Environment variables

The binary reads its configuration from the environment; your application's own settings are read as in Python (os.environ, pydantic-settings). It does not read .env files (pydantic-settings reads environment variables only, see Models): export the variables, as an orchestrator does, or set -a; . ./.env; set +a locally.

These variables and their defaults are a stable interface (Versioning and deprecation).

The binary

Variable	Default	Effect
DATABASE_URL	postgresql://postgres@127.0.0.1/postgres	also the database of <binary> migrate; SQLAlchemy-style URLs accepted (postgresql+psycopg://, postgresql+asyncpg://): the driver named there decides details that differ between drivers (SQL databases)
DB_POOL_SIZE	32	connections in the pool (the binary's own pool replaces the engine's)
HOST, PORT	0.0.0.0, 8080	listening address when the binary is run without command-line options (with options: uvicorn's, see Logging)
UVICORN_*, FORWARDED_ALLOW_IPS		uvicorn's options as variables (UVICORN_PORT, UVICORN_LOG_LEVEL, UVICORN_ACCESS_LOG...), as uvicorn reads them
PY2AXUM_SOURCE_ROOT	the project's directory at translation	the directory the records' pathname and the tracebacks' file paths start with (Logging)
PY2AXUM_PYTHON_URL	unset	the Python process serving python-side paths (Hybrid mode); unset: they answer 404
PY2AXUM_LOG_LEVEL	unset	uvicorn's --log-level (kept for older deployments); the application's own records follow its logging configuration, as in Python
PY2AXUM_SHUTDOWN_TIMEOUT	25	seconds to wait for in-flight requests and streams after SIGTERM (Graceful shutdown)
PY2AXUM_SQL_DEBUG	unset	set: a database error is logged with its SQL statement (not its bound values)
PY2AXUM_MAX_BODY	unset	largest request body in bytes, 413 past it (Security § Request input); unset: no limit, like uvicorn
PY2AXUM_STACK_SIZE	268435456 (256 MiB)	stack of the runtime threads, in bytes (reserved address space; Security § Request input)
PY2AXUM_DB_TIMEZONE	discovered	the session TimeZone psycopg would get (sqlx forces UTC at connect, the runtime restores the server's); set it to skip the discovery
PY2AXUM_PYTHON_VERSION	the patch recorded at generation	the patch release of CPython whose messages to reproduce where they changed inside a minor (e.g. 3.13.5; see Python versions); generation records the one of --python or .python-version, else the transpiler's when it runs the project's minor, else the newest
PY2AXUM_STREAM_CHUNK	65536	block size (bytes) of large list responses streamed from the session
PY2AXUM_STREAM_MIN_ROWS	1000	a literal LIMIT at or below it keeps a list response buffered (Large list responses)
SENTRY_DSN, SENTRY_ENVIRONMENT, SENTRY_RELEASE		read as the Python SDK reads them (Sentry)
PROMETHEUS_MULTIPROC_DIR		prometheus_client's multiprocess mode, with the same files as CPython (Prometheus metrics)
PROMETHEUS_DISABLE_CREATED_SERIES		as in prometheus_client (Prometheus metrics)

The recorder (Python side)

On the Python side, py2axum.record (an ASGI wrapper that records anonymized traffic for replay, run as uvicorn py2axum.record:app) is configured by these variables: see Conformance and replay § Replay.

Variable	Default	Effect
PY2AXUM_RECORD	unset	the JSONL file to write; unset, the application is served untouched
PY2AXUM_RECORD_APP	(required)	the application to wrap, as module:attribute (api.main:app)
PY2AXUM_RECORD_KEY	random per process	secret of the pseudonyms (HMAC): set it to the same value in every worker so that one e-mail gets one pseudonym
PY2AXUM_RECORD_FIELDS	none	extra JSON/form/query keys to mask, comma separated (first_name,iban,phone)
PY2AXUM_RECORD_HEADERS	none	extra request headers to keep (x-tenant); x-* and a few standard ones are kept
PY2AXUM_RECORD_SKIP	^/(health\|metrics\|docs\|openapi.json)	regex of paths not recorded
PY2AXUM_RECORD_MAX_BODY	1 MiB	bodies above this size (bytes) are not recorded
PY2AXUM_RECORD_RAW	unset	1 keeps multipart and binary bodies as they are (base64): not anonymized, tests only