azure-appconfiguration-py

# Azure App Configuration SDK for Python

Centralized configuration management with feature flags and dynamic settings.

## Installation

```bash
pip install azure-appconfiguration
```

## Environment Variables

```bash
AZURE_APPCONFIGURATION_CONNECTION_STRING=Endpoint=https://<name>.azconfig.io;Id=...;Secret=...
# Or for Entra ID:
AZURE_APPCONFIGURATION_ENDPOINT=https://<name>.azconfig.io
```

## Authentication

### Connection String

```python
from azure.appconfiguration import AzureAppConfigurationClient

client = AzureAppConfigurationClient.from_connection_string(
    os.environ["AZURE_APPCONFIGURATION_CONNECTION_STRING"]
)
```

### Entra ID

```python
from azure.appconfiguration import AzureAppConfigurationClient
from azure.identity import DefaultAzureCredential

client = AzureAppConfigurationClient(
    base_url=os.environ["AZURE_APPCONFIGURATION_ENDPOINT"],
    credential=DefaultAzureCredential()
)
```

## Configuration Settings

### Get Setting

```python
setting = client.get_configuration_setting(key="app:settings:message")
print(f"{setting.key} = {setting.value}")
```

### Get with Label

```python
# Labels allow environment-specific values
setting = client.get_configuration_setting(
    key="app:settings:message",
    label="production"
)
```

### Set Setting

```python
from azure.appconfiguration import ConfigurationSetting

setting = ConfigurationSetting(
    key="app:settings:message",
    value="Hello, World!",
    label="development",
    content_type="text/plain",
    tags={"environment": "dev"}
)

client.set_configuration_setting(setting)
```

### Delete Setting

```python
client.delete_configuration_setting(
    key="app:settings:message",
    label="development"
)
```

## List Settings

### All Settings

```python
settings = client.list_configuration_settings()
for setting in settings:
    print(f"{setting.key} [{setting.label}] = {setting.value}")
```

### Filter by Key Prefix

```python
settings = client.list_configuration_settings(
    key_filter="app:settings:*"
)
```

### Filter by Label

```python
settings = client.list_configuration_settings(
    label_filter="production"
)
```

## Feature Flags

### Set Feature Flag

```python
from azure.appconfiguration import ConfigurationSetting
import json

feature_flag = ConfigurationSetting(
    key=".appconfig.featureflag/beta-feature",
    value=json.dumps({
        "id": "beta-feature",
        "enabled": True,
        "conditions": {
            "client_filters": []
        }
    }),
    content_type="application/vnd.microsoft.appconfig.ff+json;charset=utf-8"
)

client.set_configuration_setting(feature_flag)
```

### Get Feature Flag

```python
setting = client.get_configuration_setting(
    key=".appconfig.featureflag/beta-feature"
)
flag_data = json.loads(setting.value)
print(f"Feature enabled: {flag_data['enabled']}")
```

### List Feature Flags

```python
flags = client.list_configuration_settings(
    key_filter=".appconfig.featureflag/*"
)
for flag in flags:
    data = json.loads(flag.value)
    print(f"{data['id']}: {'enabled' if data['enabled'] else 'disabled'}")
```

## Read-Only Settings

```python
# Make setting read-only
client.set_read_only(
    configuration_setting=setting,
    read_only=True
)

# Remove read-only
client.set_read_only(
    configuration_setting=setting,
    read_only=False
)
```

## Snapshots

### Create Snapshot

```python
from azure.appconfiguration import ConfigurationSnapshot, ConfigurationSettingFilter

snapshot = ConfigurationSnapshot(
    name="v1-snapshot",
    filters=[
        ConfigurationSettingFilter(key="app:*", label="production")
    ]
)

created = client.begin_create_snapshot(
    name="v1-snapshot",
    snapshot=snapshot
).result()
```

### List Snapshot Settings

```python
settings = client.list_configuration_settings(
    snapshot_name="v1-snapshot"
)
```

## Async Client

```python
from azure.appconfiguration.aio import AzureAppConfigurationClient
from azure.identity.aio import DefaultAzureCredential

async def main():
    credential = DefaultAzureCredential()
    client = AzureAppConfigurationClient(
        base_url=endpoint,
        credential=credential
    )
    
    setting = await client.get_configuration_setting(key="app:message")
    print(setting.value)
    
    await client.close()
    await credential.close()
```

## Client Operations

| Operation | Description |
|-----------|-------------|
| `get_configuration_setting` | Get single setting |
| `set_configuration_setting` | Create or update setting |
| `delete_configuration_setting` | Delete setting |
| `list_configuration_settings` | List with filters |
| `set_read_only` | Lock/unlock setting |
| `begin_create_snapshot` | Create point-in-time snapshot |
| `list_snapshots` | List all snapshots |

## Best Practices

1. **Use labels** for environment separation (dev, staging, prod)
2. **Use key prefixes** for logical grouping (app:database:*, app:cache:*)
3. **Make production settings read-only** to prevent accidental changes
4. **Create snapshots** before deployments for rollback capability
5. **Use Entra ID** instead of connection strings in production
6. **Refresh settings periodically** in long-running applications
7. **Use feature flags** for gradual rollouts and A/B testing