Recent Work

EarthQuick

Point Of Interests

I built this service through Github repo, having not used any cloud server, cloud database or even a single domain name. And I can assume that some day, some one may write a blog which telling us how to build a fully-functional backend service through Github .. :-) It may cost some time and work on both client and server side, maybe SDK or something, while simple write operation can be wrapped into simple Git operation, and use HTTPS to transmit operation to server or something ..

Ok, back to reality, what I gonna make is just a small and simple data fetching RESTful API: you can retrieve well formatted data from various different source with different format. Well, I run a script periodly on my useless Mac mini to execute the Python extractor and data processor every Five minutes in order to make sure the data update in time, then through git commit & push operation upload the constructed data to Github. Yes, every piece of data you get from this API is pre-processed on my Mac mini, and what you get is kind of a image of the data. So this is it - render locally, access remotely. (If you are willing to do more work on client side, it’s possible)

How to use launchctl run your script periodly on macOS

• Create your Shell script xx.sh in your work directory /Users/xxx
• Change permission of your script sudo chmod 777 xx.sh
• There are five destinations for you launch.plist file :

​ ~/Library/LaunchAgents per-user agents provided by specific user

​ /Library/LaunchAgents per-user agents provided by the administrator

​ /Library/LaunchDeamons Deamons provided by the administrator

​ /System/Library/LaunchDeamons per-user agents provided by OSX

​ /System/Library/LaunchDeamons Deamons provided by OSX

In which agents means application or script will only be running when specific user has logged in. When agents is provided by superior users, it means no matter user A or user B has logged in, this script will always be executed by this superior users. On the contrary, deamons means scripts can also be executed even when system has not been logged in. Here, the provider means you have to set the permission of the plist file in these directory to support only the specific user group can operate. For example, if you place your plist file in /Library/LaunchDeamons, you should

sudo chmod 600 sergio.chan.cron.plist

• Detailed description of parameters in launchd.plist can be found here
• Finshed plist file according to the documents, for example :

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>Label</key>
	<string>sergio.chan.cron.plist</string>
    <key>ProgramArguments</key>
    <array>
  		<string>/Users/xx/xx.sh</string>
    </array>
    <key>RunAtLoad</key>
    <true/>
    <key>StartInterval</key>
    <integer>300</integer>
    <key>StandardOutPath</key>
	<string>/../../Log.log</string>
    <key>StandardErrorPath</key>
	<string>/../../Error.err</string>
</dict>
</plist>

• Using launchctl command to control the script

launchctl load   /Library/LaunchDeamons/sergio.chan.cron.plist
launchctl unload /Library/LaunchDeamons/sergio.chan.cron.plist
launchctl start  /Library/LaunchDeamons/sergio.chan.cron.plist
launchctl stop   /Library/LaunchDeamons/sergio.chan.cron.plist
launchctl list

Notice that whenever you make any changes to the plist file, you should run unload first, then load again to make the changes effective. Rememer to enter full path of your plist file to guarantee the executed file is correct.

EarthQuick on macOS

Will come out sooooon.