Brennan Hitchcock

Thoughts, projects, stories and ideas.

Multiple Streams of income

I have always traded time for money. Whether in a regular 9-5 job or as an in-home computer technician. My 9-5 has its benefits for sure - health insurance, stability, comfort. Both my freelance and 9-5 have the same thing in common though - I am being paid for my time. I do love my job. The company I work for has a huge amount of flexibility with time off and hours worked and is challenging to the point of keeping me engaged without being burnt out.

Even given my ideal job situation I have been thinking about creating additional income streams for a few months. Initially, I set my goal to be $10.00 of passive income per month. As of today, I'm $2.39 of the way there. Yesterday, on July 9th, I published a UWP app on the Windows Store that allows users to use their Windows 10 device to control TP-Link smart plugs on their home network. Shameless plug (pun intended) - it's available here for 99 cents. Additional details and a screenshot can be found on my projects page. So far, the app has made three sales. THAT. BLOWS. MY. MIND.

I talked to a good friend that has a similar utility in the Microsoft Store and through conversation realized that over the past five years their app has been sold over 8,000 times. Dividing that out over 60 months that is ~133 copies sold per month on average. If my app performs anywhere near that level I will have exceeded my $10.00 a month goal by at least 10x.

Thank you for reading and if you like what I'm doing please feel free to check out any of my projects here.

Updating ESXI 6.7u1 to 6.7u2

Error:

[InstallationError][Errno 28] No space left on device
vibs = VMware_locker_tools-light_10.3.5.10430147-12986307

The solution is to manually upgrade VMware_locker_tools package by following these steps via SSH on the host:

  1. cd /tmp
  2. wget http://hostupdate.vmware.com/software/VUM/PRODUCTION/main/esx/vmw/vib20/tools-light/VMware_locker_tools-light_10.3.5.10430147-12986307.vib
  3. esxcli software vib install -f -v /tmp/VMware_locker_tools-light_10.3.5.10430147-12986307.vib
  4. Update / upgrade as normal

I recommend watching https://esxi-patches.v-front.de/ESXi-6.7.0.html for ESXI updates. Amazing resource.

One weird trick to use date dashboard filter on your custom SQL in Metabase

| Tags: metabase, tutorial

After participating a high-pressure sales meeting for one of the major BI vendors I stumbled upon an open source solution that covers 99.9% of our business use cases. When I evaluated this possibility several years ago there were no open source players in the field. Much to my surprise we found Metabase! From their site:

Metabase is the easy, open source way for everyone in your company to ask questions and learn from data.

We opted to self-host and had a test instance deployed within a few hours. The time from install to first dashboard was incredibly fast. The major benefit to this is that none of our data ever leaves our internal network.

Once our initial read-only dashboards were deployed we had additional reporting requests such that the user could analyze data over a period. No problem, there is a date filter available at the dashboard level. Unfortunately, most of my reporting is done using custom SQL and I couldn't seem to get these filters to work no matter what I tried. The documentation was vague on this point and however I tried to write a query I would get "Invalid Field" when trying to apply the dashboard filter to the card.

The resolution is simple. In your question create a field filter based on the date/time field that you want to filter by, in our case "CREATED_AT".

Question setup for date range filtering

By creating the field filter like this you allow the dashboard filters to inject their own SQL as appropriate for the type of filter you have. Allowed date/time filters currently include:

  • Month and Year - Like January, 2019
  • Quarter and Year - Like Q1, 2016
  • Single Date - Like January 1, 2019
  • Date Range - Like January 1, 2019 - January 8, 2019
  • Relative Date - Like "the last 7 Days" or "this week"
  • All Options (gives the dashboard user every option listed above)

Add the question you created to your dashboard, go into edit mode, and click "Add a Filter". Choose "Time" then choose the type of filter (listed above) you want to apply. In our example we used "All Options". Finally drop down the time field you want to use in each card.

Save your dashboard and enjoy your new dashboard filter. If this has been helpful please feel free to drop me a note and let me know!

AWS Users Group Meeting 5/17/2018: Doing things fast with ElastiCache

| Tags: meet-up

Last week I attended the local AWS users group meet-up. This was the first time with this group and naturally I was a little apprehensive. Luckily the pizza was amazing, the group was welcoming and the presentation was well executed and informative. Great job Scott! I've already got the next meet-up on my calendar.

ElastiCache is hosted/managed Redis and Memcached by Amazon. This allows developers to immediately use these technologies without provisioning and configuring servers. One negative though is that it must be used within Amazon's VPC (Virtual Private Cloud) and cannot be secured except for with instance level access lists.

For the demonstration our presenter, Scott, wrote a simple web application (in Ruby) that allowed for Widgets to be built by workers and then processed. Finally a CEO dashboard broke out a bunch of statistics about the work done, both today and historically.

Naturally in the small scale demo (< 10,000 widgets) the system ran great! Everyone was happy and the CEO could get their statistics. Enter a huge number of widgets. Suddenly worker productivity plummets. It takes tens of seconds to create a widget, over a minute to load the process screen and the CEO dashboard times out with an error. Now we have an upset CEO. Let's solve this by caching. By storing simple counts and last created widgets in ElastiCache Scott was able to simply fix both the worker and process pages (once the cache was warmed-up). The CEO dashboard proved to be a little more interesting as it required much more data in order for the cache to warm up. Once it was loaded (~3 minutes for a large number of widgets) then the CEO dashboard was once again happy.