Starlette/FastAPI Support

edit

Incorporating Elastic APM into your Starlette project only requires a few easy steps.

Installation

edit

Install the Elastic APM agent using pip:

$ pip install elastic-apm

or add elastic-apm to your project’s requirements.txt file.

Setup

edit

To set up the agent, you need to initialize it with appropriate settings.

The settings are configured either via environment variables, or as initialization arguments.

You can find a list of all available settings in the Configuration page.

To initialize the agent for your application using environment variables, add the ElasticAPM middleware to your Starlette application:

from starlette.applications import Starlette
from elasticapm.contrib.starlette import ElasticAPM

app = Starlette()
app.add_middleware(ElasticAPM)

BaseHTTPMiddleware breaks contextvar propagation, as noted here. This means the ElasticAPM middleware must be above any BaseHTTPMiddleware in the final middleware list. If you’re calling add_middleware repeatedly, add the ElasticAPM middleware last. If you’re passing in a list of middleware, ElasticAPM should be first on that list.

To configure the agent using initialization arguments:

from starlette.applications import Starlette
from elasticapm.contrib.starlette import make_apm_client, ElasticAPM

apm = make_apm_client({
    'SERVICE_NAME': '<SERVICE-NAME>',
    'SECRET_TOKEN': '<SECRET-TOKEN>',
    'SERVER_URL': '<SERVER-URL>',
})
app = Starlette()
app.add_middleware(ElasticAPM, client=apm)

FastAPI

edit

Because FastAPI supports Starlette middleware, using the agent with FastAPI is almost exactly the same as with Starlette:

from fastapi import FastAPI
from elasticapm.contrib.starlette import ElasticAPM

app = FastAPI()
app.add_middleware(ElasticAPM)

Usage

edit

Once you have configured the agent, it will automatically track transactions and capture uncaught exceptions within starlette.

Capture an arbitrary exception by calling capture_exception:

try:
    1 / 0
except ZeroDivisionError:
    apm.capture_exception()

Log a generic message with capture_message:

apm.capture_message('hello, world!')

Performance metrics

edit

If you’ve followed the instructions above, the agent has installed our instrumentation middleware which will process all requests through your app. This will measure response times, as well as detailed performance data for all supported technologies.

Due to the fact that asyncio drivers are usually separate from their synchronous counterparts, specific instrumentation is needed for all drivers. The support for asynchronous drivers is currently quite limited.

Ignoring specific routes
edit

You can use the TRANSACTIONS_IGNORE_PATTERNS configuration option to ignore specific routes. The list given should be a list of regular expressions which are matched against the transaction name:

apm = make_apm_client({
    # ...
    'TRANSACTIONS_IGNORE_PATTERNS': ['^GET /secret', '/extra_secret']
    # ...
})

This would ignore any requests using the GET /secret route and any requests containing /extra_secret.

Supported Starlette and Python versions

edit

A list of supported Starlette and Python versions can be found on our Supported Technologies page.

Elastic APM only supports asyncio when using Python 3.7+