Episode 11: Inspecting Image, Copying files into and from Docker

In this article, we will learn the way we can :

1. Inspecting Image.
2. Copy docker data into and from the container

1. Inspecting Image:

→ We may need more information on our dockerized project to store in the database (say node version, created date, docker exposed PORT)

STEP 1: We need to get an image ID whose data we need. We use the below command

docker ps -a
docker image

STEP 2: Paste the image ID in the below command

docker image inspect <docker-image-id>
eg. docker image e6bed6a65a54

2. Copying Docker Files:

→ It is possible we can copy files from codebase to docker container and vice-versa.

→ Let us a file in our project to copy (say test/test-file-1.js)

a. Copying from Project to specific docker container

→ For this we need a docker container, we use the below command to create contained:

docker build .         // Create Docker Image (copy image id)
docker run -p 3000:80 <image-ID> // Create Docker Container
docker ps -a             // Copy recently created container id   

→ We use the below command to paste it into the docker command

docker cp <source_file> <container-id-or-name>:/<directory-to-paste>
// copy specific file inside a directory
eg1 docker cp test/test_file_1.js optimistic_wozniak:/test

// copy all files inside a directory
eg2 docker cp test/. optimistic_wozniak:/test

TRICK:

It is possible to check into a container

For this, we go to the docker section  → expand our container

b. Copying from a specific docker container to Project

→ Also sometimes it happens containers is shared by our colleague or clients

→ We might need it in our project.

→ We now have the test file in our container, let us delete the project’s test files

→ The below command will help us copy from docker’s container to our project directory.

docker cp <container-id-or-name>:/<directory-to-copy> <source_file>
eg. docker cp optimistic_wozniak:/test test

a. Before running the command:

b. After running the command:

When do we require this 🤔 ?

Eg. When we run the application from docker, reading the docker file in the container will be difficult. We can copy into our project and read from our favourite editor.

Video:

Closing Thoughts:

In this article, we have understood ways to get detailed information about docker images, copy files into and from the docker container.

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