# Environment Configuration Guide
This guide provides detailed information about gNMIBuddy's environment variable management system, including advanced configuration options and best practices.
## Overview
gNMIBuddy uses **Pydantic Settings** for centralized, type-safe environment variable management. The system supports multiple configuration sources with a clear precedence hierarchy.
## Environment Variable Precedence
gNMIBuddy follows a strict precedence order when loading configuration:
1. **CLI arguments** (highest priority)
```bash
gnmibuddy --log-level debug --inventory custom.json device list
```
2. **Operating system environment variables**
```bash
export GNMIBUDDY_LOG_LEVEL=debug
export NETWORK_INVENTORY=custom.json
gnmibuddy device list
```
3. **`.env` file values**
```bash
# .env file
GNMIBUDDY_LOG_LEVEL=debug
NETWORK_INVENTORY=custom.json
```
4. **Default values** (lowest priority)
## .env File Configuration
### Default Behavior
- gNMIBuddy automatically looks for a `.env` file in the project root
- Missing `.env` files are handled gracefully (no errors)
- Malformed `.env` files are handled gracefully with warnings
### Custom .env Files
Use the `--env-file` option to specify custom environment files:
```bash
# Development environment
gnmibuddy --env-file .env.development device list
# Production environment
gnmibuddy --env-file .env.production device list
# Testing environment
gnmibuddy --env-file tests/.env device list
```
### Environment File Examples
#### Basic Configuration
```bash
# .env
NETWORK_INVENTORY=inventory/devices.json
GNMIBUDDY_LOG_LEVEL=info
```
#### Development Configuration
```bash
# .env.development
NETWORK_INVENTORY=dev_inventory.json
GNMIBUDDY_LOG_LEVEL=debug
GNMIBUDDY_STRUCTURED_LOGGING=true
GNMIBUDDY_EXTERNAL_SUPPRESSION_MODE=development
GNMIBUDDY_MCP_TOOL_DEBUG=true
```
#### Production Configuration
```bash
# .env.production
NETWORK_INVENTORY=/opt/gnmibuddy/inventory.json
GNMIBUDDY_LOG_LEVEL=warning
GNMIBUDDY_STRUCTURED_LOGGING=true
GNMIBUDDY_LOG_FILE=/var/log/gnmibuddy/gnmibuddy.log
GNMIBUDDY_EXTERNAL_SUPPRESSION_MODE=cli
```
## Supported Environment Variables
### Network Configuration
| Variable | Description | Type | Default | Example |
| ------------------- | ---------------------------------- | ----- | ------- | ------------------------- |
| `NETWORK_INVENTORY` | Path to device inventory JSON file | `str` | `None` | `/path/to/inventory.json` |
### Logging Configuration
| Variable | Description | Type | Default | Example |
| ------------------------------------- | -------------------------------- | ------ | ---------- | ------------------------------------- |
| `GNMIBUDDY_LOG_LEVEL` | Global logging level | `str` | `info` | `debug`, `info`, `warning`, `error` |
| `GNMIBUDDY_MODULE_LEVELS` | Module-specific log levels | `str` | `None` | `src.cmd=warning,src.inventory=debug` |
| `GNMIBUDDY_LOG_FILE` | Custom log file path | `str` | Sequential | `/custom/path/gnmibuddy.log` |
| `GNMIBUDDY_STRUCTURED_LOGGING` | Enable JSON logging format | `bool` | `false` | `true`, `false` |
| `GNMIBUDDY_EXTERNAL_SUPPRESSION_MODE` | External library log suppression | `str` | `cli` | `cli`, `mcp`, `development` |
### MCP Configuration
| Variable | Description | Type | Default | Example |
| -------------------------- | ------------------------- | ------ | ------- | --------------- |
| `GNMIBUDDY_MCP_TOOL_DEBUG` | Enable MCP tool debugging | `bool` | `false` | `true`, `false` |
