Thursday, February 4, 2016

Your Errata Submission for ...


My phone screen flashed earlier this a.m. with the reception of e-mails indicating that a couple of fixes for typographical errors which I submitted some time ago for Fluent Python have been accepted by the author. I was motivated to submit them because of the near-perfection of the book, beautiful in concept and in implementation; it was my opportunity to help maintain a wonderful work. Just as importantly, the publisher made it easy.

The contribution of a quotation mark and a two-letter English word to a 740-page book is hardly remarkable. It is instead what is now an ordinary task made easy by the Internet — the same Internet that contributed immensely to the creation of the book in the first place, from the development and popularity of the subject matter of the book to the tools which were used to create it to the ability of a publisher to interact with more authors to the electronic marketing and commerce which resulted in my purchase.

This is not unlike the creation of the software we all use daily. A large amount of it has the mark of a company but it relies to a tremendous extent on open source software, easily obtained, usually easy to contribute to, and truly ubiquitous even in so-called proprietary software with which we interact. It works because of countless contributions big and small from developers all over the world, using collaboration methods made easy by the Internet. Ease of collaboration enables contributions which have further eased collaboration (not to mention the rest of electronic life), and the software industry is built on the result.

It is time to close the door on what has been called open source strategy, as the use of open source software and the need for strategies for appropriate consumption of the software and interaction with the communities has invaded even the darkest corridors of proprietary software development and become business as usual. All software projects are a fusion of open source and custom-built components, whether or not everyone involved acknowledges it.

I look forward to a refresh of my electronic copy of Fluent Python with the latest corrections. But since submitting those fixes to the book text, I've collaborated with a handful of open source projects in the Django ecosystem for the first time and seen most of my small contributions there accepted; I am still watching some of those for feedback from the project maintainer or for inclusion in a new release. Those contributions were an important day-job activity, enabling features that our customer requested which didn't quite fit into the existing application.

Possible upcoming book contribution — convince the Two Scoops of Django authors to rework their claim that you can't pass environment variables to Django apps running with Apache httpd :) I'm sure they think that Apache+Django implies mod_wsgi, and I guess it is not fun to pass through OS-level environment variables in that configuration. My 2 cents on that matter: Deploying Python Applications with httpd (PDF)

Monday, October 5, 2015

cmake Windows nghttp2


This is just a web-search-findable note that I have an initial implementation of nghttp2 cmake-based build support for Windows (just the core library), at https://github.com/trawick/nghttp2-minimal-cmake. See the note on future plans for issues I hope to resolve soon before I submit it to the nghttp2 project.

Tuesday, August 11, 2015

Tuesday, January 27, 2015

Today's Python homework


The card I gave myself today says "Read Python language docs until I have written down 10 new things." Why? Somebody pointed out that var = val or '-' was cleaner than the mess I used instead, and I realized that much more effort is required. (Were it Perl, I'd probably have used or '-', but I can't always keep the features of the different languages straight.)

Here's today's list, which includes some things I'm familiar with in Python or other languages but can't pull out of a hat on demand.

  1. The file is UTF-8: # -*- coding: utf-8 -*- (or UTF-8 byte-order mark or VIM-style coding string)
  2. Identifiers named _* are not imported by from module import *. (I knew that a leading _ is for privacy but I didn't realize it was enforced anywhere besides analysis tools. But I don't think I use from module import * except with cascaded Django settings.)
  3. Identifiers named __* are class-private, and this is essentially enforced.
  4. Wow, combining string prefixes, as in ur or br, is new to me, as is using upper case string prefixes, such as R, bR, etc.
  5. I forgot about escape sequences for Bell, Backspace, Formfeed, and Vertical Tab, and never knew about \N{name-of-Unicode-character}. (I probably didn't know about octal escape sequences in Python either.)
  6. I don't always use whitespace to concatenate string literals, though I should where applicable.
  7. complex literals — 3.14j, 3.14e-10j
  8. ^ operator, for XOR
  9. the NotImplemented single-valued type, for returning from certain methods
  10. the Ellipses single-valued type, for indicating the presence of the ... syntax in a slice

Saturday, August 2, 2014

Google App Engine: skipping complete directory via skip_files


I forgot all about the skip_files in app.yaml and asked my favorite search engine what to do. A number of the top pages returned made it unnecessarily complicated. Just do this to skip directories (.idea and tools in this example):

...
skip_files:
- ^(.*/)?#.*#$
- ^(.*/)?.*~$
- ^(.*/)?.*\.py[co]$
- ^(.*/)?.*/RCS/.*$
- ^(.*/)?\..*$
- ^\.idea$
- ^tools$
...

(These are top-level directories within my app engine project.)

Add -v to your appcfg.py ... update ... invocation to confirm, from messages like

2014-08-02 09:19:20,424 INFO appcfg.py:2568 Ignoring directory '.idea': Directory matches ignore regex. 
2014-08-02 09:19:20,425 INFO appcfg.py:2426 Processing file 'app.yaml' 
2014-08-02 09:19:20,426 INFO appcfg.py:2426 Processing file 'index.yaml' 
2014-08-02 09:19:20,426 INFO appcfg.py:2426 Processing file 'main.py' 
2014-08-02 09:19:20,426 INFO appcfg.py:2561 Ignoring file 'main.pyc': File matches ignore regex. 
2014-08-02 09:19:20,426 INFO appcfg.py:2426 Processing file 'not_found.py' 
2014-08-02 09:19:20,427 INFO appcfg.py:2568 Ignoring directory 'tools': Directory matches ignore regex. 
2014-08-02 09:19:20,429 INFO appcfg.py:2426 Processing file 'static/Chart.min.js' 
...

Friday, August 1, 2014

Another year (or two), another release of mod_whatkilledus and mod_backtrace


mod_whatkilledus and mod_backtrace V2.01

I have a sinking feeling that this isn't pertinent to a fairly large percentage of the world's inhabitants, but it was a fair amount of hours spread over time and it's finally done, so I'll pretend otherwise.

mod_whatkilledus improvements

  • The name of the log file can now be configured with the WKULogfile directive.
  • On Windows: Add directive WKUDisableWindowsErrorBox to allow disabling the pop-up error handling dialog after a child process crash.
  • On Windows: Handle exceptions in 64-bit builds.
  • With Event MPM on Unix: When building with httpd 2.4.10 or later, properly track request processing across threads with the Event MPM. Previously, the wrong client and/or request might be logged as the trigger for a crash (with the Event MPM only). The change is not effective when building with httpd 2.4.9 or earlier.

mod_backtrace improvements

  • Support libunwind on Linux, FreeBSD, and OS X. This provides better resolution of function names, so a raw address will be provided in lieu of the function name in fewer situations. (Add LIBUNWIND=yes to the make invocation.) OS X note: A libunwind build silently fails to capture a backtrace with 32-bit builds, so use the default mechanism with 32-bit builds on OS X.
  • Filter out internal functions from backtraces so that only the caller's stack frames are reported.
  • Improve formatting of a backtrace for the error log field.

Windows binaries

64-bit binaries are now included for use with httpd 2.2 and 2.4 on Windows. (32-bit binaries are still included.)

Build improvements

  • Support make APXS=/path/to/apxs for building with non-default install layouts.
  • Support Clang on FreeBSD 10.
  • Add -funwind-tables on ARM platform for better backtraces.
  • mod_whatkilledus fails to build in a less mysterious way when using an httpd build that doesn't have exception hooks enabled.