Why does python main.py fail with MinIO initialization error while running in VSCode works fine?

Question

I'm encountering a strange issue where my Python application runs successfully in VSCode but fails when executed directly via the terminal using the command:

python main.py

The error seems to be related to the MinIO client initialization, which is initialized at the top of the file like this:

minio_client = connect_minio.MinioClient()

However, no exception is thrown in VSCode, and everything works as expected.

Here are some key points about my setup and observations:

I'm using .env files to load environment variables via python-dotenv.

The path to .env is resolved dynamically based on the script location:

from logisticsVerification import start
env_path = Path(__file__).resolve().parent / ".env"
load_dotenv(dotenv_path=env_path)

the start.py

minioclient = MinioClient(bucket_name=bucket_name)

When running from the terminal, it appears that the .env file is not loaded correctly, leading to missing environment variables needed by [MinioClient].
In contrast, VSCode debugging mode runs without any issues, suggesting that there might be differences in:
- Working directory
- Python interpreter used
- Environment variable loading behavior

I have already checked:

The output of os.getcwd() and sys.path inside both environments.
That the .env file exists and contains all required keys.
That the same Python interpreter is used (via which python).

Yet I’m still unable to pinpoint why the module initialization behaves differently.

Code Snippet:

from imageProcess import connect_minio
env_path = Path(__file__).resolve().parent / ".env"
load_dotenv(dotenv_path=env_path)

minio_client = connect_minio.MinioClient()  # Fails here when run from terminal

What I Want to Know:

Why would the same script behave differently when run in VSCode vs terminal? What are the common reasons behind such discrepancies (e.g., working directory, environment variables, sys.path, or PYTHONPATH) — and how can I make the terminal execution consistent with VSCode’s behavior?

Any help or suggestions for further debugging would be greatly appreciated.

I change my

from logisticsVerification import start

below the

load_dotenv(dotenv_path=env_path)

everything will be ok. but I don't know why vscode can run before.

did you check if these environment variables are in .env? Maybe VSCode adds these variables? — furas
– furas, Commented Jul 11 at 1:59
if you get error message then you should show full error/traceback in question (not in comments) — furas
– furas, Commented Jul 11 at 2:00

Hoang Vinh · Accepted Answer · 2025-07-11 03:39:45Z

0

The line from logisticsVerification import start executes immediately, and if start.py or any of its imports require environment variables, they will fail because the .env file hasn't been loaded yet.

This works in VSCode because VSCode's debugger loads .env files automatically before launching your script (if configured to do so), while running from the terminal does not.

VSCode often does this under the hood:

Reads .env files (if you set it in your launch.json config or via the Python extension settings).  

Sets those environment variables into the shell/session.  

Launches your script with those env vars already available.

So even if you haven't called load_dotenv(), the environment variables are already present when start is imported.

But in your terminal, this doesn’t happen unless you call load_dotenv() before any code that uses env vars.a

answered Jul 11 at 3:39

Hoang Vinh

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2 Comments

user26558855 Jul 12 at 10:12

yes,that's th reason! I find it. thank u

Hoang Vinh Jul 15 at 4:20

I'm glad we can share knowledge together.

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