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2017/08/02

Considering Code Documentation

I was procrastinating about a work project, thinking about magnets, thinking about crushers, thinking about thermite, when I thought about my status tracker.

It goes by the name status.pl because status is already a DBus utility. I made some other decisions relating to command-line interface, moving away from a cool idea I had a few years ago that hasn't aged well. I changed it to record.pl, which isn't similarly overloaded on my system, at least, and wrote a few flags for it, mostly for overkill. I mean, at core, it's because Len Budney convinced me my scripts needed manners, especially it not doing anything when just called.

So, I wrote this. All the details are tucked in Status.pm, which I am not sharing and which needs an overhaul too. All in all, I am reasonably happy with this; If there was a useless use of sub signatures award, I think this'd be a contender, but both that and postderef are used in get_records.pl,  so it's okay. (I put no warnings because I'm running 5.26 on my desktop, but it is likely that I'll copy this to cluster machines running our 5.20 or the system 5.10 Perls, which would need the warnings.) I could and probably should go without IO::Interactive, but still.

So, my question is, beyond the user documentation that gets passed through Pod::Usage, what documentation does this program need? I'm always at a loss for examples of what is needed. In general, programmers discount documentation; most editor themes I see make comments gray and muted, which has always angered me, but looking at this (and yes, it's a slight case) I'm at a loss to decide what would be important to add.

So, what comments would you add? What do you find wanting?

(If desired, to add to this conversation, I can add the display section and the module.)

2017/07/26

Using VS Code and Ligatures

Quick history: I started out as a vi man, having the comical "how do I save and exit?" issues with emacs that I see lots of people complain about for vim. After college, my first job's standard editor was UltraEdit. In the lab, I experimented with KomodoEdit, have been a Sublime Text 2 user, and right now, on both Windows and Linux, I'm using Visual Studio Code.

As well as vim. There are occasional things VS Code can't do, or at least can't do with the packages I know about. Line sorting, for one. I like to have my modules sorted; it helps me to see if the one I want is called.

Similarly, over time, I have developed a fondness for specific fonts in my editor. I cannot go through a long history of preference, but I can say that variations of Droid Sans Mono with modifications for a dotted or slashed zero do more easily distinguish them from capital O are normally what I run in terminals and editors.

But, I recently saw Scott Hanselman blog on Monospace Programming Fonts with Ligatures.

What's that?

Consider the code from yesterday's post on Sentiment Analysis. There are a couple places where there are skinny arrows (->), fat arrows (=>) and greater-than-and-equal signs (>=). Look specifically at line 21 for skinny arrows and greater-and-equal. Pretty, isn't it? I will also point out that line 21 also shows the dotted 0 and how easy it is to distinguish it from letters.

Also look at the logical AND (&&) on like 36.


These are just in-the-editor changes; the code from yesterday's post is copied from this editor.

The font I'm using is called Fira Code, and it's on GitHub. There are others, like Monoid and Hasklig that can do this, but I like Fira Code. Within VS Code, you also have to add "editor.fontLigatures": true to your settings.

I have it as my font for the HexChat IRC client, which supports ligatures, and Git for Windows Bash, Windows Subsystem for Linux and PowerShell terms on Windows, which don't, but the font still looks good. I noticed an issue where it swallowed the equal sign in Gnome Terminal, so there I'm back to Droid Sans Mono Slashed, but that might have been a temporary issue.

Hrmm. Yesterday, I wrote on an Azure API. Today, I'm praising a Visual Studio-related editor. Tomorrow, I might get into the Windows Subsystem for Linux.

2017/07/25

Sentimentalizing Twitter: First Pass

It started here.

I couldn't leave it there.

I can write a tool that goes through all old tweets and deletes ones that don't pass criteria, but I prefer to get out ahead of the issue and leave the record as it is.

And, as a later pass, one can pull a corpus, use a module like Algorithm::NaiveBayes and make your own classifier, rather than using Microsoft Research's Text Analytics API or another service. I was somewhere along that process when the hosting died, so I'm not bringing it here.

I was kinda under the thrall of Building Maintainable Software, or at least the first few chapters of it, so I did a few things differently in order to get their functions less than 15 lines, but the send_tweet function didn't get the passes it'd need, and I could probably give check_status some love, or perhaps even roll it into something like WebService::Microsoft::TextAnalytics. In the mean time, this should allow you to always tweet on the bright side of life.

#!/usr/bin/env perl

use feature qw{ postderef say signatures } ;
use strict ;
use warnings ;
use utf8 ;

no warnings qw{ experimental::postderef experimental::signatures } ;

use Carp ;
use Getopt::Long ;
use IO::Interactive qw{ interactive } ;
use JSON ;
use LWP::UserAgent ;
use Net::Twitter ;
use YAML qw{ LoadFile } ;

my $options = options() ;
my $config  = config() ;

if ( check_status( $options->{ status }, $config ) >= 0.5 ) {
    send_tweet( $options, $config ) ;
    }
else { say qq{Blocked due to negative vibes, man.} }
exit ;

sub send_tweet ( $options, $config ) {
    my $twit = Net::Twitter->new(
        traits          => [ qw/API::RESTv1_1/ ],
        consumer_key    => $config->{ twitter }{ consumer_key },
        consumer_secret => $config->{ twitter }{ consumer_secret },
        ssl             => 1,
        ) ;
    my $tokens = $config->{ twitter }{ tokens }{ $options->{ username } } ;
    if (   $tokens->{ access_token }
        && $tokens->{ access_token_secret } ) {
        $twit->access_token( $tokens->{ access_token } ) ;
        $twit->access_token_secret( $tokens->{ access_token_secret } ) ;
        }
    if ( $twit->authorized ) {
        if ( $twit->update( $options->{ status } ) ) {
            say { interactive } $options->{ status } ;
            }
        else {
            say { interactive } 'FAILED TO TWEET' ;
            }
        }
    else {
        croak( "Not Authorized" ) ;
        }
    }

sub check_status ( $status, $config ) {
    my $j   = JSON->new->canonical->pretty ;
    my $key = $config->{ microsoft }{ text_analytics }{ key } ;
    my $id  = 'tweet_' . time ;
    my $object ;
    push @{ $object->{ documents } },
        {
        language => 'EN',
        text     => $status,
        id       => $id,
        } ;
    my $json    = $j->encode( $object ) ;
    my $api     = 'https://westus.api.cognitive.microsoft.com/text/analytics/v2.0/sentiment' ;
    my $agent   = LWP::UserAgent->new ;
    my $request = HTTP::Request->new( POST => $api ) ;
    $request->header( 'Ocp-Apim-Subscription-Key' => $key ) ;
    $request->content( $json ) ;
    my $response = $agent->request( $request ) ;

    if ( $response->is_success ) {
        my $out = decode_json $response->content ;
        my $doc = $out->{ documents }[ 0 ] ;
        return $doc->{ score } ;
        }
    else {
        croak( $response->status_line ) ;
        }
    return 1 ;
    }

sub config () {
    my $config ;
    $config->{ twitter }   = LoadFile( join '/', $ENV{ HOME }, '.twitter.cnf' ) ;
    $config->{ microsoft } = LoadFile( join '/', $ENV{ HOME }, '.microsoft.yml' ) ;
    return $config ;
    }

sub options () {
    my $options ;
    GetOptions(
        'help'       => \$options->{ help },
        'username=s' => \$options->{ username },
        'status=s'   => \$options->{ status },
        ) ;
    show_usage( $options ) ;
    return $options ;
    }

sub show_usage ($options) {
    if (   $options->{ help }
        || !$options->{ username }
        || !$options->{ status } ) {
        say { interactive } <<'HELP';
Only Positive Tweets -- Does text analysis of content before tweeting

    -u  user        Twitter screen name (required)
    -s  status      Status to be tweeted (required)
    -h  help        This screen
HELP
        exit ;
        }
    }
__DATA__

.microsoft.yml looks like this
---
text_analytics:
    key: GENERATED_BY_MICROSOFT

.twitter.cnf looks like this

---
consumer_key: GO_TO_DEV.TWITTER.COM
consumer_secret: GO_TO_DEV.TWITTER.COM
tokens:
    your_username:
        access_token: TIED_TO_YOU_AS_USER_NOT_DEV
        access_token_secret:TIED_TO_YOU_AS_USER_NOT_DEV

I cover access_tokens in https://varlogrant.blogspot.com/2016/07/nettwitter-cookbook-how-to-tweet.html


2017/07/22

The Next Thing

As discussed last time, I had been using my GitHub Pages space as a list to my Repos. I had been considering moving my blogging from here to ... something else, and this looked like an interesting concept.

I've always developed the web with a smart server side, and I've known from the start that this makes you very vulnerable, so I do like the idea of writing markdown, committing it to the repo and having the system take care of it from there. So, that's a win.

But, as far as I can tell, I've followed the "this is how you make an Atom feed" magic and get no magic from it, and that, more than webhooks triggering on push, is how you start putting together the social media hooks that make blogging more than writing things down in a notebook. Which is a lose.

So, I'm not 100% happy with GitHub Pages and Jekyll, but the good thing is that I can write and commit from anywhere. If I used Statocles or another static site generator, I'd have to have that system running on whatever computer I blog from, or transfer it to there.

I would guess that, if I had the whole deal running on any of my machines, some of the small things would work better, but so far, getting a setup that displays pages exactly like github.io on localhost has been less that working, And, I would've like to have this as a project page, jacoby.github.io/blog, so my personal page could be more of a landing page, but alas.

And, ultimately, I do want to not have myblog.<service>.com, but rather myblog.<me>.com. Every time I think about it, I think about the tools I'd build on it, rather than the billboard for me, but

2017/07/13

Github to Perl to Github? Putting your projects on a web page

My projects are on GitHub: https://github.com/jacoby/

I have a page on GitHub: https://jacoby.github.io/

Early in my playing with Bootstrap, I made this as a way to begin to play with it. It is about as simple a GitHub API to LWP to Template Toolkit to Bootstrap tool as I could have written. I'm now thinking about how to make this prettier, but for now, it's what I use to generate, when I remember to redo my GitHub page. Learn and enjoy.

2017/07/07

Temperature based on Current Location for the Mobile Computer


I'm always curious about how people customize their prompt. I put name and machine in, with color-coding based on which machine, because while spend most of my time on one or two hosts, I have reason to go to several others.

I work in a sub-basement, and for most of my work days, I couldn't tell you if it was summer and warm, winter and frozen, or spring and waterlogged outside, so one of the things I learned to check out is current weather information. I used to put the temperature on the front panel of our HP printer, but we've moved to Xerox.

Currently, I use DarkSky, formerly forecast.io. I know my meteorologist friends would recommend more primary sources, but I've always found it easy to work with.

I had this code talking to Redis, but I decided that it was an excuse to use Redis and this data was better suited for storing in YAML, so I rewrote it.

store_temp
#!/usr/bin/env perl

# stores current temperature with YAML so that get_temp.pl can be used
# in the bash prompt to display current temperature

use feature qw{ say state } ;
use strict ;
use warnings ;

use Carp ;
use Data::Dumper ;
use DateTime ;

use IO::Interactive qw{ interactive } ;
use JSON ;
use LWP::UserAgent ;
use YAML::XS qw{ DumpFile LoadFile } ;

my $config = config() ;
my $url
    = 'https://api.darksky.net/forecast/'
    . $config->{apikey} . '/'
    . ( join ',', map { $config->{$_} } qw{ latitude longitude } ) ;
my $agent = LWP::UserAgent->new( ssl_opts => { verify_hostname => 0 } ) ;
my $response = $agent->get($url) ;

if ( $response->is_success ) {
    my $now = DateTime->now()->set_time_zone('America/New_York')->datetime() ;
    my $content  = $response->content ;
    my $forecast = decode_json $content ;
    my $current  = $forecast->{currently} ;
    my $temp_f   = int $current->{temperature} ;
    store( $now, $temp_f ) ;
    }
else {
    say $response->status_line ;
    }

exit ;

# ======================================================================
sub store { my ( $time, $temp ) = @_ ; say {interactive} qq{Current Time: $time} ; say {interactive} qq{Current Temperature: $temp} ; my $data_file = $ENV{HOME} . '/.temp.yaml' ; my $obj = { curr_time => $time, curr_temp => $temp, } ; DumpFile( $data_file, $obj ) ; } # ====================================================================== # Reads configuration data from YAML file. Dies if no valid config file # if no other value is given, it will choose current # # Shows I need to put this into a module sub config { my $config_file = $ENV{HOME} . '/.forecast.yaml' ; my $output = {} ; if ( defined $config_file && -f $config_file ) { my $output = LoadFile($config_file) ; $output->{current} = 1 ; return $output ; } croak('No Config File') ; }

And this is the code that reads the YAML and prints it, nice and short and ready to be called in PS1.

get_temp
#!/usr/bin/env perl

# retrieves the current temperature from YAML to be used in the bash prompt

use feature qw{ say state unicode_eval unicode_strings } ;
use strict ;
use warnings ;
use utf8 ;
binmode STDOUT, ':utf8' ;

use Carp ;
use Data::Dumper ;
use YAML::XS qw{ LoadFile } ;

my $data_file = $ENV{HOME} . '/.temp.yaml' ;
my $output    = {} ;
if ( defined $data_file && -f $data_file ) {
    my $output = LoadFile($data_file) ;
    print $output->{curr_temp} . '°F' || '' ;
    exit ;
    }
croak('No Temperature File') ;

I thought I put a date-diff in there. I wanted to be able say 'Old Data' if the update time was too long ago. I should change that.

I should really put the config files in __DATA__ for show, because it will show that the location is hard-coded. For a desktop or server, that makes sense; it can only go as far as the power plug stretches. But, for other reasons, I adapted my bash prompt on my Linux laptop, and I recently took it to another state, so I'm thinking more and more that I need to add a step, to look up where I am before I check the temperature.

store_geo_temp
#!/usr/bin/env perl

# Determines current location based on IP address using Google
# Geolocation, finds current temperature via the DarkSky API
# and stores it into a YAML file, so that get_temp.pl can be
# in the bash prompt to display current local temperature.

use feature qw{ say state } ;
use strict ;
use warnings ;
use utf8 ;

use Carp ;
use Data::Dumper ;
use DateTime ;
use IO::Interactive qw{ interactive } ;
use JSON::XS ;
use YAML::XS qw{ DumpFile LoadFile } ;

use lib $ENV{HOME} . '/lib' ;
use GoogleGeo ;

my $json     = JSON::XS->new->pretty->canonical ;
my $config   = config() ;
my $location = geolocate( $config->{geolocate} ) ;
croak 'No Location Data' unless $location->{lat} ;

my $forecast = get_forecast( $config, $location ) ;
croak 'No Location Data' unless $forecast->{currently} ;

say {interactive} $json->encode($location) ;
say {interactive} $json->encode($forecast) ;

my $now     = DateTime->now()->set_time_zone('America/New_York')->datetime() ;
my $current = $forecast->{currently} ;
my $temp_f  = int $current->{temperature} ;
store( $now, $temp_f ) ;

exit ;

# ======================================================================
# Reads configuration data from YAML files. Dies if no valid config files
sub config {
    my $geofile = $ENV{HOME} . '/.googlegeo.yaml' ;
    croak 'no Geolocation config' unless -f $geofile ;
    my $keys = LoadFile($geofile) ;

    my $forecastfile = $ENV{HOME} . '/.forecast.yaml' ;
    croak 'no forecast config' unless -f $forecastfile ;
    my $fkeys = LoadFile($forecastfile) ;
    $keys->{forecast} = $fkeys->{apikey} ;
    croak 'No forecast key' unless $keys->{forecast} ;
    croak 'No forecast key' unless $keys->{geolocate} ;
    return $keys ;
    }

# ======================================================================
# Takes the config for the API keys and the location, giving us lat and lng
# returns the forecast object or an empty hash if failing
sub get_forecast {
    my ( $config, $location ) = @_ ;
    my $url
        = 'https://api.darksky.net/forecast/'
        . $config->{forecast} . '/'
        . ( join ',', map { $location->{$_} } qw{ lat lng } ) ;
    my $agent = LWP::UserAgent->new( ssl_opts => { verify_hostname => 0 } ) ;
    my $response = $agent->get($url) ;

    if ( $response->is_success ) {
        my $content  = $response->content ;
        my $forecast = decode_json $content ;
        return $forecast ;
        }
    return {} ;
    }

# ======================================================================
sub store { my ( $time, $temp ) = @_ ; say {interactive} qq{Current Time: $time} ; say {interactive} qq{Current Temperature: $temp} ; my $data_file = $ENV{HOME} . '/.temp.yaml' ; my $obj = { curr_time => $time, curr_temp => $temp, } ; DumpFile( $data_file, $obj ) ; }

A few things I want to point out here. First off, you could write this with Getopt::Long and explicit quiet and verbose flags, but Perl and IO::Interactive allow me to make this context-specific and implicit. If I run it myself, interactively, I am trying to diagnose issues, and that's when say {interactive} works. If I run it in crontab, then it runs silently, and I don't get an inbox filled with false negatives from crontab. This corresponds to my personal preferences; If I was to release this to CPAN, I would likely make these things controlled by flags, and perhaps allow latitude, longitude and perhaps API keys to be put in that way.

But, of course, you should not get in the habit, because then your keys show up in the process table. It's okay if you're the only user, but not best practice.

This is the part that's interesting. I need to make it better/strong/faster/cooler before I put it on CPAN, maybe something like Google::Geolocation or the like. Will have to read some existing Google-pointing modules on MetaCPAN before committing. Geo::Google looks promising, but it doesn't do much with "Where am I now?" work, which is exactly what I need here.

Google's Geolocation API works better when you can point to access points and cell towers, but that's diving deeper than I need; the weather will be more-or-less the same across the widest accuracy variation I could expect.

GoogleGeo
package GoogleGeo ;

# interfaces with Google Geolcation API 

# https://developers.google.com/maps/documentation/geolocation/intro

use feature qw{say} ;
use strict ;
use warnings ;

use Carp ;
use Data::Dumper ;
use Exporter qw(import) ;
use Getopt::Long ;
use JSON::XS ;
use LWP::Protocol::https ;
use LWP::UserAgent ;

our @EXPORT = qw{
    geocode
    geolocate
    } ;

my $json  = JSON::XS->new->pretty ;
my $agent = LWP::UserAgent->new ;

sub geocode {
    my ($Google_API_key,$obj) = @_ ;
    croak unless defined $Google_API_key ;
    my $url = 'https://maps.googleapis.com/maps/api/geocode/json?key='
        . $Google_API_key ;
    my $latlng = join ',', $obj->{lat}, $obj->{lng} ;
    $url .= '&latlng=' . $latlng ;
    my $object = { latlng => $latlng } ;
    my $r = $agent->post($url) ;
    if ( $r->is_success ) {
        my $j = $r->content ;
        my $o = $json->decode($j) ;
        return $o ;
        }
    return {} ;
    }

sub geolocate {
    my ($Google_API_key) = @_ ;
    my $url = 'https://www.googleapis.com/geolocation/v1/geolocate?key='
        . $Google_API_key ;
    my $object = {} ;
    my $r = $agent->post( $url, $object ) ;
    if ( $r->is_success ) {
        my $j = $r->content ;
        my $o = $json->decode($j) ;
        return {
            lat => $o->{location}{lat},
            lng => $o->{location}{lng},
            acc => $o->{accuracy},
            } ;
        }
    return {} ;
    }

'here' ;

If this has been helpful or interesting to you, please tell me so in the comments.

2017/07/06

Working Through Limitations: The Perl Conference 2017 Day 3

A Delorean with a Perl-powered center column and the cutest little Flux Capacitor on the dashboard. Oh, the wonders you can see at a developer conference.
"A man's got to know his limitations."

That's a line from Dirty Harry Callahan in Magnum Force, but it really described my planning for the Perl Conference. Once the calendar was up, I went in, first and foremost thinking "What are skills I need to learn?"

One crucial skill is version control. It's difficult to add to my main workflow, as I develop in production. (I live in fear.) But I'm increasingly adding it to my side projects. It is especially part of the process for maintaining the site for Purdue Perl Mongers, as well as aspects of HackLafayette, but beyond certain basics, I just didn't know much about how to use Git and version control to improve my projects. I learned how CPAN Testers tests your code on many platforms after you upload to CPAN, and how Travis-CL and Appveyor test against Linux, macOS and Windows after pushing to GitHub, but how track changes, align issues with branches, etc., are all new to me. So, I started Wednesday with Genehack and Logs Are Magic: Why Git Workflows and Commit Structure Should Matter To You. (Slides) I fully expect to crib ideas and aliases from this talk for some time to come.



There was a talk at a local software group featuring a project leader from Amazon on the technology involved with Alexa, which involved a lot of how this works, going from speech-to-text to tokenization and identifying of crucial keywords -- "Alexa, have Domino's order me a Pizza" ultimately boiling down to "Domino's" and "Pizza" -- and proceeding from there. It gave a sense of how Amazon is taking several hard problems and turning them into consumer tools.

What came very late in the talk is how to interface my systems with Amazon's "Talking Donkey", and I had a few conversations where we talked about starting the day with "Alexa, what's fresh hell is this?" and getting back a list of systems that broke overnight, but I lacked a strong idea of what is needed to make my systems interact with the Alexa system.

And an Echo.

But, thankfully, Jason Terry's Amazon, Alexa and Perl talk covered this, albeit more in the "Turn my smart lights on" sense than in the "Tell me what my work systems are doing" sense. Still, very much something I had been interested in.



But, as I implied, Amazon does a lot of heavy lifting with Alexa, getting it down to GETs and and POSTs against your API. If you're running this from home, where you have a consistent wired connection, this works. But, if you're running this, for example, in your car, you need it to be small, easy, and self-contained. Chris Prather decided to MAKE New Friends with a Raspberry Pi 3. This was a case of Conference-Driven Development, and he didn't have it ready to demonstrate at this time.



I've been trying to move my lab to the New Hotness over time, and because I will have to tie things back to existing systems, I have avoided learning too much in order to make it work. Joel Berger presented Vue.js, Mojolicious, and PostgreSQL chat in less than 50 lines. I've heard good things about Vue.js, which I heard from the project head was the parts he needed from Angular without the stuff he didn't use. (RFC Podcast) I use jQuery and Template and not much more, so the "only what you need" aspect sounds good to me. I fully expect to bug Joel on Twitter and IRC about this and other things I need to do with Mojolicious  over the coming months. (Slides)



But, of course, not every talk needs to speak directly to my short-term needs. Stevan Little has been trying to add an object system to the Perl 5 for quite some time, and in Hold My Beer and Watch This, he talks about Moxie, his latest attempt.



OK, the Moxie talk was in the same room as the Mojolicious talk and this next one. I could have gone to one of the others, but I decided against. Oh well. I would put "do more object-oriented development" as a thing to learn, so I was glad to hear it.

The last full talk was The Variable Crimes We Commit Against JavaScript by Julka Grodel. I would say that I code Javascript half as much as I code Perl, but twice as much as I code in other languages. I knew certain parts, like how let gives lexical scoping like Perl's my. I had heard about let from my JS Twitter list, as well as from Matt Trout's talk, but there were certainly things I didn't know.

And, actually, things I still don't. I had technical difficulties with my laptop, and if I could've worked it out that day, I would've tried to set up a lightning talk. Alas, not only did it not work -- in the end, I swapped out the WiFi, and I think if I switched back, it'd be sane again -- I missed a lot of her talk about arrow functions, which piqued the interest of Perl's functional programming guru, Mark Jason Dominus. (In a not-surprising addition to my limitations, I still haven't gotten to the end of Higher Order Perl.) Anyway, I believe that, after I finish this post, I will go back and watch this again.



After this, there were Lightning Talks, interspersed with ads for various Perl Mongers groups, and urges for you to start a Perl Mongers group. I am likely going to do another post, with these talks from all three days, but to end this one, I'll show off one where M. Allan Noah talks about the SANE Project and how he reverse engineers scanner output to allow him to support scanners without vendor input.



Lack of documentation is a limitation, but knowing the limitation does not mean you have to stop, and lack of documentation will not stop him. We should all draw inspiration from that.

Now that I'm two weeks past the end, most of the talks are up, and I would like to commend the organizers. Conference organization is hard, and this venue made it harder. The US Patent and Trademark Office is a great place, but there are aspects that they as a venue wanted secured and I would've preferred to be more open, but it was a beautiful venue and I be glad to return.

But, the thing I'd like to commend them most on is the high quality and fast turnaround on talk videos. The audio is good, the video is clear and well-lit, and the slides take precedence over the speaker in framing. It's everything I want in a conference video.

2017/06/29

Three Little Words: The Perl Conference 2017 Day 2

I lost the bubble.

I wrote a post at the end of the first day of the Perl Conference, intending to do the same for the second and third, but I went to visit family and play with their puppies on Tuesday night, and puppies are better than blogging.

Puppies!
The beginning of the third day, my laptop hit a weird issue where it couldn't enable the wireless NIC. I fixed it at home, once I had access to precision screwdrivers again, but this meant that I couldn't blog the last day, either.

But waiting affords me the opportunity to add videos of the talks I attended. So, yay.

I started Day 2 with Sam Batschelet's Dancing In The Cloud, which was not what I was expecting, being more a deep dive in another domain. I was hoping for an introduction to using the Dancer framework on cloud providers. It was interesting, and I now know what kubernetes does and that etcd exists, but this is far enough away from where I live that I don't know if it'll give me much more than buzzword recognition when I next attend a technical conference.


Again, I would like to reiterate that it was deep for me. Good talk, good speaker, but I was the wrong audience. Read the talk descriptions, not just the titles!

This was followed by Chad Granum on Test2, which is not yet on YouTube. I came to TPC wanting to up my testing game, and I've been looking through Andy Lester's modules and brian d foy's Stack Overflow posts trying to get into the mindset. This talk is a long-form walk through the diffs between the old and new test frameworks, and by showing how to test using Test2, it showed a lot about how to test in general. Once the talk is up, I am sure I will go through it again and again, trying to get my head around it.


But just because we don't have this talk on YouTube, that doesn't mean we don't have Chad talking about testing.

My next talk was Adventures in Failure: Error handling culture across languages by Andrew Grangaard, which is another point of growth for me. All too often, I just let errors fall, so knowing how they're commonly done is a good thing, well presented.


Damian Conway was the keynote speaker, and his talk was called Three Little Words. Those are, of course, I ❤ Perl.

Also, class has method. Conway proceeded to implement Perl6-style OOP with Dios, or Declarative Inside-Out Syntax, which needed Keyword::Declare to enable the creation of new keywords in Perl 5. To get this going, he needed to more quickly parse Perl, so along comes PPR, the Pattern-based Perl Recognizer. It was in this talk that the previous Lightning Talk from Chad, including his module Test2::Plugin::Source, comes from.

The Lightning Talks were good, but the one that comes up as a good one to put here is Len Budney's Manners for Perl Scripts. This makes me want to look into CLI::Startup.


I hope to get to Day 3 and maybe another post just on Lightning Talks soon. An hour's dive into topics won't get you too deep, but an hours' lightning talks will will open up a number of possibilities for you to follow.

2017/06/27

Reverse Engineering Google Maps at Highway Speed



I was on I-70 in Maryland on Sunday, going to Alexandria, Virginia, along with a lot of others. I was using Google Maps for navigation. When I could look down, the route was looking red, indicating congestion and delay. Eventually, Google said, "We have an alternate route that will save you a half hour. Want to take it?"

Of course I said yes. So I took the next exit, went down some rural highways, through a small town and almost down someone's driveway, it seemed, and back onto I-70. I called it a win.

The Friday after, on my way home, it rained all the way through Maryland, West Virginia, Pennsylvania and Ohio, and well into Indiana. It occasionally rained hard enough that I started seeing other drivers turning on their hazard lights for others to see them, and I followed suit.

A truck had crashed in western Ohio, closing westbound lanes, and Google told me it would add an hour delay, but when it routed me through five miles of county roads to the next on-ramp, it was closed. I knew it -- I saw the chain across the road -- but Google didn't, so I alone, without a line of other vehicles, bird-dogged a route to the next on-ramp with Google urging me to make a u-turn every few hundred feet.

This made me think about what's actually going on inside the navigation feature of Google Maps. It starts in graph theory, establishing the US road system as a directed graph with weighted edges, showing Interstates as preferable to highways to county roads and side streets, and using Dijykstra's shortest path algorithm to find the best route.

In graph theory, everything is either a node or an edge. In this case, a node could be the intersection of 6th and Main, or the fork where I-70 splits off to I-270.  The edges would be the road between 5th and 6th on Main St., or the long path between exits on the Interstate. In other uses of graph theory, the nodes are most important -- Facebook Users being nodes and their friendships being edges in Facebook's Social Graph -- but here, the information about the edges is the important part.

This is similar to how we used to do it, looking at a paper map and preferring Interstate for long-haul routes, judging this road or that road as preferable due to scenery or a hundred other criteria, dropping to surface streets only to get through the final few miles. But, Google knows this road gets gridlocked at rush hour and that one is under construction, which you can't tell from your ten-year-old road atlas, and has a huge body of historical data that allows it to present alternate routes and the estimated time difference between.

The increasing amount of data helps it properly weigh edges and make connections. Early in my time with Maps, it suggested I go from Lafayette to Ft Wayne through Indianapolis, which would actually add an hour to the trip, because it had weighted the Interstate so highly. Now, it properly suggests two east-west routes and avoids the southern detour entirely. Similarly, an intersection near work is right-turn only, and it took some time for Maps to not suggest a left turn.

Maps re-calculates the route often, which is why, after a time off its path, it still says "fastest way is behind you; turn around and go back". When you're just stopping for gas, it's a little annoying, but when you see that the highway department has blocked the suggested route, you wish it would just shut up and get with the program. I'd have to take more trips where I'm not the driver to really tell, but I would guess it re-runs shortest-path several times a minute. My guess is there are waypoints, places along the route between here and there, so Maps tries to find the shortest path between them, rather than rethinking every turn in your 600-mile journey, which makes this faster and more predictable.

Maps has a lot of data for each section of road, showing how many drivers use it and their average speed, as well as the posted speed limit. If the drivers are going slower than average and slower than the speed limit, that indicates there is a problem. In the Ohio case, the Department of Transportation must have reported that the reason was an accident, but to paraphrase Scream, causes are incidental. What's important is knowing where things get back to normal, and if cars aren't there, then Maps has no way of knowing where that is and what on-ramp is open. This is guesswork of the highest order, but in a week where my every movement was guided by Maps' algorithms, this was the only point of failure.

When I took that detour in Maryland, I was not alone; I counted at least eight vehicles taking that route along with me. Google offered me the choice, but this can't have been an option for every driver on a backed-up highway. I think there must have been a process of A-B testing, where some were rerouted and some were kept on the main road, and it used this information to decide where to send drivers later.

I don't often take these long drives, so it may be a year or two before I'm so fully in the hands of Google Maps and on such a dynamic journey, but I expect the experience to be even better.

2017/06/19

Feeling "Tipsy": The Perl Conference 2017 Day 1

A few lessons learned before I dive into the talks I attended and what I gained from them:

  • I had figured that aspects of my Every Day Carry would not be appreciated in a government building, so I left my multitool off my belt, but, even after I had put everything I could think of into the tray, I had still made the machines go beep, causing the guards to pull out the wand. Tomorrow, pack lighter.
  • I take notes on a paper notebook, but I used my phone and tablet to connect to others via IRC and Twitter, as well as keeping track of my calendar, and I ran through my batteries before the end of the talks. In part, it was switching between the local WiFi and the cellular network, doing well with neither, but I'm not convinced it'd wouldn't be drained regardless. At lunch, I need to find a place to charge. I often come with a power strip for just this purpose, too.
  • I didn't break out the laptop once. If I don't use it more, I should just leave it and have less to carry.
Hopefully, I will remember this and come prepared for the next one.

Now, to the talks:

I started the day with MetaCPAN, the Grand Tour. I had been convinced earlier that MetaCPAN is better than CPAN for looking into modules, but there's more, including modules I am going to have start using to search CPAN.  

Graham Knop's Continuous Integration for CPAN followed. I had been aware of Travis-CI, and had become aware of AppVeyor recently, but the tooling available in Perl to work with these was less familiar to me. I was unaware that you can specify Linux or OSX in Travis, This was something I was thinking and asking questions of other developers about. I have issues on FreeBSD, which I'm told is something that Gitlab-CI can help me with, but somehow, I doubt I can connect Github to Gitlab, but I could be wrong.

Steven Lembark had much more with Dockerizing CPAN Testers: Running an Isolated Test Site than I could fit into my head, and I think I'll have to go back to the tape once it's available, but I think it's a useful addition to the world.

After lunch, I went to Joel Berger's Variables, Scoping and Namespaces, which he set as a talk for beginners. He went so far as to suggest more established developers go elsewhere. Since I never thought I learned all of Perl when I was learning, it was very much a lot of things I did already know, but a little "So that's why we do that", some more "Oooh. I forgot about that", and one weird trick that explains how to mock functions for tests.

(That, fundamentally, is my big item to work on as a developer. Testing.)

After this, I attended Matt S. Trout's ES6: Almost an acceptable Perl 5? and it gave me a sense of treating Javascript like Perl, but since I don't code Perl like Matt does, I probably won't code ES6 like Matt does. My notes peter out about halfway through, but they do include several gems, such as lodash, that might improve the code I do write.

Following this is Lightning Talks, which has a bunch of interesting points, going from "Write for OpenSource.com" to "Try learning Dart" to "Creating Test JSON from JSON Schemas" to "Using Instapaper, IFTTT and Buffer to tweet what you read" to the Alien modules, which I almost understand now. Or maybe not. Certainly, though, I'd be installing and trying Dave Rolsky's RTx-toGitHub right now if I wasn't so tired.

Finally, Sawyer X talked about Perl 5.26 and the changes that came and the changes that are coming. The thing that comes to mind first is that things that have been deprecated since 5.0 are finally being pulled. I understand the critics who think that removing . from @INC is insignificant, but I am still for it. I also like that Perl recognizes unhandled merges and dies now. 

Tomorrow, I will be learning about Dancer, Test2 and more with @INC, and visiting with family after