Literally copying this post/note from a blog post by Nate Good http://nategood.com/quickly-add-and-edit-cookies-in-chrome
If you want to inset a cookie into a website request in Google Chrome, you can do it by launching developer tools (F12 in Windows) and typing the following in the console
javascript:document.cookie="myCookieName=myCookieValue"
varnishlog, one of the tools provided with varnish cache, uses VSL Query Expressions (https://www.varnish-cache.org/docs/trunk/reference/vsl-query.html) to provide some powerful insights into the requests and responses.
Here is a how you can use varnishlog to show all client requests that are ending up with a 404 response.
sudo varnishlog -g request -i ReqURL -q "BerespStatus != 200"
Technically, this particular query shows all client requests with a response other than 200.
Breaking down the commands
-g request : shows all entries related to the request
-i ReqURL : forces varnishlog to only display the Requesting URL
-q “BerespStatus != 200” : query filter to only match non 200 responses. Note that the query has to be enclosed in “”.
Quick how to on using awk to filter results if a certain value (column) is larger than a set value.
For example, if you have a file (servers.txt) with lines in this format
a_datacenter, servers 20 error, servers xyz b_datacenter, servers 21 c_datacenter, servers 50
and you want to show only the lines that have server value larger than 20, you can do this in awk by running
grep datacenter servers.txt | awk '$3 > 20 {print ;}' | more
breaking down the commands
grep – parsing down the output to just show the lines containing datacenter
awk – $3 > 20 : Get the third variable (awk seperates text using spaces by default) and check if it is greater than 20
print – print the entire line
It looks like I was able to accomplish writing the application that I wanted to on the App Engine in 2 days!! at least in it’s basic form. After some help from Google, I updated the application I created yesterday (http://samurai-apps.appspot.com/) to display the User Agent string being sent by the client.
The code has been updated to github at https://github.com/kudithipudi/google-app-engine/
Lessons from day 2?
Next, I will try to pretty it up a bit.
Isn’t it amazing that I was able to create a simple app in a matter of 2 days and host it on an “infinitely” scalable platform without even taking our my credit card.