Generate random values in Postman to use in your tests

When you want your tests to be able to run whenever you want, you should use values which are random.

In Postman, click on the name of Collection and then open the ‘Pre-request Script’ tab.

There, add the following:

// get a random number between a minimum and a maximum
// gives you current datetime with milliseconds like 2022810_171012_174
postman.setGlobalVariable("getCurrentDate",  () => {
  const date=new Date(); 
  return String(date.getFullYear())  
      + String(date.getMonth()+1) 
      + String(date.getDate()) 
      + '_' 
      + String(date.getHours() < 10 ? "0"+date.getHours() : date.getHours()) 
      + String(date.getMinutes() < 10 ? "0"+date.getMinutes() : date.getMinutes()) 
      + String(date.getSeconds() < 10 ? "0" + date.getSeconds() : date.getSeconds())
      + '_' 
      + String(date.getMilliseconds())
})

You can now use this function in your tests. This enables you to make your strings (like emailaddresses) random by adding the current datetime to it.

To use it, open your test, click on the ‘Pre-request Script’ tab and add the following.

var currentDate = eval(pm.globals.get("getCurrentDate"))();
var randomEmail = `postman-${currentDate}@pauledenburg.com`;
pm.environment.set("randomEmail", randomEmail);

You can now use the generated value in the body of your POST-request by referencing it as {{randomEmail}}

Autoprefixer: The color-adjust shorthand is currently deprecated

The full warning is:

Warning
(2728:3) autoprefixer: Replace color-adjust to print-color-adjust. The color-adjust shorthand is currently deprecated.

The easy fix:

rename color-adjust to print-color-adjust

This didn’t work for me as the issue is in the node_modules directory.

Other fix: add the following to your package.json:

  "resolutions": {
    "autoprefixer": "10.4.5"
  },

Then run the following again: yarn install

Check if a variable is set in Selenium IDE and set it when it’s not declared yet

Sometimes you want to use child/parent like tests.

This enables you to treat the ‘child test’ more like a template which you can re-use. But you might want to influence the variable used in this templated test.

To test whether a variable was set and set it when it was not, you’d do the following.

Testing whether a variable was set is done with this javascript string:

"${randomResellerEmail}" == "$" + "{randomResellerEmail}"

In Selenium IDE this looks like the following.

Test for a variable and set it when it did not exist

Store current datetime in variable in Selenium IDE and use it for a random email address

I use variables all the time. And to be able to re-use a test over and over again, I need random email addresses whenever I fill in forms.

For this I define a variable with the current date and time and then a variable which will hold the email address which uses the current date and time.

My random email address will look like: selenium-20220318_122803@pauledenburg.com

Just store the following as 1 string into the ‘Target’ part of your command.

const date=new Date(); return String(date.getFullYear())  + String(date.getMonth()+1) + String(date.getDate()) + '_' + String(date.getHours() < 10 ? "0"+date.getHours() : date.getHours()) + String(date.getMinutes() < 10 ? "0"+date.getMinutes() : date.getMinutes()) + String(date.getSeconds() < 10 ? "0" + date.getSeconds() : date.getSeconds())

It will look like this in Selenium IDE:

storing the current datetime in a variable in Selenium IDE

Add bearer authentication to your Swagger endpoint

In your .json definition file:

{
  "swagger": "2.0".
  ...
  "securityDefinitions": {
    "bearerAuth": {
      "type": "apiKey",
      "in": "header",
      "name": "Authorization",
    }
  },
  ...
  "paths": {
    "get": {
      "/path": {
        "security": [
          {"bearerAuth": []}
        ],
        ...
      }
    }
  }

official documentation is here: https://swagger.io/docs/specification/authentication/bearer-authentication/

Git remove local branches that don’t exist remote

The quick way:

git branch --merged master | grep -v '^[ *]*master$' | xargs git branch -d
git remote prune origin

Use the following to have the branches displayed before you’re asked to delete them.

branches=$(git branch --merged master | grep -v '^[ *]*master$'); \
printf '\n\nBranches to be removed:\n---\n'; \
echo ${branches} | xargs -n1; \
printf '---\n\nRemove the branches above? [Ny] ' \
    &&  read shouldDelete \
    && [[ "${shouldDelete}" =~ [yY] ]] \
      && echo $branches | xargs git branch -d \
      || echo 'aborted' 

source: https://stackoverflow.com/a/16906759

Process ‘wanwakuang` with high process load

I noticed today that my server was very slow. Looking at the running processes, I noted that process wanwakuang and 000000 were going crazy.

process wanwakuang caused the load to go very high

Searching wanwakuang on Google did not yield much results, but this article on HackerNews was very helpful: https://translate.google.com/translate?sl=auto&tl=en&u=http://hackernews.cc/archives/34789

Appearently wanwakuang is a mining process.

However, I could not find the binary on my system. My server is only running Docker containers, so probably one of the containers was at fault.

To find the docker container with the exploit, I executed the command:

$ find /var/lib/docker -type f -name wanwakuang
/var/lib/docker/overlay2/1752e86653539d82b50cf24c3d3f69b203fe059ca1650447016ca69033d468bf/diff/root/.configrc/a/wanwakuang
/var/lib/docker/overlay2/1752e86653539d82b50cf24c3d3f69b203fe059ca1650447016ca69033d468bf/diff/tmp/.W10-unix/.rsync/a/wanwakuang
/var/lib/docker/overlay2/1752e86653539d82b50cf24c3d3f69b203fe059ca1650447016ca69033d468bf/merged/root/.configrc/a/wanwakuang
/var/lib/docker/overlay2/1752e86653539d82b50cf24c3d3f69b203fe059ca1650447016ca69033d468bf/merged/tmp/.W10-unix/.rsync/a/wanwakuang

To find out which Docker container was attached to this overlay, I issued this command I found on stackoverflow:

$ docker inspect $(docker ps -qa) \
  | jq -r 'map([.Name, .GraphDriver.Data.MergedDir]) \
  | .[] | "(.[0])\t(.[1])"' \
  | grep '1752e86653539d82b50cf24c3d3f69b203fe059ca1650447016ca69033d468bf'

Knowing the name I could terminate the container. It was being used for SSH and could be removed.

Debugging cron on Docker

I had the issue of cronjobs not working (correctly) on my Docker instances.

This is what I did to fix it:

  1. Set correct permissions: chmod 0600 /etc/cron.d/cronjob
  2. Set correct owner: chown root /etc/cron.d/cronjob

When it failed, I could not find the logs of why it failed.
In order to see the output of the failed cronjobs, I installed postfix (because the output of cronjobs is being mailed) and I installed rsyslog

  1. Install postfix:
    apt-get update; apt-get install -y postfix; mkfifo /var/spool/postfix/public/pickup; service postfix restart
  2. Install rsyslog:
    apt-get update; apt-get install -y rsyslog; rsyslogd &

Now, whenever a cronjob failed, I could find output in either two locations:

  1. In the syslog: /var/log/syslog
  2. In the mail sent to root: /var/mail/root
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