Resolve Python .env inconsistencies: load dotenv before imports to prevent MinIO client failures in terminal

Learn why Python apps work in VSCode but fail in the terminal: load .env before imports. Use load_dotenv first to fix MinIO client initialization reliably.

Python projects that rely on environment variables often behave perfectly under VSCode’s debugger yet fall apart when launched from the terminal. If your MinIO client is initialized at module import time and your .env is not loaded early enough, that mismatch becomes visible immediately: VSCode preloads your .env, the terminal does not. The result is a confusing split-brain where the same code seems stable in one place and fragile in another.

Reproducing the issue

The root of the problem is import order. If a module import triggers code that needs environment variables, but loading of .env happens later, terminal runs will fail because those variables are missing at the moment they’re first read.

# main.py (problematic)
from shipCheck import boot  # importing this triggers code that needs env vars
from pathlib import Path
from dotenv import load_dotenv
env_file = Path(__file__).resolve().parent / ".env"
load_dotenv(dotenv_path=env_file)

Inside the imported module a MinIO client is instantiated at the top level. That work happens as soon as the import is executed, not when you later call functions.

# shipCheck/boot.py (runs on import)
from dataBridge import objstore
client_handle = objstore.StorageClient()  # touches env during import time

This is enough to break terminal execution if the MinIO client needs keys from the environment and the .env file hasn’t been loaded yet.

Why this happens

In Python, importing a module executes its top-level code immediately. If that code reaches out for configuration via environment variables and those variables are not yet present, you’ll get failures that look like missing configuration or failing initializers. In VSCode, the debugger can preload environment variables from a .env file before your script even starts, provided you have configured it that way. That means that by the time your module is imported, the environment is already populated. In a plain terminal run, no such preload occurs automatically, so the order of operations becomes critical.

This explains why you observed that moving the import below the dotenv loader made everything work. The moment you ensure .env is loaded first, the MinIO client initialization that follows during import finds the values it needs.

The fix

Make sure you load .env before any import or code path that requires environment variables. In other words, do not import modules that initialize the MinIO client (or anything else that reads env vars) until after you’ve called load_dotenv.

# main.py (fixed)
from pathlib import Path
from dotenv import load_dotenv
cfg_path = Path(__file__).resolve().parent / ".env"
load_dotenv(dotenv_path=cfg_path)
from shipCheck import boot  # safe now: env vars are already loaded

If you initialize the client directly in the same file, the same principle applies. Ensure loading the .env happens first, then construct the client. Names here are illustrative; the behavior is what matters.

# storage_app.py (correct order)
from pathlib import Path
from dotenv import load_dotenv
from imgOps import storage_bind
conf_file = Path(__file__).resolve().parent / ".env"
load_dotenv(dotenv_path=conf_file)
minio_session = storage_bind.StorageClient()

Why this is important

Keeping environment loading deterministic avoids hard-to-track discrepancies between IDE-driven runs and bare terminal executions. It also eliminates hidden dependencies on how tooling sets up your process. You already checked working directory, interpreter, sys.path, and the presence of the .env file itself; those can indeed differ across environments. In your case, the deciding factor was that VSCode had already injected the .env values into the process before your script ran, masking the import-order issue.

Takeaways

Load your .env as the first meaningful step of the program startup, then import modules that depend on those variables. Be aware that VSCode can preload .env for you, which makes order-of-execution bugs harder to spot until you switch to the terminal. When things diverge, capture the full traceback in the terminal, verify that the required keys are actually present in .env, and confirm whether the IDE has provided extra variables that your shell lacks. Aligning the initialization order eliminates the discrepancy and makes both execution paths consistent.