Software - KobelNET Blog

Avoid constraint errors when running parallel pg_restore

From Moritz Kobel

Created 13.07.2022

Last updated 31.10.2022

To enhance the restore speed for PostgreSQL databases, the pg_restore command running the most time-consumping steps concurrently by providing the number of jobs with -j/--jobs.

Unfortunately the parallel restore can fail when restoring foreign keys due to not yet restored tables:

pg_restore: error: could not execute query: ERROR:  there is no unique constraint matching given keys for referenced table "page"
Command was: ALTER TABLE ONLY pagecontent
    ADD CONSTRAINT "$1" FOREIGN KEY (page_id) REFERENCES page(id);

PostgreSQL

Old Let’s Encrypt Root Certificate Expiration workaround

From Moritz Kobel

Created 30.09.2021

Last updated 01.11.2022

In Software

The expiring Let’s Encrypt DST Root CA X3 can cause problems on old servers:

root@server:/etc# wget https://www.example.com/monitoring
--2021-09-30 21:34:39--  https://www.example.com/monitoring
Resolving www.example.com (www.example.com)... 93.184.216.34
Connecting to www.example.com (www.example.com)|93.184.216.34|:443... connected.
ERROR: The certificate of `www.example.com' is not trusted.

Fortunately there is an easy workaround to ensure the expired chain is not checked.

Debian Linux Network SSL

Configuring an Unify Dream Machine for Swisscom 6RD IPv6

From Moritz Kobel

Created 09.07.2021

Last updated 01.11.2022

In Software

The residential Swisscom Internet Box 2 does not allow to autoconfigure an Unify Dream Machine with IPv6.

After several hours of research I found a workaround to get IPv6 support.

Network Unifi

Workaround for missing DomainClassConverter in Spring Boot JUnit tests

From Moritz Kobel

Created 16.08.2020

Last updated 01.11.2022

In Software

In one of my projects I let Spring Boot automatically bind domain objects from the database.

This fails in the reduced unit test setup, because DomainClassConverter is not available. But it can be mocked!

Java Spring Boot Web

Avoid conversion warnings when using yedit ansible role

From Moritz Kobel

Created 27.02.2020

Last updated 01.11.2022

In Software

When I fist started to use yedit to modify YAML files I got the following warning:

[WARNING]: The value {...} (type dict) in a string field was converted to "{...}" (type string). If this does not look like what you expect, quote the entire value to ensure it does not change.

Ansible

Shrinking LVM physical volume running on software RAID

From Moritz Kobel

Created 24.02.2020

Last updated 01.11.2022

In Software

Due to a misconfiguration I had to shrink a LVM 2 volume group and its physical volume running on a software RAID.

Debian Linux RAID

Formatting phone numbers using libphonenumber in Thymeleaf

From Moritz Kobel

Created 08.01.2020

Last updated 01.11.2022

In Software

The Google phone number parser & formatter is very helpful to ensure the same number format for user prodived data. To simplify the use in Spring Boot application with Thymeleaf I created a wrapping TagLib/ExpressionFactory.

Java Spring Boot Thymeleaf

Samsung SSD as Linux Software RAID

From Moritz Kobel

Created 29.12.2019

Last updated 01.11.2022

In Software

Initially I thought adding a pair of Samsung 860 EVO as software RAID to my small home server cannot be too hard...

... but they seem to require special kernel settings to work.

Debian Linux RAID Samsung SSD Ubuntu

Setup Unifi Controller on Debian 10 / Buster

From Moritz Kobel

Created 06.12.2019

Last updated 01.11.2022

In Software

The requirements of the Unifi Controller do not allow a direct installation. But with a few manual steps a successful setup is possible!

Debian Unifi

How to ensure you get a BindingResult instead of whitelabel error page when validating input

From Moritz Kobel

Created 03.05.2019

Last updated 01.11.2022

In Software

When I started to use Spring Boot I had some issues with the validation. The @Validated annotation triggered the validation as requested but the validation terminated with an org.springframework.validation.BindException instead of filling the BindingResult object.

Java Spring Boot Web

Configure Java/JDBC to connect to PostgreSQL with JRE certificate validation

From Moritz Kobel

Created 02.05.2019

Last updated 01.11.2022

In Software

Using the PostgreSQL JDBC driver since 42.2.5, the SSL behaviour changed which can cause FileNotFoundExceptions looking for .postgresql/root.crt.

Java PostgreSQL

Configure Apache as Proxy for Thumbor

From Moritz Kobel

Created 01.05.2019

Last updated 01.11.2022

In Software

On our default setup, we use Apache as proxy and load balancer for our applications. This usually works, but caused problems with Thumbor.

Apache Thumbor Web

Inject Attributes to Spring Boot Controller Methods (HandlerMethodArgumentResolver)

From Moritz Kobel

Created 15.03.2019

Last updated 01.11.2022

In Software

During learning Spring Boot I noticed attributes to methods in Spring Boot controllers can be automatically injected.

To migrate my blog from Grails to Spring Boot I created an implementation to inject the current blog instance based on an session attribute.

Spring Boot Web

Asset Pipeline Thymeleaf Taglib

From Moritz Kobel

Created 12.03.2019

Last updated 01.11.2022

In Software

Using the asset pipline in Grails, the production CSS and Javascript files have been including with a digest appendix. This feature is not available in Spring Boot, therefore I started to create a simple Thymeleaf tag library.

Asset pipeline Spring Boot Thymeleaf Web

SSL Debugging with Arduino / ESP8266

From Moritz Kobel

Created 14.06.2018

Last updated 01.11.2022

In Software

I recently bought the 2.9″ ESPaper Plus Kit, WiFi ePaper display from ThingPulse.

To get this device working with my ansible configured SSL webproxy I had to get some additional debugging skills...

Arduino Debug ESP8266 SSL Web

How to find the cause of "deleted object would be re-saved by cascade"

From Moritz Kobel

Created 21.11.2017

Last updated 01.11.2022

In Software

Sometimes if you do not properly delete objects in a Grails/GORM/Hibernate transaction the following error might occur:

deleted object would be re-saved by cascade (remove deleted object from associations)

This message is presented by the org.hibernate.ObjectDeletedException

After some hours of investigation I found a solution to find the cause!

Grails Java

MCabber Notifications in i3

From Moritz Kobel

Created 19.11.2016

Last updated 01.11.2022

In Software

On my new i3 setup I got no notifications of new MCabber events and messages.

Arch Linux i3-wm MCabber

Setup CyanogenMod on Google Nexus 10

From Moritz Kobel

Created 13.11.2016

Last updated 01.11.2022

In Software

Due to the decreasing performance of Android on my Nexus 10 and similar reports of other user I tried to install CyanogenMod 13. This caused some resolvable problems...

Android CyanogenMod Nexus 10

Seafile behind a proxy

From Moritz Kobel

Created 10.11.2016

Last updated 01.11.2022

In Software

My Seafile instance is running on a dedicated webserver behind a reverse proxy which is handling the SSL encryption.

This setup with the protocol change on one of the webservers does not work out of the box / this case is not documented in the official server documentation.

Apache Network Proxy Python Seafile Ubuntu Web

BASIC Auth with Oracle WebLogic

From Moritz Kobel

Created 05.04.2016

Last updated 01.11.2022

In Software

If you would like to do the authentification in Java application running on Oracle WebLogic, you will probably wonder why the Authentification-Header does not reach the Filter.

Java

Logstash Log4j broken pipe with MDC attributes

From Moritz Kobel

Created 30.06.2014

Last updated 01.11.2022

In Software

We recently configured some applications to log with log4j's SocketAppender to Logstash.

When we startet to add MDC-Attributes we sometimes lost the connection:

| Error log4j:WARN Detected problem with connection: java.net.SocketException: (broken pipe)

Debug Grails Java Log4j Logstash

PDF nach Scan umwandeln

From Moritz Kobel

Created 01.02.2014

Last updated 01.02.2014

In Software

Beim Duplex-Scan mit hp-scan erstellt mir die Software ein PDF-Dokument, wo auf allen Seiten unten ein weisser Rand ist und jede zweite Seite um 180 verdreht ist.

Zum Glück gibt es Tools, welche diese Probleme in wenigen Schritten beheben können

HPLIP

Create MS SQL Server 2008 SQL Dump

From Moritz Kobel

Created 22.10.2013

Last updated 01.11.2022

In Software

As a Linux using PostgreSQL and MySQL admin I am used to console tools. Therefore creating a sql dump (schema+data) from a MS SQL 2008 database is a challenging task.

MS SQL 2008

Sympa with Virtual Hosts using Exim

From Moritz Kobel

Created 05.07.2013

Last updated 01.11.2022

In Software

Setting up sympa with virtual hosts in an environment using exim requires some small modifications:

Apache Debian Exim Sympa

BFH VPN + Dateizugriff mit Arch Linux

From Moritz Kobel

Created 10.10.2012

Last updated 10.10.2012

In Software

Wenn man nicht mit Windows, sondern gar mit etwas speziellen wie Arch Linux auf das Netzwerk der Berner Fachhochschule zugreiffen möchte, dann kann findet man leider auf anhieb keine Anleitung im Sharepoint. Daher habe ich mal einige Eckdaten zusammengestellt.

Arch Linux BFH Gnome 3 Netzwerk

Arduino and Arch Linux

From Moritz Kobel

Created 01.10.2012

Last updated 01.10.2012

In Software

I could not use the Arduino IDE (from AUR) with its default config on Arch Linux.

Arch Linux Arduino

Fix redmine CSRF / Post-Request issue

From Moritz Kobel

Created 03.08.2012

Last updated 01.11.2022

In Software

I use the squeeze-backport of redmine on Debian.

With the default setup, all the Ajax-Post-Requests cause the logout of the current user due to the missing X-CSRF-Token.

Because I could not find a complete solution, I backported the CSRF-Code from a newer relase.

Debian Redmine Ruby on Rails Web

LXC mit Debian Squeeze

From Moritz Kobel

Created 25.07.2012

Last updated 25.07.2012

In Software

Da die aktuellen Anleitungen für LXC mit Debian Squeeze etwas spärlich und teilweise veraltet sind, notiere ich hier einige Schritte für ein aktuelles Setup.

Debian Kernel LXC

Systemstart wartet bei "Removing Leftover Files"

From Moritz Kobel

Created 02.05.2012

Last updated 02.05.2012

In Software

Nach einem Systemupdate blieb meine Workstation mit LDAP Authentifizierung beim Starten immer bei "Removing Leftover Files" stehen.

Arch Linux LDAP

Javascript Map sortieren

From Moritz Kobel

Created 02.02.2012

Last updated 02.02.2012

In Software

Die folgende Map möchte ich nach pos0 und pos1 sortieren....

var imap = {
    1: {
        name: 'Test 3',
        pos0: 30,
        pos1: 20
    },
    2: {
        name: 'Test 1',
        pos0: 10,
        pos1: 30
    },
    3: {
        name: 'Test 2',
        pos0: 20,
        pos1: 10
    }
}

Javascript

Von GPX zu FoxtrottGPS POI

From Moritz Kobel

Created 21.07.2011

Last updated 21.07.2011

In Software

Für unsere Norwegenferien wollte ich das Tomtom-OV2 über das GPX-Format in die POI-Datenbank von FoxtrottGPS (Fork von TangoGPS) importieren.

FoxtrottGPS Freerunner Python SHR

SparkleShare auf Ubuntu 11.04

From Moritz Kobel

Created 30.05.2011

Last updated 30.05.2011

In Software

Auf der Suche nach einer Dropbox Alternative, wo man einen eigenen Server verwenden kann, bin ich auf SparkleShare gestossen.

SparkleShare Ubuntu

Problem mit unvollständigen Objekten

From Moritz Kobel

Created 18.04.2011

Last updated 18.04.2011

In Software

Im Blog verursachte der folgende Code beim generieren der Tag-Seiten Probleme:

${Article.withCriteria{ tags{like('id',tagInstance.id)  } }}

Die hier geladenen Artikel-Objekte hatten bei der anschliessenden Anzeite nur einen Tag, den von der Tag-Seite.

Blog Grails

CSS Selektoren

From Moritz Kobel

Created 14.04.2011

Last updated 14.04.2011

In Software

Mit Selektoren lässt sich mehr machen, das man denkt...

CSS Web

Firecookie

From Moritz Kobel

Created 14.04.2011

Last updated 14.04.2011

In Software

Das Firefox-Add-on Firebug ist wohl den meisten Web-Entwicklern bekannt, das Firebug-Addon-on Firecookie aber wohl nicht...

Debug Web

TinyMCE und Modal Dialog

From Moritz Kobel

Created 11.04.2011

Last updated 11.04.2011

In Software

Wenn man die Pluginliste selber zusammenstellt und den Compressor verwendet, kann es sein, dass der Konfigurationsparameter "dialog_type : 'modal'" nicht korrekt arbeitet....

Javascript TinyMCE

Grails Blog Software

From Moritz Kobel

Created 29.03.2011

Last updated 29.03.2011

In Software

Um Grails besser kennen zu lernen und um dem Tandemblog eine optimierte Blogsoftware zu bieten, habe ich mich entschlossen ein neues Projekt zu starten....

Blog Grails

Sort 'mappedBy'

From Moritz Kobel

Created 29.03.2011

Last updated 01.11.2022

In Software

Sorting in Grails is easy, but defining the sort order of 'hasMany' children of an object is not obvious...

Grails

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