sentry-python Instrument FastAPI app with Sentry and OTel and check differences.

Instrument a Django application once with Sentry and once with Sentry using OpenTelementry for span creation. We want to compare the span waterfalls, to see the differences and what needs to be done to have feature parity.

Test setup:

Application: https://github.com/getsentry/demo-movie-search/tree/main/backend/fastapi A request to the /api/shows/{pk}/ API endpoint will do:

Run a FastAPI view with a custom middleware
Runs a database query
In the middleware a Redis counter is increased
Start a FastAPI background task

Scenario 1) Sentry:

sentry_sdk.init(
    dsn=sentry_dsn,
    release=sentry_release,
    environment=sentry_environment,
    traces_sample_rate=sentry_traces_sample_rate,
    send_default_pii=sentry_default_pii,
    debug=sentry_debug,
)

This will load Sentries integrations (like FastAPI, Starlette, ...) by default and those Sentry integrations will create spans. Opentelementry is not used.

Scenario 2) Sentry using OpenTelementry:

sentry_sdk.init(
    dsn=sentry_dsn,
    release=sentry_release,
    environment=sentry_environment,
    traces_sample_rate=sentry_traces_sample_rate,
    send_default_pii=sentry_default_pii,
    debug=sentry_debug,
    _experiments={
        "otel_powered_performance": True
    },
)

This will disable all Sentry span creation and spans will only be created by the OpenTelemetry SDK.

Jun 28 '24 06:06 antonpirker

Example traces for both scenarios:

Sentry: https://sentry-sdks.sentry.io/performance/trace/468c8e612cf04fff85a6d7a08643dac9/?node=ag-bee52f45864e1065&node=txn-d1a91910d62640f3af1a7f9098bf42f7&project=6618415&query=http.method%3AGET&referrer=performance-transaction-summary&showTransactions=recent&source=performance_transaction_summary&statsPeriod=1h&timestamp=1719555666&transaction=%2Fapi%2Fshows%2F%7Bshow_id%7D&unselectedSeries=p100%28%29&unselectedSeries=avg%28%29
Sentry using OTel: https://sentry-sdks.sentry.io/performance/trace/a159065d04eeb490536d391007264ed1/?node=txn-b691b33f2c0e45c686331b138915ed0b&project=6618415&query=http.method%3AGET&referrer=performance-transaction-summary&showTransactions=recent&source=performance_transaction_summary&statsPeriod=1h&timestamp=1719555842&transaction=%2Fapi%2Fshows%2F%7Bshow_id%7D&unselectedSeries=p100%28%29&unselectedSeries=avg%28%29

Jun 28 '24 06:06 antonpirker