Print stacktraces for all threads on shutdown

If your microservice stops responding from time to time, and they only way out is to kill it with SIGINT or SIGTERM then adding a shutdown hook might be the way to go. Do note that this will not work if you kill the process with SIGKILL (-9), cause that will result in an unclean shutdown.

Some of this code is heavily influenced by Print all of the thread’s information and stack traces : Exception « Development « Java Tutorial. But has been translated into Scala, and cleaned up a little.

The output would look something like this

 

Cassandra set the writetime explicitly with a PreparedStatement

This is a quick one, I wanted to set the writetime of a row explicitly when I populate the database for testing purposes. We use the writetime of a column to filter them out.

It required some looking around to find out how to do this…. so I figured I write an article about it.

The timestamp will be set for ALL cells in this row (well not the primary key, cause it does not have a timestamp, but the others).

The timestamp is given as milliseconds since EPOC, so lots of digits :-).

A prepared statement would then look like this (Scala code)

TTL and TIMESTAMP can both be set like this, i.e. with [ttl] and [timestamp]

-Tobias

SBT Good to know…

Dependecy problems

I have been having some difficulties figuring out what depends on what. I found the following set plugins which I think can be really helpful;

https://github.com/jrudolph/sbt-dependency-graph

and

https://github.com/gilt/sbt-dependency-graph-sugar

Be sure to install GraphWiz first, I used Homebrew on my Mac

brew install graphviz

and I also had to create a config file

with the following content

The readme explains how to use it pretty well, simply start sbt CLI

It will give you a graph that looks something like this (it is in SVG format so it is searchable!!!) Now you should see which package/jar is using which, and also where the different versions clash…dependency-graph

 

Show the class path for the run command