hit the 8 second limit, the function just gets terminated and Alexa returns 
a rather meaningless error to the user.

Tim

On 25 Nov 2020, at 09:45, John Hearns 
<hear...@gmail.com<mailto:hear...@gmail.com>> wrote:

BTW, I am sure everyone knows this but if you have a home assistant such as 
Alexa everytime you ask Alexa it is a lambda which is spun up


-- The Wellcome Sanger Institute is operated by Genome Research Limited, a 
charity registered in England with number 1021457 and a company registered in 
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