Articles in the technology category

Drafts is a productivity app created by Greg Pierce (\@AgileTortoise).

I’ve loved and used Drafts 4 every day for the last several years. I loved it so much I even contributed to the Tip Jar Greg had in the app. Seriously, it’s an amazing app. If you haven’t downloaded it already you totally should.

Recently, Greg released Drafts 5. With this new version comes a new Business Model as well. Instead of a single pay (and hope people ‘tip’ you) he’s converted to a subscription model.

I signed up for the free week and didn’t have a real opportunity to use it before my free week was converted into a pay week but I’ve no regrets. I like what Greg does and want him to keep updating his app so that I can get the benefits of it once I have a real chance to dive in.

Part of the reason I wasn’t able to really use the new version is the way that I primarily use Drafts. I have a WorkFlow that takes a meeting on my work calendar and allows me to take notes about that meetings.

It’s one of the most useful productivity tools I have during my morning standup meetings with my team, and it’s useful for the other (sometimes endless) meetings that I go to.

With the release of Drafts 5 I was not longer able to use both Drafts 5 AND my workflow, so I needed to update my workflow.

With Drafts 4 it was just one of the built in Apps. Because Drafts 5 limits some of the functionality unless you have the PRO version I don’t think that Workflow will be updated to include Drafts 5 like it did Drafts 4.

Once I realized that AND since I’m paying for the app I figured I’d need to update my Workflow instead of waiting and hoping that Workflow would be updated to include Drafts 5.

In order to make the update I had to look for URL Scheme for Drafts 5 ... but I couldn’t really find one. I assumed that Drafts 5 URL Scheme would be the same as Drafts 4 (I was right) and made various attempts at getting a copy of the Workflow to work with Drafts 5.

This is the section of the workflow that needs to be updated:

Since Drafts 5 isn’t included in the Built in Apps I was going to need to pass a URL and open the app.

This would require 3 separate steps in Workflow

1. Convert Text into URL Encoded string
2. Prepend the URL Scheme for creating a new draft to the URL Encoded String
3. Open the URL

This basically means that 1 step is now replaced with 3 ... but hey, that’s the price of progress must be paid!

Both the Drafts 4 and Drafts 5 versions of these workflows are available.

If you enjoy them, hit me up in the comments or let me know on Twitter \@ryancheley!

Posted by ryan on Sat 19 May 2018

Logging into a remote server is a drag. Needing to remember the password (or get it from 1Password); needing to remember the IP address of the remote server. Ugh.

It’d be so much easier if I could just

ssh username@servername

and get into the server.

And it turns out, you can. You just need to do two simple things.

Simple thing the first: Update the hosts file on your local computer to map the IP address to a memorable name.

The hosts file is located at /etc/hosts (at least on *nix based systems).

Go to the hosts file in your favorite editor … my current favorite editor for simple stuff like this is vim.

Once there, add the IP address you don’t want to have to remember, and then a name that you will remember. For example:

67.176.220.115    easytoremembername

One thing to keep in mind, you’ll already have some entries in this file. Don’t mess with them. Leave them there. Seriously … it’ll be better for everyone if you do.

Simple thing the second: Generate a public-private key and share the public key with the remote server

From the terminal run the command ssh-keygen -t rsa. This will generate a public and private key. You will be asked for a location to save the keys to. The default (on MacOS) is /Users/username/.ssh/id_rsa. I tend to accept the default (no reason not to) and leave the passphrase blank (this means you won’t have to enter a password which is what we’re looking for in the first place!)

Next, we copy the public key to the host(s) you want to access using the command

ssh-copy-id <username>@<hostname>

for example:

ssh-copy-id pi@rpicamera

The first time you do this you will get a message asking you if you’re sure you want to do this. Type in yes and you’re good to go.

One thing to note, doing this updates the file known_hosts. If, for some reason, the server you are ssh-ing to needs to be rebuilt (i.e. you have to keep destroying your Digital Ocean Ubuntu server because you can’t get the static files to be served properly for your Django project) then you need to go to the known_hosts file and remove the entry for that known host.

When you do that you’ll be asked about the identity of the server (again). Just say yes and you’re good to go.

If you forget that step then when you try to ssh into the server you get a nasty looking error message saying that the server identities don’t match and you can’t proceed.

Posted by ryan on Sat 05 May 2018

Several weeks ago in Cronjob Redux I wrote that I had finally gotten Cron to automate the entire process of compiling the h264 files into an mp4 and uploading it to YouTube.

I hadn’t. And it took the better part of the last 2 weeks to figure out what the heck was going on.

Part of what I wrote before was correct. I wasn’t able to read the client_secrets.json file and that was leading to an error.

I was not correct on the creation of the create_mp4.sh though.

The reason I got it to run automatically that night was because I had, in my testing, created the create_mp4.sh and when cron ran my run_script.sh it was able to use what was already there.

The next night when it ran, the create_mp4.sh was already there, but the h264 files that were referenced in it weren’t. This lead to no video being uploaded and me being confused.

The issue was that cron was unable to run the part of the script that generates the script to create the mp4 file.

I’m close to having a fix for that, but for now I did the most inelegant thing possible. I broke up the script in cron so it looks like this:

00 06 * * * /home/pi/Documents/python_projects/cleanup.sh
10 19 * * * /home/pi/Documents/python_projects/create_script_01.sh
11 19 * * * /home/pi/Documents/python_projects/create_script_02.sh >> $HOME/Documents/python_projects/create_mp4.sh 2>&1
12 19 * * * /home/pi/Documents/python_projects/create_script_03.sh
13 19 * * * /home/pi/Documents/python_projects/run_script.sh

At 6am every morning the cleanup.sh runs and removes the h264 files, the mp4 file and the create_mp4.sh script

At 7:10pm the ‘header’ for the create_mp4.sh runs. At 7:11pm the ‘body’ for create_mp4.sh runs. At 7:12pm the ‘footer’ for create_mp4.sh runs.

Finally at 7:13pm the run_script.sh compiles the h264 files into an mp4 and uploads it to YouTube.

Last night while I was at a School Board meeting the whole process ran on it’s own. I was super pumped when I checked my YouTube channel and saw that the May 1 hummingbird video was there and I didn’t have to do anything.

Posted by ryan on Wed 02 May 2018

After days of trying to figure this out, I finally got the video to upload via a cronjob.

There were 2 issues.

Issue the first

Finally found the issue. Original script from YouTube developers guidehad this:

CLIENT_SECRETS_FILE = "client_secrets.json"

And then a couple of lines later, this:

% os.path.abspath(os.path.join(os.path.dirname(__file__), CLIENT_SECRETS_FILE))

When crontab would run the script it would run from a path that wasn’t where the CLIENT_SECRETS_FILE file was and so a message would be displayed:

WARNING: Please configure OAuth 2.0

To make this sample run you will need to populate the client_secrets.json file
found at:

  %s

with information from the Developers Console
https://console.developers.google.com/

For more information about the client_secrets.json file format, please visit:
https://developers.google.com/api-client-library/python/guide/aaa_client_secrets

What I needed to do was to update the CLIENT_SECRETS_FILE to be the whole path so that it could always find the file.

A simple change:

CLIENT_SECRETS_FILE  = os.path.abspath(os.path.join(os.path.dirname(__file__), CLIENT_SECRETS_FILE))

Issue the second

When the create_mp4.sh script would run it was reading all of the h264 files from the directory where they lived BUT they were attempting to output the mp4 file to / which it didn’t have permission to write to.

This was failing silently (I’m still not sure how I could have caught the error). Since there was no mp4 file to upload that script was failing (though it was true that the location of the CLIENT_SECRETS_FILE was an issue).

What I needed to do was change the create_mp4.sh file so that when the MP4Box command output the mp4 file to the proper directory. The script went from this:

(echo '#!/bin/sh'; echo -n "MP4Box"; array=($(ls ~/Documents/python_projects/*.h264)); for index in ${!array[@]}; do if [ "$index" -eq 0 ]; then echo -n " -add ${array[index]}"; else echo -n " -cat ${array[index]}"; fi; done; echo -n " hummingbird.mp4") > create_mp4.sh

To this:

(echo '#!/bin/sh'; echo -n "MP4Box"; array=($(ls ~/Documents/python_projects/*.h264)); for index in ${!array[@]}; do if [ "$index" -eq 0 ]; then echo -n " -add ${array[index]}"; else echo -n " -cat ${array[index]}"; fi; done; echo -n " /home/pi/Documents/python_projects/hummingbird.mp4") > /home/pi/Documents/python_projects/create_mp4.sh

The last bit /home/pi/Documents/python_projects/create_mp4.sh may not be necessary but I’m not taking any chances.

The video posted tonight is the first one that was completely automatic!

Now … if I could just figure out how to automatically fill up my hummingbird feeder.

Posted by ryan on Fri 20 April 2018

I’ve mentioned before that I have been working on getting the hummingbird video upload automated.

Each time I thought I had it, and each time I was wrong.

For some reason I could run it from the command line without issue, but when the cronjob would try and run it ... nothing.

Turns out, it was running, it just wasn’t doing anything. And that was my fault.

The file I had setup in cronjob was called run_scrip.sh

At first I was confused because the script was suppose to be writing out to a log file all of it’s activities. But it didn’t appear to.

Then I noticed that the log.txt file it was writing was in the main \` directory. That should have been my first clue.

I kept trying to get the script to run, but suddenly, in a blaze of glory, realized that it was running, it just wasn’t doing anything.

And it wasn’t doing anything for the same reason that the log file was being written to the \` directory.

All of the paths were relative instead of absolute, so when the script ran the command ./create_mp4.sh it looks for that script in the home directory, didn’t find it, and moved on.

The fix was simple enough, just add absolute paths and we’re golden.

That means my run_script.sh goes from this:

# Create the script that will be run
./create_script.sh
echo "Create Shell Script: $(date)" >> log.txt

# make the script that was just created executable
chmod +x /home/pi/Documents/python_projects/create_mp4.sh

# Create the script to create the mp4 file
/home/pi/Documents/python_projects/create_mp4.sh
echo "Create MP4 Shell Script: $(date)" >> /home/pi/Documents/python_projects/log.txt

# upload video to YouTube.com
/home/pi/Documents/python_projects/upload.sh
echo "Uploaded Video to YouTube.com: $(date)" >> /home/pi/Documents/python_projects/log.txt

# Next we remove the video files locally
rm /home/pi/Documents/python_projects/*.h264
echo "removed h264 files: $(date)" >> /home/pi/Documents/python_projects/log.txt

rm /home/pi/Documents/python_projects/*.mp4
echo "removed mp4 file: $(date)" >> /home/pi/Documents/python_projects/log.txt

To this:

# change to the directory with all of the files
cd /home/pi/Documents/python_projects/

# Create the script that will be run
/home/pi/Documents/python_projects/create_script.sh
echo "Create Shell Script: $(date)" >> /home/pi/Documents/python_projects/log.txt

# make the script that was just created executable
chmod +x /home/pi/Documents/python_projects/create_mp4.sh

# Create the script to create the mp4 file
/home/pi/Documents/python_projects/create_mp4.sh
echo "Create MP4 Shell Script: $(date)" >> /home/pi/Documents/python_projects/log.txt

# upload video to YouTube.com
/home/pi/Documents/python_projects/upload.sh
echo "Uploaded Video to YouTube.com: $(date)" >> /home/pi/Documents/python_projects/log.txt

# Next we remove the video files locally
rm /home/pi/Documents/python_projects/*.h264
echo "removed h264 files: $(date)" >> /home/pi/Documents/python_projects/log.txt

rm /home/pi/Documents/python_projects/*.mp4
echo "removed mp4 file: $(date)" >> /home/pi/Documents/python_projects/log.txt

I made this change and then started getting an error about not being able to access a json file necessary for the upload to YouTube. Sigh.

Then while searching for what directory the cronjob was running from I found this very simple idea. The response was, why not just change it to the directory you want. 🤦‍♂️

I added the cd to the top of the file:

# change to the directory with all of the files
cd /home/pi/Documents/python_projects/

Anyway, now it works. Finally!

Tomorrow will be the first time (unless of course something else goes wrong) that The entire process will be automated. Super pumped!

Posted by ryan on Tue 10 April 2018

I’ve been futzing around with SSL on this site since last December. I’ve had about 4 attempts and it just never seemed to work.

Earlier this evening I was thinking about getting a second Linode just to get a fresh start. I was this close to getting it when I thought, what the hell, let me try to work it out one more time.

And this time it actually worked.

I’m not really sure what I did differently, but using this site seemed to make all of the difference.

The only other thing I had to do was make a change in the word press settings (from http to https) and enable a plugin Really Simple SSL and it finally worked.

I even got an ‘A’ from SSL Labs!

Again, not really sure why this seemed so hard and took so long.

I guess sometimes you just have to try over and over and over again

Posted by ryan on Sat 07 April 2018

I previously wrote about how I placed my Raspberry Pi above my hummingbird feeder and added a camera to it to capture video.

Well, the day has finally come where I’ve been able to put my video of it up on YouTube! It’s totally silly, but it was satisfying getting it out there for everyone to watch and see.

Hummingbird Video Capture: Addendum

The code used to generate the the mp4 file haven’t changed (really). I did do a couple of things to make it a little easier though.

I have 2 scripts that generate the file and then copy it from the pi to my MacBook Pro and the clean up:

Script 1 is called create_script.sh and looks like this:

(echo '#!/bin/sh'; echo -n "MP4Box"; array=($(ls *.h264)); for index in ${!array[@]}; do if [ "$index" -eq 0 ]; then echo -n " -add ${array[index]}"; else echo -n " -cat ${array[index]}"; fi; done; echo -n " hummingbird.mp4") > create_mp4.sh | chmod +x create_mp4.sh

This creates a script called create_mp4.sh and makes it executable.

This script is called by another script called run_script.sh and looks like this:

./create_script.sh
./create_mp4.sh

scp hummingbird.mp4 ryan@192.168.1.209:/Users/ryan/Desktop/

# Next we remove the video files locally

rm *.h264
rm *.mp4

It runs the create_script.sh which creates create_mpr.sh and then runs it.

Then I use the scp command to copy the mp4 file that was just created over to my Mac Book Pro.

As a last bit of housekeeping I clean up the video files.

I’ve added this run_script.sh to a cron job that is scheduled to run every night at midnight.

We’ll see how well it runs tomorrow night!

Posted by ryan on Thu 05 April 2018

Last Wednesday if you would have asked what I had planned for Easter I would have said something like, “Going to hide some eggs for my daughter even though she knows the Easter bunny isn’t real.”

Then suddenly my wife and I were planning on entertaining for 11 family members. My how things change!

Since I was going to have family over, some of whom are Giants fans, I wanted to show them the ITFDB program I have set up with my Pi.

The only problem is that they would be over at 10am and leave by 2pm while the game doesn’t start until 5:37pm (Thanks ESPN).

To help demonstrate the script I wrote a demo script to display a message on the Pi and play the Vin Scully mp3.

The Code was simple enough:

from sense_hat import SenseHat
import os


def main():
    sense = SenseHat()
    message = '#ITFDB!!! The Dodgers will be playing San Francisco at 5:37pm tonight!'
    sense.show_message(message, scroll_speed=0.05)
    os.system("omxplayer -b /home/pi/Documents/python_projects/itfdb/dodger_baseball.mp3")


if __name__ == '__main__':
    main()

But then the question becomes, how can I easily launch the script without futzing with my laptop?

I knew that I could run a shell script for the Workflow app on my iPhone with a single action, so I wrote a simple shell script

python3 ~/Documents/python_projects/itfdb/demo.py

Which was called itfdb_demo.sh

And made it executable

chmod u+x itfdb_demo.sh

Finally, I created a WorkFlow which has only one action Run Script over SSH and added it to my home screen so that with a simple tap I could demo the results.

The WorkFlow looks like this:

Nothing too fancy, but I was able to reliably and easily demonstrate what I had done. And it was pretty freaking cool!

Posted by ryan on Sun 01 April 2018

Dr Drang has posted on Daylight Savings in the past, but in a recent post he critiqued (rightly so) the data presentation by a journalist at the Washington Post on Daylight Savings, and that got me thinking.

In the post he generated a chart showing both the total number of daylight hours and the sunrise / sunset times in Chicago. However, initially he didn’t post the code on how he generated it. The next day, in a follow up post, he did and that really got my thinking.

I wonder what the chart would look like for cities up and down the west coast (say from San Diego, CA to Seattle WA)?

Drang’s post had all of the code necessary to generate the graph, but for the data munging, he indicated:

If I were going to do this sort of thing on a regular basis, I’d write a script to handle this editing, but for a one-off I just did it “by hand.”

Doing it by hand wasn’t going to work for me if I was going to do several cities and so I needed to write a parser for the source of the data (The US Naval Observatory).

The entire script is on my GitHub sunrisesunset repo. I won’t go into the nitty gritty details, but I will call out a couple of things that I discovered during the development process.

Writing a parser is hard. Like really hard. Each time I thought I had it, I didn’t. I was finally able to get the parser to work o cities with 01, 29,30, or 31 in their longitude / latitude combinations.

I generated the same graph as Dr. Drang for the following cities:

• Phoenix, AZ
• Eugene, OR
• Portland
• Salem, OR
• Seaside, OR
• Eureka, CA
• Indio, CA
• Long Beach, CA
• Monterey, CA
• San Diego, CA
• San Francisco, CA
• San Luis Obispo, CA
• Ventura, CA
• Ferndale, WA
• Olympia, WA
• Seattle, WA

Why did I pick a city in Arizona? They don’t do Daylight Savings and I wanted to have a comparison of what it’s like for them!

The charts in latitude order (from south to north) are below:

San Diego

Phoenix

Indio

Long Beach

Ventura

San Luis Obispo

Monterey

San Francisco

Eureka

Eugene

Salem

Portland

Seaside

Olympia

Seattle

Ferndale

While these images do show the different impact of Daylight Savings, I think the images are more compelling when shown as a GIF:

We see just how different the impacts of DST are on each city depending on their latitude.

One of Dr. Drang’s main points in support of DST is:

If, by the way, you think the solution is to stay on DST throughout the year, I can only tell you that we tried that back in the 70s and it didn’t turn out well. Sunrise here in Chicago was after 8:00 am, which put school children out on the street at bus stops before dawn in the dead of winter. It was the same on the East Coast. Nobody liked that.

I think that comment says more about our school system and less about the need for DST.

For this whole argument I’m way more on the side of CGP Grey who does a great job of explaining what Day Lights Time is.

I think we may want to start looking at a Universal Planetary time (say UTC) and base all activities on that regardless of where you are in the world. The only reason 5am seems early (to some people) is because we’ve collectively decided that 5am (depending on the time of the year) is either WAY before sunrise or just a bit before sunrise, but really it’s just a number.

If we used UTC in California (where I’m at) 5am would we 12pm. Normally 12pm would be lunch time, but that’s only a convention that we have constructed. It could just as easily be the crack of dawn as it could be lunch time.

Do I think a conversion like this will ever happen? No. I just really hope that at some point in the distant future when aliens finally come and visit us, we aren’t late (or them early) because we have such a wacky time system here.

Posted by ryan on Mon 26 March 2018

Michael Kennedy over at Talk Python had a sale on his courses over the holidays so I took the plunge and bought them all. I have been listening to the podcast for several months now so I knew that I wouldn’t mind listening to him talk during a course (which is important!).

The first course I watched was ‘Python Jumpstart by Building 10 Apps’. The apps were:

• App 1: Hello (you Pythonic) world
• App 2: Guess that number game
• App 3: Birthday countdown app
• App 4: Journal app and file I/O
• App 5: Real-time weather client
• App 6: LOLCat Factory
• App 7: Wizard Battle App
• App 8: File Searcher App
• App 9: Real Estate Analysis App
• App 10: Movie Search App

For each app you learn a specific set of skills related to either Python or writing ‘Pyhonic’ code. I think the best part was that since it was all self paced I was able to spend time where I wanted to exploring ideas and concepts that wouldn’t have been available in traditional classrooms.

Also, since I’m fully adulted it can be hard to find time to watch and interact with courses like this so being able to watch them when I wanted to was a bonus.

Hello (you Pythonic) world is what you would expect from any introductory course. You write the basic ‘Hello World’ script, but with a twist. For this app you interact with it so that it asks your name and then it will output ‘Hello username my name is HAL!’ … although because I am who I am HAL wasn’t the name in the course, it was jut the name I chose for the app.

My favorite app to build and use was the Wizard App (app 7). It is a text adventure influenced by dungeons and dragons and teaches about classes and inheritance an polymorphism. It ws pretty cool.

The version that you are taught to make only has 4 creatures and ends pretty quickly. I enhanced the game to have it randomly create up to 250 creatures (some of them poisonous) and you level up during the game so that you can feel like a real character in an RPG.

The journal application was interesting because I finally started to get my head wrapped around file I/o. I’m not sure why I’ve had such a difficult time internalizing the concept, but the course seemed to help me better understand what was going on in terms of file streaming and reading data to do a thing.

My overall experience with the course was super positive. I’m really glad that I watched it and have already started to try to use the things that I’ve learned to improve code I’ve previously written.

With all of the good, there is some not so good.

The course uses it’s own player, which is fine, but it’s missing some key features:

1. Time reaming
2. Speed controls (i.e. it only plays at one speed, 1x)

In addition, sometimes the player would need to be reloaded which could be frustrating.

Overall though it was a great course and I’m glad I was able to do it.

Next course: Mastering PyCharm!

Posted by ryan on Tue 20 March 2018