Overview

This project contains a few Shell scripts supporting the execution of tasks both from within Kubernetes (k8s) pods (i.e., from within a container) and from a laptop or a virtual machine (VM). The idea is to use the same support scripts to test an application both from the usual daily environment (e.g., laptop, virtual machine (VM) on a cloud provider) and from a container in a Kubernertes deployment.

K8S Job Wrappers is abbreviated as KJB.

Usage

• Download and extract the archive of Shell scripts (from a Dockerfile, just remove the sudo keyword):

LOGSUP_VERSION="0.0.7"
curl -L -s \
  https://github.com/cloud-helpers/k8s-job-wrappers/archive/refs/tags/v$LOGSUP_VERSION.tar.gz \
  -o k8s-job-wrappers.tar.gz && \
tar zxf k8s-job-wrappers.tar.gz && rm -f k8s-job-wrappers.tar.gz && \
sudo mv -f k8s-job-wrappers-$LOGSUP_VERSION /usr/local/ && \
sudo rm -f /usr/local/k8s-job-wrappers && \
sudo ln -s /usr/local/k8s-job-wrappers-$LOGSUP_VERSION /usr/local/k8s-job-wrappers

• All the following steps may be performed from your own Shell script

• Specify a few environment variables

  • URL of the caller script:

export KJW_SCRIPT_URL="https://github.com/cloud-helpers/k8s-job-wrappers/tree/master/k8s-job-wrapper-main.sh"

• File-path to the log file:

export KJW_LOG_FILE="$HOME/tmp/application/my-application.log"

• Name of the caller function:

export KJW_FUNC="main"

• URL of a container image specification file (e.g., Dockerfile, if any):

export KJW_CTR_FILE="URL-to-container-image-specification-file"

• URL of the Kubernetes deployment file (if any):

export KJW_K8S_DEPL_FILE="URL-to-K8S-deployment-YAML-file"

• Make sure that the log file is writeable:

mkdir -p $(dirname $KJW_LOG_FILE)
rm -f $KJW_LOG_FILE ; touch $KJW_LOG_FILE

• Source the Shell support script:

source /usr/local/k8s-job-wrappers/setLogFunc.sh

• Call the log functions
  • Beginning of the script:

logStart "My own application - We can achieve great things with collaboration"

• Single-line log:

log "A single line log"

• Multi-line log:

logMulti "The first line of a multi-line log" \
         ". Another line" \
         ". Last line"

• End of the script:

logEnd "My own application - We can achieve great things with collaboration"

• And that is it. In order to check the resulting log file:

cat $KJW_LOG_FILE

• Clean up the generated log file:

rm -f $KJW_LOG_FILE