Skip to main content

Karaf konffausta

Apache Karaf on OSGi standardin täyttävä valmis paketti valikoituja OSGi bundleja. Näppärinä ominaisuuksina mainittakoon mm. Felix gogo shell ja feature filet.

Feature fileillä voidaan määritellä mitkä bundlet asennetaan missäkin järjestyksessä. Olemme määrittäneet itse muutamia eri konfiguraatioita omaa softaa varten. Myös osasta karafin omista bundleista olemme hankkiutuneet eroon.

Karafissa on myös hyödyllinen maven-plugin jolla voi tehdä kustomisoidun karaf paketin. Käytämme tätä ominaisuutta, jotta saamme rakennettua paketin joka sopii aina testiympäristöistä tuontantoon. Kaikki konfiguraatiot, bundlet ja itse ympäristö on yhdessä tar-paketissa jonka voi purkaa ja ajaa missä vaan Java 8 koneessa.

Feature tiedostot ovat hyödyllisiä, mutta aiheuttavat myös harmaita hiuksia. Karaf parsiessaan ja asentaessaan bundleja (featureita) ei välttämättä anna kovin informatiivisia viestejä mikä on pielessä. Tämä tuli erityisen selväksi päivitettäessä karafia kolmosversiosta neloseen.

Muutama vinkki miten saada toimiva Karaf ympäristö aikaiseksi:


  • Aloita ensin pelkällä valmiiksi paketoidulla Karafilla ilman featurefileitä ja kokeile asentaa pelkästään yksittäisiä bundleja
  • Kun bundlet toimivat, tee yksi feature file joka voi olla myös bootissa ladattava
  • Jos käytät maven-pluginia, aja diffi sen tuottaman paketin sekä valmiiksi ladatun paketin välillä
  • Tarkasta aina lokaali maven repository ja vertaa sitä karafin system hakemiston sisältöön

Comments

Post a Comment

Popular posts from this blog

I'm not a passionate developer

A family friend of mine is an airlane pilot. A dream job for most, right? As a child, I certainly thought so. Now that I can have grown-up talks with him, I have discovered a more accurate description of his profession. He says that the truth about the job is that it is boring. To me, that is not that surprising. Airplanes are cool and all, but when you are in the middle of the Atlantic sitting next to the colleague you have been talking to past five years, how stimulating can that be? When he says the job is boring, it is not a bad kind of boring. It is a very specific boring. The "boring" you would want as a passenger. Uneventful.  Yet, he loves his job. According to him, an experienced pilot is most pleased when each and every tiny thing in the flight plan - goes according to plan. Passengers in the cabin of an expert pilot sit in the comfort of not even noticing who is flying. As someone employed in a field where being boring is not exactly in high demand, this sounds pro...
Post a Comment
Read more

Canyon Precede:ON 7

I bought or technically leased a Canyon Precede:ON 7 (2022) electric bike last fall. This post is about my experiences with it after riding for about 2000 km this winter. The season was a bit colder than usual, and we had more snow than in years, so I properly put the bike through its paces. I've been cycling for almost 20 years. I've never owned a car nor used public transport regularly. I pedal all distances below 30km in all seasons. Besides commuting, I've mountain biked and raced BMX, and I still actively ride my road bike during the spring and summer months. I've owned a handful of bikes and kept them until their frames failed. Buying new bikes or gear has not been a major part of my hobby, and frankly, I'm quite sceptical about the benefits of updating bikes or gear frequently. I've never owned an E-bike before, but I've rented one a couple of times. The bike arrived in a hilariously large box. I suppose there's no need to worry about damage durin...
Post a Comment
Read more

Emit structured Postgres data change events with wal2json

A common thing I see in an enterprise system is that when an end-user does some action, say add a user, the underlying web of subsystems adds the user to multiple databases in separate transactions. Each of these transactions may happen in varying order and, even worse, can fail, leaving the system in an inconsistent state. A better way could be to write the user data to some main database and then other subsystems like search indexes, pull/push the data to other interested parties, thus eliminating the need for multiple end-user originating boundary transactions. That's the theory part; how about a technical solution. The idea of this post came from the koodia pinnan alla podcast about event-driven systems and CDC . One of the discussion topics in the show is emitting events from Postgres transaction logs.  I built an utterly simple change emitter and reader using Postgres with the wal2json transaction decoding plugin and a custom go event parser. I'll stick to the boring ...
Post a Comment
Read more