101 lines
2.3 KiB
Markdown
101 lines
2.3 KiB
Markdown
# FastAPI – Environment Setup
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This document describes the initial setup required to prepare a Python environment for developing a FastAPI application.
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The steps below ensure isolation, dependency management, and reproducibility across environments.
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---
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## Prerequisites
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Before starting, ensure the following are installed on your system:
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* Python 3.8 or higher
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* `pip` (Python package manager)
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* `venv` module (included by default with most Python installations)
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You can verify your Python version with:
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```bash
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python3 --version
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```
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---
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## Step 1: Create a Virtual Environment
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A virtual environment isolates project dependencies and prevents conflicts with system-wide Python packages.
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From the project root directory, run:
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```bash
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python3 -m venv .venv
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```
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This command creates a `.venv` directory containing the isolated Python environment.
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---
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## Step 2: Activate the Virtual Environment
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Activate the virtual environment before installing any dependencies.
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### Linux / macOS
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```bash
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source .venv/bin/activate
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```
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### Windows (PowerShell)
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```powershell
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.venv\Scripts\Activate.ps1
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```
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After activation, your shell prompt should indicate that the virtual environment is active.
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---
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## Step 3: Install FastAPI
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With the virtual environment activated, install FastAPI using `pip`:
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```bash
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pip install fastapi
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```
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This installs the FastAPI framework and its required dependencies.
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> Note: In a real application, FastAPI is commonly used with an ASGI server such as `uvicorn`, which can be installed later if needed.
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---
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## Step 4: Freeze Dependencies
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To ensure reproducibility across environments (local, CI/CD, staging, production), export the installed dependencies to a requirements file:
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```bash
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pip freeze > requirement.txt
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```
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This file should be committed to version control and used by deployment pipelines to install exact dependency versions.
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---
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## Resulting Files
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After completing the steps above, your project directory should include:
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* `.venv/` – Python virtual environment (should not be committed to VCS)
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* `requirement.txt` – Dependency lock file
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---
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## Best Practices
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* Always activate the virtual environment before working on the project
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* Do not commit `.venv/` to source control
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* Keep `requirement.txt` updated when adding or upgrading dependencies
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* Use the same `requirement.txt` in CI/CD pipelines for consistent builds
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---
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