One sometimes runs into problems with conflicting transitive dependencies. A dependency graph can help analyzing this. I use the sat-dependency-graph sbt plugin to help here. Just add to your plugins.sbt: addSbtPlugin(“net.virtual-void” % “sbt-dependency-graph” % “0.8.2”)   Running sbt task dependencyTree will do it: sbt dependencyTree If you like a bit more fancy, use the following to create a visual […]

Console JSON filtering with jq
10. June 2016

Consider a long list of JSON objects where you want to filter for different criteria. jq can be a big help here. See the following data: [ { “lat”: 50.559985870799224, “lng”: 8.478780446017911, “price”: 400, “dist”: 67.0682275804, “exposeId”: “1”, “ownerSsoId”: “100”, “rooms”: 2, “area”: 74 }, { “lat”: 50.58170215982231, “lng”: 8.45889590837296, “price”: 400, “dist”: 90.9399454663, “exposeId”: “2”, […]

Sending Mail without being considered SPAM
15. February 2016

Most websites will want to send mails one day. Usually people go the simple way and configure their CMS or whatever else to send mail using php’s mail() function. This works fairly well but without further work most of the mails being sent will be considered spam. This can have several reasons. Please ensure to do […]


I recently got an email of google informing me about a potential hack of a wordpress site I’m responsible for. It is presenting a massive amount of casino and cash load spam websites. Despite the fact that there is some kind of malicious code on my server, the loss of reputation for the website is […]

Here it is, a small and simple example on how to created presigned URLs for AWS S3 objects. #!/usr/bin/python import boto import argparse parser = argparse.ArgumentParser(description=’Generate an S3 signed URL’) parser.add_argument(‘bucket’, help=’bucket name’) parser.add_argument(‘key’, help=’prefix/key’) parser.add_argument(‘seconds’, type=int, help=’time in seconds until the URL will expire’) args = parser.parse_args() s3 = boto.connect_s3() bucket = s3.get_bucket(args.bucket) key = […]

I recently stumbled upon Netflix Vector, a nice tool for deep insights in system performance counters at high resolution. It is based on PCP ( for metrics collection which I wanted to have as RPM in version >= 3.10. Since then the pcp-webapi delivers CORS headers to allow running PCP and Vector on different ports/hosts. […]

AWS Resource Groups
18. December 2014

Some days before, a new button raised in my AWS Console, simply named “AWS”. It contains a nice Tag Editor allowing you to find resources and tag them (but you shouldn’t do this by hand, automate it!). From my point of view, resource groups are the much nicer feature. You can create a group and assign […]