Test As A Config (TAAC) — a configuration-driven network test automation framework. TAAC provides a declarative approach to FBOSS network device testing, where test scenarios are expressed as structured configurations rather than imperative scripts.

A test is a TestConfig containing one or more playbooks; a playbook runs against a DUT (device under test) and is composed of ordered stages; each stage is a list of steps — the smallest units of work (e.g. RUN_SSH_COMMAND_STEP, DUMMY_STEP, plus device-management ones). Stages express ordering and parallelism; playbooks group what runs against which device.

Smoke-tested via facebook/fboss's public Docker images on CentOS Stream 9. Docker is the only host-side dependency.

# Build the vendor-shippable TAAC image (auto-builds base image if missing)
./docker/build-taac-image.sh

That single command builds the FBOSS CentOS base image if missing, compiles the full dep tree (folly, fizz, wangle, mvfst, fbthrift), builds TAAC, and produces fboss-taac — a self-contained image with all transitive deps baked in.

The image's entrypoint sets PYTHONPATH and LD_LIBRARY_PATH automatically, so vendors can docker run --rm fboss-taac python3 ... with no host-side state. See docker/README.md for the build-flow diagram and layer-cache contract.

For iterative work on TAAC source or thrift schemas in a bind-mounted workspace — no image rebuild required — see the in-container iteration section in docker/README.md (Python source edits work via PYTHONPATH; thrift edits use the baked-in taac-regen-thrift helper).

First build takes ~22 min cold (mostly the deps compile). Docker's layer cache makes subsequent rebuilds after TAAC-only source changes finish in ~30 sec. See docker/README.md for the layer cache contract and when to rebuild what.

Inside the fboss-taac image, generated thrift bindings + the TAAC Python source land under:

/scratch/installed/taac-<HASH>/lib/python3/site-packages/

They contain taac/, ixia/, neteng/, facebook/, fb303/. Each generated thrift_types.py ships a co-located types.py / ttypes.py / clients.py shim so legacy-style imports resolve.

The <HASH> suffix is getdeps' per-configuration cache key — it changes if you pass different --extra-cmake-defines to getdeps.py build.

The image's entrypoint automatically sets PYTHONPATH and LD_LIBRARY_PATH, so imports work out of the box:

docker run --rm fboss-taac python3 -c '
    from neteng.fboss.ctrl.thrift_types import NdpEntryThrift
    from taac.test_as_a_config.thrift_types import TestConfig
    print("ok")
'

TAAC's Python modules (e.g. taac.libs.taac_runner) include Meta-internal imports that aren't shipped in this slice. Set TAAC_OSS=1 so the imports take their OSS branch:

export TAAC_OSS=1
python3 -c 'import taac.libs.taac_runner; print("ok")'

Some runtime functionality is stubbed in OSS mode (NDS drainer, COOP patcher, ValidationStep, AristaSSHHelper, etc.) and will raise NotImplementedError if invoked on a code path that requires it. Imports succeed; trying to actually use those features fails.

import asyncio
from taac.test_as_a_config.thrift_types import (
    TestConfig, Playbook, Stage, Step, StepName, Endpoint, DeviceOsType,
)
from taac.libs.taac_runner import TaacRunner

cfg = TestConfig(
    name='smoke',
    basset_pool='',  # Meta-internal hardware reservation pool; '' is fine for OSS
    playbooks=[Playbook(
        name='dummy_playbook',
        stages=[Stage(steps=[Step(name=StepName.DUMMY_STEP)])],
    )],
    endpoints=[Endpoint(name='your-host', dut=True)],
    host_os_type_map={'your-host': DeviceOsType.FBOSS},
    startup_checks=[],
)

# skip_post_setup_wait skips a 180s interface-stabilization sleep
# that's only useful when booting real hardware.
async def main():
    runner = TaacRunner(test_config=cfg, skip_post_setup_wait=True)
    await runner.async_test_setUp()
    await runner.run_tests()

asyncio.run(main())

examples/smoke_live_device.py runs the same shape against real device(s), driving both a DUMMY_STEP playbook and a RUN_SSH_COMMAND_STEP playbook. It expects TAAC_OSS=1, TAAC_SSH_USER, and TAAC_SSH_PASSWORD to be set on the host — run_taac_docker.sh auto-forwards any TAAC_* env var into the container, so keep secrets out of inline bash -c strings (e.g. source them from a gitignored file or a vault):

# Source the password from a file (chmod 600), not the command line.
export TAAC_OSS=1 TAAC_SSH_USER=netops
source ~/.taac-secrets  # exports TAAC_SSH_PASSWORD=...

./docker/run_taac_docker.sh run \
    python3 /workspace/examples/smoke_live_device.py \
        --device-info-csv /workspace/examples/topology/sample_device_info.csv \
        --circuit-info-csv /workspace/examples/topology/sample_circuit_info.csv \
        --command "uname -a"

The wrapper bind-mounts the repo at /workspace, sets PYTHONPATH to include it, and runs --network host so internal-DNS hostnames resolve inside the container.

Without --hosts, every hostname listed in --device-info-csv is used as a DUT. Pass --hosts host1 host2 to run against a subset. examples/topology/ ships sample CSVs as templates — copy them, replace the placeholder hostnames / OS column with your own fleet, and point --device-info-csv / --circuit-info-csv at your copies.

DEVICE_OS_DRIVER_CLASS_MAP ships with FbossSwitch registered for DeviceOsType.FBOSS. For other OS types (Arista, Cisco, etc.), register your own AbstractSwitch subclass:

from taac.utils.driver_factory import register_driver_class
from taac.test_as_a_config.thrift_types import DeviceOsType
from my_pkg.my_driver import MyArista  # your subclass of AbstractSwitch

register_driver_class(DeviceOsType.ARISTA_OS, MyArista)

This project is licensed under the Apache License 2.0 — see the LICENSE file for details.