Rerun existing completed Job kubectl replace deletes the old job, if there is any error, your job definition is lost, don’t forget to save it first! Replace an existing Job with itself kubectl get job JOBNAME -o yaml | kubectl replace --force -f - Sometimes there are errors importing the job template due to auto-generated labels or selectors .. a quick and dirty hack is to filter them out using jq ...

These are not only linux snippets but also bash snippets and snippets using tools that run under Linux, *nix or sometimes even MacOSX, I should reorder this article someday ;) Settings for more reliable bash scripts set -euo pipefail this gives us …​ -e: exit script if a single command fails -u: exit script if an unset variable is used -o pipefail: return value of a pipeline is the status of the last command to exit with a non-zero status, or zero if no command exited with a non-zero status ...

Precondition: Postgres Schema exists Using this precondition should run a migration only if the schema my_schema exists. <preConditions onFail="CONTINUE"> <sqlCheck expectedResult="1"> SELECT COUNT(1) FROM information_schema.schemata WHERE schema_name = 'my_schema'; </sqlCheck> </preConditions> Resources: https://docs.liquibase.com/concepts/changelogs/preconditions.html

Permanently add SSH Key Password to the Keychain ssh-add --apple-use-keychain ~/.ssh/THEPRIVATEKEY Tool for Window Management Install rectangle Install with brew brew install rectangle Useful Shortcuts Move current app to previous or next display Ctrl+Opt+Cmd+LEFT or Ctrl+Opt+Cmd+RIGHT Maximize window Ctrl+Opt+ENTER Beginners List of Shortcuts coming from Linux …​ Finder Show hidden files in Finder: cmd + shift + . Open Finder: Option + Cmd + Space Open Location: Shift + Cmd + G Change to parent dir in Finder: super + UP ...

Extract Coordinates from the POM Helpful for build and integration environments, pipelines etc. Exctract the Project version from the pom.xml mvn org.apache.maven.plugins:maven-help-plugin:3.1.0:evaluate -Dexpression=project.version -q -DforceStdout Override a Property via local configuration e.g. to override the property xxx from your project’s pom.xml Create a directory .mvn in your project directory root Create a file named maven.config in this directory Insert -Dxxx=newvalue into the file to override this property Don’t forget to add .mvn to your .gitignore! ...

Data Normalizing Formula newVal = (oldVal-min) / (max-min) Ugly Scala Example package com.hascode import scala.collection.mutable.LinkedList object NormalizerExample extends App { val dataSet = LinkedList(1., 6.5, 3., 6.2, 20., 31.2, 50.2, 12., 0.24, 1.224, 2.2, 3.) for ((num, index) <- dataSet.zipWithIndex) { dataSet(index) = (num - dataSet.min) / (dataSet.max - dataSet.min) } println("Normalized: " + dataSet) } Normalized: LinkedList(0.01521216973578863, 0.12921819759798853, 0.05947594797769014, 0.12324029048767723, 0.3982240175619966, 0.6213992163469515, 1.0, 1.0, 0.07531115879828326, 0.40498283261802576, 0.7319742489270387, 1.0)

Use List of Parameters in Annotation-based Query Possible using MyBatis Dynamic SQL feature package com.hascode.example.mybatis; import org.apache.ibatis.annotations.Mapper; import org.apache.ibatis.annotations.Param; import org.apache.ibatis.annotations.Select; import java.util.List; @Mapper public interface SampleMapper { @Select({"<script>", "SELECT sample.bar", "FROM sampletable sample", "WHERE sample.id IN", "<foreach item='item' index='index' collection='ids'", "open='(' separator=',' close=')'>", "#{item}", "</foreach>", "</script>"}) List<Foo> getSamplesMatchingIds(@Param("ids") List<String> ids); } The mapper may now be used with a list of parameter objects: var samples = sampleMapper.getSamplesMatchingIds(List.of("24059e5b-aa07-424d-855e-50f499b8f697", "65140fc0-fc9f-42d2-9531-5e5d6caeba30")); Call a Procedure package com.hascode.example.mybatis; import org.apache.ibatis.annotations.Mapper; import org.apache.ibatis.annotations.Options; import org.apache.ibatis.annotations.Select; import org.apache.ibatis.mapping.StatementType; @Mapper public interface SampleMapper { @Select("CALL SCHEMA.CL.setScope(#{scope})") @Options(statementType = StatementType.CALLABLE) void setScope(int scope); } ...

Aggregate existing Labels MATCH (n) RETURN DISTINCT labels(n) Or unwinding label pairs MATCH (n) WITH DISTINCT labels(n) AS labels UNWIND labels AS label RETURN DISTINCT label ORDER BY label

Observability Strategies USE USE stands for: Utilization - Percent time the resource is busy, such as node CPU usage Saturation - Amount of work a resource has to do, often queue length or node load Errors - Count of error events This method is best for hardware resources in infrastructure, such as CPU, memory, and network devices. For more information, refer to The USE Method. Source: https://grafana.com/docs/grafana/latest/dashboards/build-dashboards/best-practices/ RED RED stands for: Rate - Requests per second Errors - Number of requests that are failing Duration - Amount of time these requests take, distribution of latency measurements This method is most applicable to services, especially a microservices environment. For each of your services, instrument the code to expose these metrics for each component. RED dashboards are good for alerting and SLAs. A well-designed RED dashboard is a proxy for user experience. ...

WordPress anonymize IP in comments Add as last line in theme’s functions.php: function wpb_remove_commentsip($comment_author_ip) { return '127.0.0.1'; } add_filter('pre_comment_user_ip','wpb_remove_commentsip'); WordPress remove version info Add as last line in theme’s functions.php: function remove_version_info() { return ''; } add_filter('the_generator', 'remove_version_info'); List of all WordPress Hooks