Log on Micha Kops' Tech Notes

Logback and Spring Boot - Change Log Level to custom format

Thu, 19 Aug 2021 00:00:00 +0200

Create a custom converter

This class converts the well known log levels to a custom format

CustomLogLevelConverter.java

package com.hascode;

public class CustomLogLevelConverter extends ClassicConverter {
    @Override
    public String convert(ILoggingEvent event) {
        switch (event.getLevel().toInt()) {
            case Level.ERROR_INT:
                return "ERROR!!!";
            case Level.WARN_INT:
                return "WARN!!";
            case Level.INFO_INT:
                return "INFO!";
            case Level.TRACE_INT:
                return "DEBUG";
            default:
                return event.getLevel().toString();
        }
    }
}

Register the converter

The following Logback config includes some defaults and registers our custom converter.

Sensor Fun: Location Based Services and GPS for Android

Sun, 30 May 2010 00:00:00 +0200

The Android SDK offers a nice API to receive information about available providers for location based services and get the current location and coordinates.

In this short tutorial we’re going to build a small activity that displays a list of available location providers and shows the current position using GPS services.

Example Application

Create a new Android Project using ADT and your IDE with a package named com.hascode.android.location_app

Add the permissions needed to the AndroidManifest.xml – it should look like this

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
	package="com.hascode.android.location_app" android:versionCode="1"
	android:versionName="1.0">
	<application android:icon="@drawable/icon" android:label="@string/app_name">
		<activity android:name=".LocationActivity" android:label="@string/app_name">
			<intent-filter>
				<action android:name="android.intent.action.MAIN" />
				<category android:name="android.intent.category.LAUNCHER" />
			</intent-filter>
		</activity>

	</application>
	<uses-sdk android:minSdkVersion="7" />

	<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"></uses-permission>
	<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"></uses-permission>
	<uses-permission android:name="android.permission.ACCESS_LOCATION_EXTRA_COMMANDS"></uses-permission>
	<uses-permission android:name="android.permission.ACCESS_MOCK_LOCATION"></uses-permission>
</manifest>

Git Snippets

Mon, 01 Mar 2010 00:00:00 +0100

Show commits from another branch not contained in current branch

git cherry -v otherbranch
+ f7d6a569bb6912aac97fce9ac92c4302863fb0d9 thecommit

Find deleted files

git log --diff-filter=D --summary

Create empty commit

sometimes necessary for build/deploy pipelines …

git commit --allow-empty -m "Empty-Commit"

Cherry pick without commit

git cherry-pick -n HASH

Using vimdiff for diff

set it via git config

git config --global diff.tool vimdiff
git config --global merge.tool vimdiff

set it via ~/.gitconfig

[diff]
    tool = vimdiff
[merge]
    tool = vimdiff

Java Snippets

Mon, 01 Mar 2010 00:00:00 +0100

Remote Debug a Pod’s Java Process

Simple steps for remote debugging a Java process running on a k8 pod:

Edit deployment and add the following parameters to the Java start line: -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=127.0.0.1:5005

Also add the following port mapping at the section container → ports in the deployment:
```
- containerPort: 5005
  protocol: TCP
```
Safe, wait for the new pods and then add a port forward for port 5005 for this pod:
```
kubectl port-forward podname 5005
```

Spring Boot Snippets

Mon, 01 Mar 2010 00:00:00 +0100

Define and Configure Log Groups

This allows to configure a group of loggers at the same time

Define a log group named myaspect with two packages
application.properties
```
logging.group.myaspect=com.hascode.package1,com.hascode.package2
```
Configure the log group and set all loggers to level TRACE
application.properties
```
logging.level.myaspect=TRACE
```

This is also possible as parameter on startup

java -Dlogging.level.myaspect=TRACE myapp.jar

Use JUnit 5 with Spring Boot

Use newer versions of Surefire and Failsafe plugins:

<properties>
[..]
  <maven-failsafe-plugin.version>2.22.0</maven-failsafe-plugin.version>
  <maven-surefire-plugin.version>2.22.0</maven-surefire-plugin.version>
</properties>