plain.connect

Connect your Plain app to Plain Cloud via OTLP export.

• Overview
• Settings
• Sampling
• What gets exported
• Pageview tracking
• Support forms
• Toolbar
• FAQs
• Installation

Overview

You can use plain.connect to export traces, metrics, and logs from your Plain app to Plain Cloud. The framework already instruments itself with OpenTelemetry spans and histograms — plain.connect activates them by providing the OTLP exporters and bridges Python's logging module into OTLP log records.

Set one environment variable and your app starts pushing telemetry:

PLAIN_CONNECT_EXPORT_TOKEN=your-token

If CONNECT_EXPORT_TOKEN is not set, the package is a no-op — safe to install without configuration.

Settings

All settings can be set via PLAIN_-prefixed environment variables or in app/settings.py.

Sampling

By default, all traces are exported. To reduce volume, set a sample rate:

CONNECT_TRACE_SAMPLE_RATE = 0.1  # Export 10% of traces

Metrics are not affected by sampling — histograms aggregate in-process and export periodically regardless of the trace sample rate.

What gets exported

Traces — HTTP request spans and database query spans instrumented by the framework.

Metrics — OTel histograms like db.client.query.duration, aggregated and pushed every 60 seconds.

Logs — Records from the plain and app loggers, plus anything propagating to the root logger, are bridged into OTLP log records and exported with trace_id / span_id set from the active span. The minimum severity is controlled by CONNECT_LOG_LEVEL (default INFO); the root logger's level is widened to that floor when needed so libraries using getLogger(__name__) reach the exporter. To prevent feedback loops, two sources are skipped on the export path: the opentelemetry namespace, and any record emitted from inside the OTLP exporter's background thread (e.g. urllib3 connection errors raised by the exporter's own HTTP call). Your application's urllib3 logs are exported normally.

Pageview tracking

plain.connect can track page views in your app — anonymous page-view analytics plus, optionally, attribution to your signed-in users. This is independent of the OTLP export above.

Add the tag to your base template, just before </body>:

{% connect_pageviews %}

Then set the public endpoint token:

PLAIN_CONNECT_PAGEVIEWS_TOKEN=plain_pv_...

The tag renders nothing until the token is set. Once enabled, it reports the URL, title, referrer, and a first-party anonymous id on each page load and SPA navigation (History pushState / back-forward).

If your app sends a Content-Security-Policy, add the pageview ingest host to connect-src — the script beacons to CONNECT_PAGEVIEWS_URL (https://beacon.plainframework.com by default). Without it, the browser blocks every pageview beacon.

User attribution

To attribute pageviews to your signed-in users, also set the shared secret:

PLAIN_CONNECT_SECRET_KEY=...

When set, the tag encrypts the signed-in user's id (AES-256-GCM) into an opaque token that only Plain Cloud can decrypt — the raw id never appears in your HTML. The user is read from plain.auth; apps without it (or anonymous visitors) are still counted, their pageviews simply carry no user id.

The same CONNECT_SECRET_KEY is used by the {% connect_support_fields %} widget below — one secret per app.

Support forms

plain.connect ships a tag for sending contact-form submissions to a support endpoint on Plain Cloud. You create the endpoint in the App's Support settings (it gives you an id like plain_sf_abc123), then drop a normal HTML form into your template:

<meta name="referrer" content="strict-origin-when-cross-origin">
<form action="{{ connect_support_url('plain_sf_abc123') }}" method="POST">
  {% connect_support_fields %}
  <input name="name" placeholder="Your name">
  <input name="email" type="email" placeholder="Email">
  <textarea name="message" required></textarea>
  <button type="submit">Send</button>
</form>

The {% connect_support_fields %} tag injects three hidden inputs:

• plain_connect_render_token — HMAC-signed timestamp; rejected if it's too fresh (bots that submit instantly) or too stale (rendered hours ago)
• plain_connect_identity — encrypted user id when plain.auth is installed and the visitor is signed in
• plain_connect_check — honeypot field; submissions that fill it are silently discarded

Both anti-spam signals require CONNECT_SECRET_KEY. Without it the inputs still render (as empty values), so the form remains submittable — you just lose render-token verification and identity attribution.

Cross-origin Origin header

The form posts cross-origin to Plain Cloud, so the browser's Origin header serialization is governed by the page's Referrer-Policy. Plain ships Referrer-Policy: same-origin by default, which causes Chrome and Firefox to send Origin: null on no-cors cross-origin POSTs — and Plain Cloud rejects submissions with a null origin.

The <meta name="referrer"> tag in the example above overrides the document's policy to strict-origin-when-cross-origin, so the browser sends Origin: https://yourapp.com and the submission goes through. Putting it in <head> is preferable when you can — it applies before any subresources load — but inline next to the form still works for the form submission. Your app's global Referrer-Policy header is unaffected.

Field names

A few field names are reserved — the platform reads them directly:

Any other field name is captured into the conversation's extras JSON dict automatically — no extra configuration needed.

JSON vs form-action

The endpoint accepts either application/x-www-form-urlencoded (the standard <form action="..."> path) or application/json (for fetch-driven submissions). The field names are the same in both shapes. On the form-action path _next redirects the browser on success; on the JSON path the response is {"ok": true, "conversation": "<uuid>"}.

Toolbar

If you have plain.toolbar installed, plain.connect adds a Trace button that links the current request straight to its trace in Plain Cloud.

The button only appears when export is active (CONNECT_EXPORT_TOKEN is set), so it stays out of the way in local dev. It links to a short /t/<trace_id> URL on CONNECT_CLOUD_URL, which resolves the trace to its app and redirects you to the full trace view — no app slug needed in the link.

If a request wasn't sampled for export (see Sampling), the button shows "Not sampled" instead. Because traces export in a background batch, a freshly-clicked link may briefly land on a "locating trace" page that retries until the trace arrives.

FAQs

What happens if the export endpoint is unreachable?

The OTLP exporters batch and retry automatically. If the endpoint is down, telemetry is dropped after retries — it does not block your application.

Does this add latency to requests?

No. Trace spans are exported in a background thread via BatchSpanProcessor. Metrics are flushed periodically by a background thread. Neither blocks request handling.

Installation

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