Talent Shortage and Tech Salaries in the US

According to a report by Forrester

https://hackernoon.com/2018s-software-engineering-talent-shortage-its-quality-not-just-quantity-6bdfa366b899

Doing Things That Don't Scale

http://paulgraham.com/ds.html

It's more important than we think!

Market Share Comparison for Frontend JS Frameworks

React
VueJS
Angular

https://medium.com/existek/top-front-end-frameworks-in-2019-4c73c0f845d3

Article on Choosing AWS Regions

Link: https://www.concurrencylabs.com/blog/choose-your-aws-region-wisely/

Unicode References Especially Relating to Control Characters

• https://en.wikipedia.org/wiki/Unicode_control_characters
• https://unicodebook.readthedocs.io/good_practices.html
• https://en.wikipedia.org/wiki/Plane_(Unicode)
• https://www.soscisurvey.de/tools/view-chars.php
• https://japanese.stackexchange.com/questions/6872/are-the-4-byte-utf-8-kanji-rare-enough-that-i-can-ignore-them

VueJS Supported Web Browsers

VueJS supports all ECMA5 compliant browsers.

Use the following link to find out which these browsers are
https://caniuse.com/#feat=es5

Source: https://vuejs.org/v2/guide/installation.html

Articles About Building REST API Servers in Golang

• 7 Frameworks To Build A REST API In Go
• Building a RESTful API with Golang: Gorilla mux example
• How I structure production grade REST API’s in Golang: Chi example
• Building RESTful web API service using Golang, chi, and MySQL: Another Chi example

Articles Providing Overview of Golang

• Why Golang is Growing so Quickly
• Why Should You Learn Go?
• Why GoRoutines are not Lightweight Threads
• Tour of Golang Concurrency
• Why You can Have a Million GoRoutines

Vue Date Pickers

Blog article listing date pickers for Vue: https://madewithvuejs.com/blog/best-vue-js-datepickers

When to Hire a CTO

Excellent Article: https://www.techinasia.com/right-time-to-hire-cto

Things to "Give Up" to be Successful

Note to self: https://medium.com/thrive-global/13-things-you-should-give-up-if-you-want-to-be-successful-1958b5aaf116

Article About Startup Success Rates

https://www.techinasia.com/numbers-remind-startup-brutal

Startup Expansion Consultants

BOT is one of the models which they work on

Article: https://www.techinasia.com/talk/henek-lo

SKLearn Metrics Precision, Recall, F-Score and Support

Precision:

• If it's 1 it means all positives are correct
• It may be that many other positives for this class are wrongly labelled as negative (and categorised in other classes), but that's not measured in this metric
• The lower it is, it means more entries from other categories are being mis-classified here

Recall:

• If it's 1 it means it managed to find all the positive samples
• It may be that it wrongly classified other samples for other categories here, but that's not measured in this metric
• The lower it is, it means more entries from this category are being mis-classified into other categories

F-Score: Some kind of mean between precision and recall

Support: Number of occurrence in each category

Reference: http://scikit-learn.org/stable/modules/generated/sklearn.metrics.precision_recall_fscore_support.html

Article About Business Rules Versus Machine Learning

We usually program logic using business rules. However, there are cases where business rules are not clear cut and need continuous iterations to get right. This can be costly and difficult. In these cases, the machine learning approach might help.

Article: https://www.linkedin.com/pulse/data-science-machine-learning-vs-rules-based-karthik-guruswamy/

Data Shows Co-Founders are Not Absolutely Necessary

https://techcrunch.com/2016/08/26/co-founders-optional/

Resume SCP Transfer

No way to do in SCP. Use rsync:

rsync --partial --progress --rsh=ssh ec2-user@xxx.xxx.xxx.xxx:abc.tgz abc.tgz

Reference: https://yyab.wordpress.com/2006/12/18/resume-a-large-scp-transfer/

Tomcat Connections Getting Disconnected After Period of Inactivity

In some network environments, the firewall or router might terminate some connections after a period of inactivity.

However, this is not enabled by default:

# netstat -anpo | grep :80 tcp6       0      0 192.168.1.7:80      123.123.123.123:38123    ESTABLISHED 21345/java           off (0.00/0/0)

To prevent this, KeepAlive must be enabled in Tomcat. This is done by editing the Connector configuration in the server.xml file and adding the "socket.soKeepAlive" attribute.

<Connector port="8080" protocol="HTTP/1.1"               connectionTimeout="20000"               redirectPort="8443"                socket.soKeepAlive="true"         />

However, this alone may not be enough, because by default in some Linux distros, the default KeepAlive time is 2 hours, which means the first KeepAlive packet does not get sent until 2 hours later. For networks that disconnect idle connections within e.g. 15 minutes, this is too late. To reduce this to e.g. 5 minutes:

echo 300 > /proc/sys/net/ipv4/tcp_keepalive_time

Note: this change will not survive reboot. To make this change permanent the /etc/sysctl.conf needs to be edited.

After restarting Tomcat, the connection will look like this:

# netstat -anpo | grep :80 tcp6    0      0 192.168.1.7:80    123.123.123.123:38123   ESTABLISHED 21345/java      keepalive (82.52/0/0)

References:

• http://www.tldp.org/HOWTO/html_single/TCP-Keepalive-HOWTO/
• https://tomcat.apache.org/tomcat-8.0-doc/config/http.html

Ansible 2.2 with_items Deprecation

Prior to 2.2, this worked

- name: do something # do something here with_items: ec2.instances

However, this has been deprecated. Changelog item: "with_ 'bare variable' handling, now loop items must always be templated {{ }} or they will be considered as plain strings"

It's now required to do this:

- name: do something # do something here with_items: "{{ ec2.instances }}"

References:

• https://github.com/ansible/ansible/blob/devel/CHANGELOG.md#22-the-battle-of-evermore---active-development
• https://github.com/ansible/ansible/blob/devel/CHANGELOG.md#removed-deprecated

MongoDB: Setup Replica Set

Simple guide: https://blog.ajduke.in/2013/05/31/setup-mongodb-replica-set-in-4-steps/

Additional steps with keyfile auth:

• https://docs.mongodb.com/v2.6/tutorial/deploy-replica-set-with-auth/
• https://docs.mongodb.com/v3.2/tutorial/enforce-keyfile-access-control-in-existing-replica-set/