Following some discussions at work and the will of the team to adopt a python code formatter, I set out to explore some of them. No need to say, the contenders had to aim towards pep8 compliance. Here are my findings on three of them.
Continue reading “Python code formatters comparison: Black, autopep8 and YAPF”
Category: IT
Information Technology
bookmark_borderAWS marketplace and no longer supported instance types
I’ve been trying and trying to launch a Neo4j instance on the marketplace without success. It always gave me the nice “success” message, but when I went to the EC2 console: nothing!
I finally decided to do it the hard way: manually. First step: select an instance type. I immediately try to select the same low cost instance I had picked in the marketplace (m3.medium) and to my surprise that type wasn’t there.
Adding 1 + 1, I went back to the market place and tried with an instance type that still exists: m4.large… success!
So I don’t know who is to blame here, but here are my 2 questions to the internet:
- Why do we get the success message even though it doesn’t work?
- Why are unsupported instance types offered in the market place?
bookmark_borderPython logging to stackdriver
I recently deployed a python application in google app engine / container engine. When I went to check the logs, everything was logged at the “ERROR” level even though my application uses python logging properly. As far as I know there are 2 ways to fix that:
- Use the stackdriver client, which requires an additional dependency and somewhat binds your program to google app engine.
- Format the logs in a way that stackdriver can parse them, which is easily configurable.
bookmark_borderRecipe: Testing multiple python versions with pyenv and tox
If you develop a ton of python applications and you need to test under a lot of different versions, and by a lot I mean overlapping major/minor versions (like 3.5.3 and 3.5.4), then a good option is to use pyenv. Along with tox, you can easily test your application against various major/minor versions.
Here is how to do it.
Continue reading “Recipe: Testing multiple python versions with pyenv and tox”
bookmark_borderRecipe: Google App Engine, Cloud SQL and sqlalchemy
Here is a recipe on how I made those thing work together both on a linux development environment and in production. The important thing to remember is: just like recipes for brownies, there are other recipes to achieve the same thing.
The following steps assume you have a Google cloud account with the proper permissions.
Continue reading “Recipe: Google App Engine, Cloud SQL and sqlalchemy”
bookmark_borderFixing Windows 10 sound issue/noise
For a few months I have been struggling with small sound issues. It’s hard to put words to describe it, but it was like noise/static here and there, more often than not while playing games and rendering 3D.
I tried reinstalling audio drivers but that didn’t fix the issue. Finally, I found a post (to which I lost the link) with the solution.
In Windows 10 power options, I changed the configuration from “balanced” to “performance”.
bookmark_borderSGE/OGS: Clean your logs
At Datacratic, part of our infrastructure runs in the cloud. Our elastic cluster is managed by StarCluster and job dispatch is managed by Open Grid Scheduler (OGS), a fork of Sun Grid Engine (SGE).
While I was looking at StarCluster’s output to help a new user, I realized there was a lot of timeouts. I dug a bit and found out that the command qacct was too slow. Following the lead, I understood that the said command parses a text file each time it is executed.
After a few years of operations, our main cluster has dispatched over 5 000 000 jobs. The log file parsed by qacct was about 2Gb in size. Tada! A couple of search queries taught me that OGS, in its install directory (<path to ogs>/util/logchecker.sh), has a script, ready to be configured, to rotate its logs. I configured and launched it. The timeouts are gone.
Lesson learned: StarCluster/OGS operators, it is important to configure and schedule that script to run every now and then if you want to keep your operations stable.
bookmark_borderC++ / Python Wrapping and system_signal_exception
While working on a C++ program that made use of a Python wrapped library to start a subprocess, when the subprocess crashed I got a boost::detail::system_signal_exception at the C++ level even though the executing context was still on the python layer. How is that possible?
Continue reading “C++ / Python Wrapping and system_signal_exception”
bookmark_borderPython sys.exit: a suggestion
I was surprised this morning when I realized that the call to sys.exit is not really exiting. It is instead raising exception SystemExit which, if left unhandled, will exit with the proper exit code.
Continue reading “Python sys.exit: a suggestion”
bookmark_borderStarCluster: Multiple node instance type support
Last week I released a new feature for the vanilla_improvements branch of StarCluster: multiple instance type support. It means that our cluster can now select the instance type to bid on depending on a configurable factor and the lowest spot market price for each type.
Want to see how it works? Head to the wiki. Want to know more about how I did it? Read further.
Continue reading “StarCluster: Multiple node instance type support”