Python/Docker : FileNotFoundError: [Errno 2] No such file or directory:

Question

I am using a Python code to open a text file and write some information and close it. When I run this code on Jupyter notebook it runs perfectly but when I run this as a part of Docker container it gives the following error.

Current directory is C:/app where I have stored Dockerfile, testfile.txt and Hello1.py. In addition I have gone to Virtual Machine and have added C: as shared folder.

Python File

  file = open("C:/Python/testfile.txt","w")
  file.write("Hello World")
  file.write("This is our new text file")
  file.close()

Docker File

 FROM python:latest
 WORKDIR /data
 COPY testfile.txt /data
 COPY Hello1.py /data
 CMD ["python","Hello1.py"]

Error Recieved

 $ docker run sid1980
 Traceback (most recent call last):
 File "Hello1.py", line 7, in <module>
 file = open("C:/Python/testfile.txt","w")
 FileNotFoundError: [Errno 2] No such file or directory: 'C:/Python/testfile.txt'

Answer 1

Your python program cannot access C:/ of the host machine. You need to change the file path to reference the testfile.txt that exists within the container .

file = open("/data/testfile.txt","w")

Also note that this will not modify the testfile.txt that exists on the host. It will write to the file that is inside the container.