Slackbot with AWS Lambda // Bourbon Blueberry Shrub

Slackbot with AWS Lambda // Bourbon Blackberry Shrub

If you're looking for the booze to give yourself a Ballmer peak, skip below...

The Code

Slack offers a ton of really neat integrations.  However, in the setting where I use it, most of them aren't an option.  Instead, I recently attended a coding night and spent some time rolling my own simple Slackbot using Amazon Web Services' Lambda and API Gateway features: Slackbroker!

Slackbroker is triggered using a slash command followed by a list of stock symbols.  It looks up the current stock price (or the closing price if the markets are closed) of each symbol, then posts publicly to the room where the slash command was run in the first place reporting the price.  There are a few barriers here thanks to the way slash commands work in Slack:

• Slash commands call a URL with a payload, but AWS Lambda needs to be invoked by its ARN
• The payload from a slash command is delivered in URL format (contrary to Slack documentation), but AWS Lambda demands input in JSON
• Slash commands respond by displaying a private message to the user who invoked them, but I wanted an individual to bring the whole group's attention to a stock

The Business Logic

To be frank, I finished this part last, but for the tutorial's sake I'll explain the entire Lambda contents here instead.  Lambda is pretty easy to set up - by default it accepts your code in its web editor.  While I can't fully get behind it for doing something significant with Lambda, it makes it convenient for small hacks like this.

It's in Python. lambda_handler is a special function that serves as the entry point executed when someone invokes your Lambda's ARN.  Because of the way the URL data is converted later, we get our content in a dictionary inside of event (also a dictionary) at entry postBody, which maps fields designated in the Slack documentation to their values.  

text is a string with everything following the slash command prompt typed in Slack; that is, if a user types /ticker abc def, text looks like 'abc def'.

channel_name is just that - the name of the channel the user was in when they invoked the slash command.  This is helpful to ensure you don't spam a general channel when you have Slackbot post back for you.

This weird URL is actually just a Slack incoming webhook.  They're pretty trivial to set up, so I won't really get into it, but this is the icky bit that lets Slackbroker post back to the entire group, instead of replying in a hidden message.

get_quote is a simple web scraper and is mostly stolen from a great StackOverflow post, but that code references an automatically-named tag in the regular expression - that is, that code only works for one symbol (and the tag name needs to be manually determined for that symbol to work).  I found that there was also a human-readable tag that contains the price, and referenced that in my regex instead.

pretty_quotes is a neat one-liner that uses join and a foreach to turn an array of strings into a single cute comma-separated list for human consumption.  I admit to lack of Python fu; an old classmate gave me a lot of help with this line.

Calling Lambda via URL

Luckily, AWS has a product called API Gateway that solves exactly our problem - it exposes (ugly) URLs that, when called, deliver the payload on to a specified ARN.  Here is how to make a new API Gateway and point it at your Lambda:

1. Create a new API through API Gateway.  Name it whatever, nobody will see it but you.
2. It looks pretty empty, so Create Method.  We want a POST with integration type Lambda Function.  Pick the region where your Lambda lives (this is found in the top right corner of the AWS console) and enter the name of your new Lambda.

Now you have a nice-looking flow diagram!  But it's not active.  Make sure you Deploy API, creating a new stage if you didn't have one.

Converting URL Data to JSON

We have a problem, though.  Slack will still send its data in a URL-encoded string, but Lambda expects JSON for it to turn into a Python dictionary!  Luckily, someone thought of this, and API Gateway allows you to write a converter between types.  Head to the Integration Request block of your API, expand Mapping Templates, and add a new one.  Content-Type refers to the type of the incoming data; in our case it's application/x-www-form-urlencoded.  Change the mode from Input Passthrough to Mapping Template; you will be presented with an editor to write your template.  We chose a pretty simple one; $input is a special value in the template.

{

  "postBody" : $input.json("$")

}

This defines what the event object from above will look like - we get an entry postBody that contains a map of all of our arguments from Slack.  Great, now we can actually invoke our Lambda correctly without it complaining about receiving literally anything besides JSON! (It's picky, isn't it?)

Adding Your Slash Command to Slack

We finally have everything ready to set up the Slack side of things!  To get ready, from your API Gateway console, you can use the Resources dropdown as shown here to select Stages; once you do so, choose the stage you created earlier.  Grab the Invoke URL from here.  

Then, head to my-team.slack.com/services/new and add a new Slash Command (way down in the DIY section).  Name it, and in the URL field, paste that Invoke URL from your API Gateway.  Leave the method as POST and customize the rest of the form as you see fit; save it and give it a whirl!

After following all these steps, you should have a working Slackbroker.  If I missed something, please let me know in the comments.  Good luck!

And hey -- do you need a drink after all that?  You're in luck, because so did I....

The Booze

A friend of mine started telling me about shrubs, these fruity vinegar syrups.  I tried making my own and it was none too pretty - somehow whatever I had created just made me feel sick every time I drank it!  But it tasted great, and my interest in shrubs didn't wane - I just decided to leave it to the professionals.  Recently I tried a blueberry lavender one at Finger Lakes Cider House in Ithaca, NY and it had to come home; I discovered it pairs great with bourbon!

Bourbon Blueberry Shrub

1.5 oz bourbon
.75 oz Good Life Cider blueberry-lavender shrub
club soda
ice

Fill a tumbler with ice. (Mine's a chilly Death Star!)  Add the bourbon and shrub; top with club soda and stir.  Condescendingly explain to all your friends what a shrub is and enjoy.

Finding a Majority to Be In

I think a lot about being the only woman. I talk a lot about it. It's one of the first things I notice when I work with a new team. How many women are there? How many men? What's the precise ratio?  No, seriously, I spend time in meetings with new teams or with aggregations of teams reducing fractions to find the exact ratio of men to women, what the percentage is, how much of the percentage I make up.  Partly that's because, well, it's a meeting, and as a coop, I don't get a merit increase, so I could care less that they'll be calculated by next Wednesday EOD, but mostly it's because I focus so heavily on gender in the workplace.

And that's wrong!

I shouldn't do that! It's sexist!

Because gender doesn't matter in a professional environment.  It doesn't define what I can do.  Just because I am the minority, a member of the group that has been wronged in the past, doesn't mean that that's all I am.  That's not what's most important about me.  What's important about me is that I'm a programmer, and I like low-level code, and I have experience with higher-level code, and I like skiing and hockey.  And tons more.  In fact, just about everything is more important than my chromosome set.  And even though I have a different chromosome set than the other 14 humans on my team, there's plenty of other stuff that I have in common.

So I am challenging myself.  Instead of counting gender ratios, I want to count numbers of majorities I am a part of.  I want to take note that I'm a member of the software developer majority.  The engineering background majority.  The hockey-watching majority.  The video-game-playing majority.

Because when gender matters more than all that other stuff, that's sexism, period.  When any attribute - attractiveness, race, sexuality, nationality, whatever - that you didn't opt into matters more than all the other stuff that you did opt into, that's bigotry.  In the workplace, on TV, dating, at school, anywhere.

So, let's quit it.  The American dream is that people can be whatever they want to be, right?  That people can choose who they are.  And I don't think America is too different from the rest of the world, not any more. None of us have an excuse to focus on something we can't help unless someone else did it first, and then only to find equality and fairness.

sscanf() Gotcha

Interesting gotcha I ran across using sscanf() today.

Here's the example scenario.  In my case, I was parsing a .mcs file and looking for pairs of characters that were hex representations of bytes of data.  That is, the string "FF001122" would translate to data = {0xFF, 0x00, 0x11, 0x22}.


fstream stream;
stream.open(fileLoc);

char data[8] = {};
char line[16];
stream.getline( line, 16 );

for (int i=0; i<8; i++) {
    sscanf( line + (i*2), "%2x", &(data[i]) );
}


Upon program exit, I get a stack corruption error around 'data'. Weird, right? We don't go out of bounds at any point on data, right?

Well, we don't... But sscanf() is a different story.

Let's step through the for loop.  We'll say line = "0011223344556677".

i=0.
data = { ?, ?, ?, ?, ?, ?, ?, ?}
Perform the sscanf.
data = { 00, 00, 00, 00, ?, ?, ?, ? }

See the problem yet?
We'll keep going:

i=1.
data = {00, 00, 00, 00, ?, ?, ?, ?}
Perform the sscanf.
data = {00, 11, 00, 00, 00, ?, ?, ?}

At the end, we have:

i=7.
data = {00, 11, 22, 33, 44, 55, 66, 77} 00, 00, 00 (out of bounds!!!)

What's going on here is that sscanf() doesn't realize that data is an array of chars.  It assumes that since the "%x" identifier was used, we want it to give us unsigned ints.  But it doesn't check, or ask.  Turns out there's a way to specify manually - the correct form to receive data back in char size (and thus write out of bounds) is to use the identifier string "%2hhx" - that is, 2 hex chars output into one byte of data (specified by the "hh").  If you look carefully, the scanf formatting table in the spec tells you that this is expected behavior, but it's not particularly outspoken about it.

So, keep an eye out, from your good friend Emily, wasting four hours of her day so you don't have to.

EDIT:
Turns out this doesn't quite work depending on your architecture and whether or not you're using Unicode.... I ran this same code in Unicode and the 'hh' format string doesn't help - sscanf still reads into 4 bytes every time.  Internet searches show that the best solution is to use a temporary variable. Barf.

Automatic Android App Builds with Github, Travis and Ant

Continuous integration is awesome.  Android is okay, I guess.  Both together is pretty darn cool.

If you're using a version control system, which you should be, you may be interested in automatically building your project every time you push a change to your repository.  You can do this in a few ways - traditionally, you can host a Hudson or Jenkins instance on your local machine and set up a commit hook that tells your CI instance that it's time to go make a build.  Your CI bot will then go fetch the source from your new commit and build it, then report the results to you.  However, then the build is still using your PC's resources, so there's not that much benefit (especially if someone somewhere else pushes to your repository with the correct commit hook unexpectedly).  If you have your own server somewhere, you can use that, problem solved...

Not all of us do, though - and for that there are a few sites that will host for you.  One is CloudBees (which I have not used and will not talk about), and the other is Travis, which I did use, and will talk about.

Travis is tightly integrated with GitHub, and doesn't expose a buildbot like Hudson or Jenkins.  It doesn't expose its service hooks, either, so as far as I can tell, it doesn't support hooking into repositories that aren't hosted on GitHub - if you want to use it, you need to mirror your source to GitHub.

That said, it is incredibly easy to use with GitHub.  Simply sign in with your GitHub credentials on the Travis website - in your account properties you can "switch on" projects that you want Travis to build on commit.

Travis uses a single descriptor YAML file named .travis.yml in the root directory of your repository to execute the build.  Your .travis.yml defines which language Travis should use to build, where, and which pre- and post-build steps to take.  A list of supported languages can be found on the Travis documentation here.

In the case of Android projects, Travis does not come with the Android SDK, so you need to download the SDK and the correct Android release libraries yourself in the prebuild by specifying a before_script.

before_script: 

    - sudo wget -q http://dl.google.com/android/android-sdk_r18-linux.tgz 

    - sudo tar xzvf android-sdk_r18-linux.tgz > /dev/null

    - sudo android-sdk-linux/tools/android -s update sdk --filter android-7,platform-tool --no-ui

    - sudo android-sdk-linux/tools/android -s update project --path ./FridgeMagnet --target "android-7"

    - sudo android-sdk-linux/tools/android -s update test-project --path ./FridgeMagnetTest -m ../FridgeMagnet

I'm building my project based on Android 2.1, so I am downloading android-7 (Android 2.1).  android update takes an ID to determine which packages to download - you can see a list of the correct IDs for each available package using android list sdk and specify which packages to download using the --filter argument.  platform-tool is needed to build with ant.  android update project sets up the ant build.xml for each project - needed for the next step. In some cases,  you may find that the permissions in your Travis environment are limiting, so I use a big hammer and simply add:

- sudo chmod -R 777 ./*

at the bottom of my before_script.

Travis downloads source to a non-persistent environment with every push, so it is necessary to download the SDKs every time.  This is the suggested method.

Next we want to actually build, using ant.  You can specifiy your build script under script: in your .travis.yml.  In the most simple case you can simply specify:

script:

    - cd ./FridgeMagnet

- ant clean

- ant debug

If you have more than one project build, you can use a bash script as your script: action instead of specifying each action in the .travis.yml - otherwise if one project build fails, Travis will stop the build process completely.  You can then return the success status from your script so Travis knows whether your build ran correctly or not.

#!/bin/bash

FAILED=0

cd ./FridgeMagnet

ant clean

ant debug

if [ "$?" = 1 ]; then

    echo "FridgeMagnet build failed!"

    FAILED=1

fi

cd ..

exit $FAILED

Now you should be able to see your builds on Travis as they are built under http://travis-ci.org/#!/githubusername/GitHubProjectName.

For an example, my project FridgeMagnet can be found on GitHub and Travis.

Feminine Wiles

I'll be outright.

Every time I want to make friends with males in my major, I feel pressured to prove myself.  I feel pressured to make sure they know I work for my own success and am capable in my field.  I don't feel that I will be respected without making it known I excel in my field.

I'm sick of this.  I'm sick of feeling like every new friend is another point to prove, and every first impression is against me.  I strive to present myself in a way that first impressions of me are positive and respectful, and I have infinite doubts as to this work's payoff.  I still feel as though I have a number of stereotypes to overcome: unmotivated, unwilling to learn, airheaded, flippant, and more.  It sucks fighting against those stereotypes.

(A quick aside, as an exercise to the tech-student reader.  Ask yourself, "Do I feel that women in tech fields are any of those things?"  Now, disregard your politically-correct heavily-generalized answer and ask yourself, "What do I think of the women in my tech classes?"  Ponder on that for a moment.)

But it sucks even more that those stereotypes are there in the first place.  It sucks that there were enough women in technical fields before me who fit those traits to form a stereotype.  And of course, it sucks that the behavior of those women should have any bearing on me.

I'm interested in talking about why women have stereotypes like this.  I think it has to do with these so-called "feminine wiles" - a shift of the blouse and a wink of the eye, and a good-looking woman has the world at her feet, so we're told.  And it works, often enough, for the same reason that a glance-over and a cute smile can get plenty of men whatever they want with us - humans like feeling wanted, but that is neither here nor there.  Using these feminine wiles, to me, seems akin to using a CAS calculator on the ACT.  Yes, you can probably get away with it.  Yes, it will probably work out well for you.  But morality aside, you won't learn anything and you won't represent yourself accurately.  You aren't showing any real skills.  And if you're caught, you're up shit creek.

Men are easy, in some fields more than others.  The fields themselves are not!  Sure, you can get help with your homework and breeze through freshman year with the assistance of your reverse-harem.  But what will that do for you?  It will ensure that you have a shaky background for the next year, and the year after that, ad nauseum.  And it will build you a reputation, which will in turn build your gender-specific peers a reputation.  Your easy way through engineering school is leaving behind red shells for everyone who comes after you.  It's a dangerous game to play, and most of the time it'll bite you in the ass - imagine, years later, you apply for a job at Company Foo.  The recruiter at Foo says to student Bob, who he knows went to school with you, "What do you think of this person who we are thinking of hiring?"  If Bob says, "Well, she didn't do much work in college - usually she had a boyfriend do her work for her," this is a problem.  This is a reputation that you will not be able to get rid of, even if you fix your experience and your skill base after graduating!

My plea here has a dual nature.  Women, and men, everyone: please think long and hard about the way you present yourself to the world, and about any and all effects your demeanor has on what people think of "your kind".  And women, men, everyone: please, if you catch yourself making a snap judgement of someone and they fit a negative stereotype - take notice and ask yourself what you have observed to allow this judgement.  Please don't fear the benefit of the doubt - let your peers prove themselves guilty if they so are.  It's much easier than proving oneself innocent.

There are more "wiles" than this blatant example, though.  A wise piece of advice was once offered to me - the giver admonished that instead of striving to prove myself to every male I meet, I should instead stay passive and agreeable.  She suggested that if I compete to prove a point with every male, most will insist on winning for their pride's sake, and would continue competing until they win.  She suggested that I essentially lay low and do my own thing unobtrusively.  And yeah, that sounds like a pretty effective strategy - but a cowardly one.  I'm young and I'm outspoken and I want to make it known that I know what I'm doing.  I don't want to hide my talent because of my chromosomes.  I don't see a reason that I should have to.  Some men have competitive natures, some have unobtrusive natures, so why should I hide my competitive nature if I have one?  Please, please - give me a good reason.

I have a deeper concern, though, than my own selfish concern - and that is that hiding talent could easily be transposed into letting talent go unused.  It is absolutely true that if you don't use it, you lose it.  So what does that say about the long-term benefits of women hiding their intelligence, interests, assertiveness, and talent?  By being unobtrusive, are we allowing society to perpetuate our own downfall?  The statistics already aren't in our favor, so why shouldn't we do anything and everything in our power to keep them from getting worse?

On Women in Magic

Engineering classes are not the only important aspect of my life where I make up the small end of the ratio.  I also play Magic: the Gathering semi-competitively, attending tournaments and sealed events when time and money allow.  Today I'd like to touch on women in Magic.

It is common for me, especially in the tiny town where I grew up, to enter a venue for a Magic tournament and be either the entirety or one-half of the female representation out of 15 to 20 competitors. And when I enter a venue I haven't been to before or play an opponent who has never met me, I am invariably asked some form of the same question: "Is this your first time playing?"  The frequency of this question baffles me.  I have well-worn card sleeves on my deck, a playmat, a handmade dicebag full to the brim, and have memorized my DCI number - not exactly the trappings of someone just entering the game.

These players are trying to be polite.  They are interested in giving me a good impression, so that I return, and they have decided to err on the side of safety - figuring the assumption that I don't know how to play and am using a borrowed deck with borrowed accessories is a safe one.  Without a second thought, they have tagged me as a player's girlfriend - convinced into trying the game in order to make her boyfriend happy.

I can't even be personally offended.  I try very hard to present myself as someone who is a nerd of her own accord, but it is an uphill battle.  The fact remains that the vast majority of females at my level of competitiveness are playing because their boyfriend got them into it, and don't care enough about the game to put forth real effort.

But one must wonder - what about the girls who started playing Magic competitively and did care?  Where are they in this picture?  In over a year's worth of casual tournaments, in a significant number of cities, and a few hundred participants, the number of girls I have met who play competitively for themselves could be tallied on one hand.    This number combined with the number of seriously competitive girls who started playing because of a significant other but continue for themselves is barely higher.

The ratio of males who play at my level to females who play at my level, in my experience, has been astronomically higher than any male to female ratio I have encountered elsewhere.  Why are there so few women who take Magic seriously?  Is it rudeness? I don't think so - assholes as Magic players generally are, I have not seen many instances of outright verbal sexism.  Harassment?  Maybe - a player once gave himself a good fondling with my coffee to-go cup at a midnight release, and I can't say the experience was a fun one.  In general, the mood of these men generally reflects that they aren't offended by that sort of 'man humor,' and a lady can tell.

Mostly, though, I think it the reason is a subtle one.  Magic players never, ever, ever regard a female opponent as a threat until they have been proven otherwise.  They play against us casually, offering us friendly mulligans and do-overs, confident that they can win no matter how much of a handicap we are given.  They don't even try to hide that their first opinion of a woman across the table from them is "easy win," and it takes the rug from under us ladies before we can even fully stand.  A woman participating in entry-level competitive Magic is instantly dismissed, and she can tell - she is thrust into a negative, hostile environment and must fight tooth and nail to prove herself.

This is appropriate here.

Does she have inspiration, should she look to the stars?  Unfortunately, not really - though there are a large number of developers and designers at Wizards, they are largely in the shadows.  No woman has ever top-eighted a Pro Tour.  Though women occasionally rank or finish first in Nationals and Grand Prix, they are few and far between.  No woman has reached the quasi-household-name status of greats like LSV or Chapin.  Highly-publicized all-female Magic teams like the Mana Girls, while they do exist, are gimmicky at best.

The Mana Girls, complete with matching uniforms. Cute.

So, I believe that very question that I am asked, so often and so strangely - "Is this your first time?" - is a lot of what is wrong with gender equality in Magic.  To my male readers, I bequeath you to watch your own behavior.  Give us the benefit of the doubt.  Though it sounds the same, and indeed accomplishes the same answer, I encourage you instead to ask along the lines of "How long have you been playing?" or "How do you usually do at these things?"  We'll tell you if we're new - but we don't need you to assume it. Allow us to set our own first impression to you, at whatever play level we truly are, instead of making one for us.

"Wouldn't Bang"

 

I spend most of my time on the Internet, between working at my IT help desk job, perusing how-tos at home, and talking to my far-flung friends and family.  As such, I have developed a fondness for memes of all kind (I'm on a big Advice Animals kick right now).  I have a pretty good sense of humor, and am not easily offended, but I have noticed a trend that is disheartening to me: Wouldn't Bang.

It's cute on the outside - the socially helpless Dweller cites a meaningless flaw as a reason not to have sex with a woman who, let's face it, would never even offer.  The audience has a good laugh because it's obvious that, if it were offered, the Dweller would bang, and in a heartbeat.  These are generally harmless, citing minor flaws in appearance or preference.  However, some speak more deeply, listing failings in nerdiness or technical knowledge - take the example above.

I am a nerd girl.  I use Linux as my sole operating system (not even on a dual boot).  I program, and enjoy it.  I own a PS2, PS3 (original, fully backwards-compatible 20GB with a 500GB hard drive upgrade), Xbox 360, and (hacked) PSP.  I cosplay, Joss is my master now, xkcd is my favorite webcomic, and I play Magic: the Gathering competitively.  By my count, that's five genres of nerdiness thus far - let's go ahead and add that I'm a computer engineering major and that I started working in IT when I was a junior in high school, at which time I was also a percussionist in the band.  Convinced?

These are the types of nerd I am - computer, gaming, Magic, Whedonite, band, anime, engineering.  I am not, however, the following types of nerd: DC, Marvel, Star Trek, Star Wars, WoW, chess... the list goes on.  The point I am trying to make is thus: not everyone is a polymath.  I engage in more genres of nerdery than most people I know - that's how I choose to broaden my horizons - but there remain gaps in my knowledge.

Keeping this in mind, let's look at the following scenario.  A woman is conversing with a man about Linux, a field in which she has much experience.  She makes educated arguments and, in general, displays a working knowledge of the subject matter.  The subject then shifts to computer hardware, and the woman shows again that she knows what she's talking about.  It's obvious that she is intelligent.  Let the conversation take a sudden turn to comics - the man asks her favorite character, and she names Power Girl, making a comment wondering whether Green Lantern would appear as a crossover in a Power Girl film.

She thinks Power Girl is a Marvel creation?

Wouldn't bang.

This woman is trying to create an impression of herself as a knowledgeable nerd, on equal ground with the men around her.  With one step into unfamiliar territory, she has destroyed her work.  Held to incredible standards, she has made a mistake, and her entire reputation has suffered.

A man in the same situation? "Sorry bro, I don't read comics - I got laid in high school instead!" No harm done.

As a female in a male-dominated area, I feel a great pressure.  Don't screw up, or you'll embarrass your entire half of the human race.  Don't make the rest of us look bad.  Make a mistake and give all women a bad name among these men.  "Wouldn't Bang" concerns me because it is an enforcement of these pressures.  Sure, she may be the top programmer in my class, but she hasn't seen Dr. Who?  Wouldn't bang.  So she can quote from any issue of Batman ever written, but she runs Windows?  Wouldn't bang.

I have acute perfectionism forced upon me by my surroundings.  It is one thing to choose yourself held to unattainable standards; that is called drive.  But to have these same standards externally placed on you, when others may choose?  That, readers, is called inequality.