DT5215 Control SDK — Python

The control and monitoring API of the DT5215 FERS concentrator, in Python, with no dependencies: the standard library is enough.

pip install dt5215

import dt5215

with dt5215.connect("192.168.50.125", username="user", password="user") as dev:
    info = dev.info()
    print(info.hostname, info.info.sw_release)

    for chain in dev.chains.status().enabled:
        print("chain", chain.chain, chain.board_count, "boards",
              "%.1f Mbps" % chain.mbps)

    for board in dev.chains.links().boards:
        print(board.id, board.name, board.tempBoard, "C", board.hv_Vmon, "V")

Python 3.8 and later, on Linux, Windows and macOS.

What is in it

Everything the instrument's web interface can do, grouped the way the API is grouped:

Event data is not here: it leaves the instrument over the binary streaming sockets that Janus and FERSlib speak. This SDK is the control plane.

Three things worth knowing

The firmware answers HTTP 200 with result: false. A client that only reads the status code believes every refusal succeeded. This SDK checks the body and raises DeviceError with the instrument's own message — including the configuration validator's list of complaints, which is otherwise hidden behind "configuration validation failed".

Tokens expire (7 days), and restarting the bridge application throws them all away. Pass username/password and the SDK logs in when it needs to, notices a 401, logs in again and retries the request once. dev.alive() is the one operation that answers without a token: call it to tell "the instrument is down" from "my token is stale".

Some operations take minutes. chains.rescan() runs the whole enumeration and blocks until it is over. To follow it instead:

dev.chains.rescan_async()
status = dev.chains.wait_enumeration(on_progress=lambda s: print(s.progress, "%"))
print(dev.chains.enumeration_log())

The same shape works for the board firmware upgrade:

info = dev.boards.fw_upload("firmware.ffu")      # what the file holds, and for which models
dev.boards.fw_start(dev.chains.links().boards)   # Board, BoardRef, (chain, node) or "0:1"
status = dev.boards.wait_fw_upgrade(on_progress=lambda s: print(s.overall, "%"))

Errors

Six kinds, all deriving from dt5215.Dt5215Error:

try:
    dev.boards.write_register(0, 1, 0x1000, 0x42)
except dt5215.InvalidArgument as e:
    print("my mistake, in parameter", e.name)
except dt5215.DeviceError as e:
    print("the instrument said no:", e.reason)

Typed results, and the fields the SDK does not know yet

Every result is a dataclass, so the editor can complete it and mypy can check it. Every result also keeps the dictionary it came from:

info = dev.info()
info.network.ten_giga.mtu          # typed
info.raw["info"]["sysversion"]     # anything, including a field added by a newer firmware

HTTPS

The instrument serves plain HTTP today; HTTPS is coming and the SDK side is ready:

dev = dt5215.connect("https://dt5215.lan", username="user", password="user",
                     tls=dt5215.Tls(ca_file="/etc/ssl/ni-ca.pem"))

Tls carries the CA bundle, a client certificate for mutual TLS, and insecure=True for a self-signed certificate on a closed network. The default port follows the scheme and verification is on by default. No operation knows which scheme it is on, so nothing else changes the day the firmware serves TLS.

From the shell

The package installs a dt5215 command:

dt5215 --host 192.168.50.125 info
dt5215 chains
dt5215 boards
dt5215 health
dt5215 rescan --log
dt5215 watch --interval 2
dt5215 get /get_pll
dt5215 post /set_board_sync '{"master_slave": 0, "clk_source": 1}'

DT5215_HOST, DT5215_USER, DT5215_PASSWORD and DT5215_TOKEN fill in what you leave out.

Without an instrument

pip install dt5215-emulator
dt5215-emulator --port 8080
DT5215_HOST=127.0.0.1:8080 dt5215 info

The emulator answers the whole API, statefully, and reproduces the firmware's quirks on purpose. It is what this SDK's own tests run against.

Examples

examples/ has twelve, numbered in the order they are worth reading, from 01_connect_and_info.py to 12_raw_endpoint.py. They all take DT5215_HOST, DT5215_USER and DT5215_PASSWORD from the environment, and they are part of the test suite — an example that does not run is documentation that lies.

Tests

pip install -e ".[test]"
pytest

They run against the emulator, so no instrument is needed.