dracoblue.net

When Sam Newman's book (280 pages) on microservices was released in the first month of january 2015, I was already reading a preview edition for some weeks. Having the book as paper version next to my desk, let's me open it once in a while to find a good example for a concept or a piece of software for my microservices day work.

The book is not about indepth knowledge about every part of hosting lots of little connected systems, but gives such an awesome overview about all parts, that I can encourage everybody maintaining or creating systems and libraries to read this book!

After reading the spring boot reference in november, I wanted to know more in depth knowledge of spring data. That's why I read the official spring data jpa reference.

Something new to me is, that you can use _ in spring data repository interface names to give a hint to the query builder. So:

List<Person> findByAddress_ZipCode(ZipCode zipCode);
// resolves to address.zipCode or address.zip.code

When I was developing on http://web.twtxt.org I ran into this mysterious javascript error:

InvalidCharacterError: DOM Exception 5: An invalid or illegal character was specified, such as in an XML name.
atobbundle.js:245
(anonyme Funktion)bundle.js:245
emitbundle.js:1119
handlebundle.js:1673
onreadystatechangebundle.js:1465

The source code in question took a base64 encoded content of the github api and converted it with window.atob into an utf8 string.

This worked well except for safari on iOS!

If you want to check the status of your local single node elasticsearch development server, you can query the cluster stats endpoint at maybe http://localhost:9200/_cluster/health?level=indices.

{
  "cluster_name": "erstmal",
  "status": "red",
  "number_of_nodes": 1,
  "assigned_shards": 4,
  "unassigned_shards": 126
}

If this status shows "red" and you can see lots of unassigned_shards here, you have a problem.

When I was developing on the http-response-headers open source library for spring boot, I was curious how difficult it would be to make this available at maven central. And of course: everything should work automatically with travis ;).

To make your jars available at http://search.maven.org/, you can submit your open source project to "Sonatype OSSRH".

Basically you have 3 steps (OSSRH Guide):

1. Create a Jira Account at Sonatype
2. Create a Project Ticket
3. Deploy to https://oss.sonatype.org/content/repositories/snapshots or https://oss.sonatype.org/service/local/staging/deploy/maven2/. Therefor you need to:
   • Modify your pom.xml
   • Add build plugins for binaries, javadoc and sources jar files and gpg signing
   • Create a gpg key
   • Sign your builds
   • Integrate this with travis secured environment variables

The steps 1 and 2 took me some minutes and the response of the sonatype staff came a workday later. Nice.

Since I wanted to automate step 3, the following lines are more like a reminder for myself how I got this working. You can follow the following steps to set this up for your self, too.