plain.observer 0.19.1

On-page telemetry and observability tools for Plain.

plain.observer

On-page telemetry and observability tools for Plain.

• Installation
• Content Security Policy (CSP)

Installation

Install the plain.observer package from PyPI:

uv add plain.observer

Add plain.observer to your INSTALLED_PACKAGES:

# app/settings.py
INSTALLED_PACKAGES = [
    # ...
    "plain.observer",
]

Include the observer URLs in your URL configuration:

# app/urls.py
from plain.observer.urls import ObserverRouter
from plain.urls import Router, include

class AppRouter(Router):
    namespace = ""
    urls = [
        # ...
        include("observer/", ObserverRouter),
    ]

Run migrations to create the necessary database tables:

plain migrate

After installation, Observer will automatically integrate with your application's toolbar (if using plain.admin). You can access the web interface at /observer/traces/ or use the CLI commands to analyze traces.

Content Security Policy (CSP)

If you're using a Content Security Policy (CSP), the Observer toolbar panel requires frame-ancestors 'self' to display trace information in an iframe.

Without this directive, the toolbar panel will fail to load with a CSP error: "Refused to frame... because an ancestor violates the following Content Security Policy directive: 'frame-ancestors 'none'".

Example CSP configuration:

DEFAULT_RESPONSE_HEADERS = {
    "Content-Security-Policy": (
        "default-src 'self'; "
        "script-src 'self' 'nonce-{request.csp_nonce}'; "
        "style-src 'self' 'nonce-{request.csp_nonce}'; "
        "frame-ancestors 'self'; "  # Required for Observer toolbar
        # ... other directives
    ),
}