Log integer in beanshell and get integer from variables


log.info() returns the following error in JMeter beanshell:

 Error in method invocation: Method info( int ) not found in class'org.apache.logging.slf4j.Log4jLogger'


The error message indicates you are trying to pass an integer in the log.info() method. To prevent this issue, convert the integer to the type String using:

String SomeString = Integer.toString(somInteger);

Similarly, numerals are passed as strings in JMeter variables, to make arithmetic operation on them, you’ll need to convert them to integer using:

int someInteger = Integer.parseInt(someString);

yarn : ERROR: There are no scenarios; must have at least one. On Ubuntu

Issue: The following error is displayed when running yarn in the same directory as the package.jsnon file:

00h00m00s 0/0: : ERROR: There are no scenarios; must have at least one.


this is the wrong yarn, ubuntu install cmdtest.


sudo apt remove cmdtest
curl -sS https://dl.yarnpkg.com/debian/pubkey.gpg | sudo apt-key add - echo "deb https://dl.yarnpkg.com/debian/ stable main" | sudo tee /etc/apt/sources.list.d/yarn.list 
sudo apt update 
sudo apt install yarn

How to solve merge conflict in git cli?

$  git merge TEST_2
 Auto-merging test.txt
 CONFLICT (content): Merge conflict in test.txt
 Automatic merge failed; fix conflicts and then commit the result.
$git mergetool --tool-help
'git mergetool --tool=' may be set to one of the following:
$ git mergetool --tool=vimdiff

Docker cheatsheet

Create a DockerFile

At the root of your project, create a file name DockerFile, without any file extension. 

In workdir you put the absolute path to your app.

FROM node:12-alpine
COPY . .
RUN yarn install --production
CMD ["node", "/app/src/index.js"]

Build an image

Cd in the directory where your DockerFile is and run:

$sudo docker build -t getting-started .

Don’t forget the “.”  at the end of the command!

getting-started is the name of the app you are creating in docker. It will be the name of the image.

Run the image in a container

$sudo docker run -dp 3000:3000 getting-started

-p 3000:3000 is mapping the internal port 3000 (the 2nd one) to the external port 3000(the first one). So you will be able to access your app on localhost:3000.

Update an image

First you need to remove the container. For that you will need the container id:

you can get it in two different ways:

$sudo docker ps


$sudo docker container ls

that gives you the container process id. You can then stop the container:

$sudo docker stop 123456789

and then remove the container:

$sudo docker rm 123456789

You can also do that in one line by using the force option to close and remove the container in one go:

$sudo docker rm -f 123456789 

Sharing docker image:

You’ll need a docker account in hub.docker.com. 

Create a repository.

Once the repository is created, you’ll see a Docker command example to push your project in the repo:

$docker push username/getting-started:tagname


Persistency between restarts

To have data persitency between restart, you will need to mount a volume in the container. That volume will be available from the host but also from container that has mounted the same volume.

Create a volume

$sudo docker volume create todo-db

Mount the volume to the container

$sudo docker run -dp 3000:3000 -v todo-db:/etc/todos getting-started

Now your data will persist between session.

Where the data are actually stored on the disk?


$sudo docker volume inspect todo-db

It will return:



        “CreatedAt”: “2019-09-26T02:18:36Z”,

        “Driver”: “local”,

        “Labels”: {},

        “Mountpoint”: “/var/lib/docker/volumes/todo-db/_data”,

        “Name”: “todo-db”,

        “Options”: {},

        “Scope”: “local”



The mountpoint is the actual location of the data on the host.

Watch changes on a simple refresh rather than rebuilding the app:

use bind mount. 

Example command:

$docker run -dp 3000:3000 \
    -w /app -v ${PWD}:/app \
    node:12-alpine \
    sh -c "yarn install && yarn run dev"

You can check the logs: 

$docker logs -f <container-id>

Run MySql on a separate container

Why not put it in the same container as your app? It’s because you  might not want to ship your development db with your app. You might also want to scale the front-end and the back-end up differently.

1- create a network:

$sudo docker network create todo-app
$docker run -d \
   --network todo-app --network-alias mysql \
    -v todo-mysql-data:/var/lib/mysql \
    -e MYSQL_ROOT_PASSWORD=secret \
    -e MYSQL_DATABASE=todos \


You’ll notice we’re using a volume named todo-mysql-data here and mounting it at /var/lib/mysql, which is where MySQL stores its data. However, we never ran a docker volume create command. Docker recognizes we want to use a named volume and creates one automatically for us.

3- confirm the database is up and running:

docker exec -it <mysql-container-id> mysql -p

Sometimes it’s useful to start with a clean slate and remove all Docker containers and even images. Here are some handy shortcuts.

List all containers (only IDs)

$docker ps -aq

Stop all running containers

$docker stop $(docker ps -aq)

Remove all containers

$docker rm $(docker ps -aq)

Remove all images

$docker rmi $(docker images -q)

Dockerize a node app


Run command in the container

Use the command 

docker exec -it <container name> /bin/bash 

to get a bash shell in the container.

Common issues:

Error: “ENOSPC: no space left on device, open ‘/app/yarn-error.log'”

Solution: https://docs.docker.com/engine/reference/commandline/system_prune/

docker system prune

will remove networks and containers which are not in use.

docker system prune --all

will remove all network, containers and images.

What is argument[0] used for in Selenium code?


argument[0] is used in javascript function to pass on the value of the WebElement.


WebElement webElement = driver.findElement(By.xpath("xpath_element"));
JavascriptExecutor javaScriptExecutor = (JavascriptExecutor)driver;
javaScriptExecutor.executeScript("arguments[0].click()", webElement);

What is the @ sign in java used for?

The @ symbol denotes a Java Annotation. What a Java annotation does, is that it adds a special attribute to the variable, method, class, interface, or other language elements.

“In the Java computer programming language, an annotation is a form of syntactic metadata that can be added to Java source code. “