Documentation has inadequate information about use of the systemd facts

[Routhinator]

I cannot get the systemd facts to work.

The docs seem to indicate that kwargs need to be passed, however any attempt to pass kwargs throws an error:

code:

"""
Node Preflight checks
"""

from pyinfra.api import host
from pyinfra.facts.systemd import SystemdStatus

if host.get_fact(SystemdStatus, services=["kubelet"]).kubelet.service:
    print("This system has a running kubelet, and the deployment actions are intended"\
        "solely for new or reset nodes. Please use the upgrade actions for existing nodes.")
    exit(1)

-> % pyinfra inventories/red-squadron.py deploy_node.py --limit green03                                       (⎈|kubernetes-admin@red-squadron:N/A) 
--> Loading config...
--> Loading inventory...
--> Connecting to hosts...
    [green03]      Connected

--> Preparing operation files...
    Loading: deploy_node.py

--> Disconnecting from hosts...
--> An exception occurred in: deploy_node.py:

Traceback (most recent call last):
  File "/home/routhinator/.local/share/uv/tools/pyinfra/lib/python3.14/site-packages/pyinfra_cli/util.py", line 65, in exec_file
    exec(PYTHON_CODES[filename], data)
    ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "deploy_node.py", line 15, in <module>
    local.include(
    ~~~~~~~~~~~~~^
        filename=path.join("tasks", "node_deploy_preflight.py"),
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/home/routhinator/.local/share/uv/tools/pyinfra/lib/python3.14/site-packages/pyinfra/local.py", line 38, in include
    exec_file(filename)
    ~~~~~~~~~^^^^^^^^^^
  File "/home/routhinator/.local/share/uv/tools/pyinfra/lib/python3.14/site-packages/pyinfra_cli/util.py", line 71, in exec_file
    raise UnexpectedExternalError(e, filename)
Traceback (most recent call last):
  File "/home/routhinator/.local/share/uv/tools/pyinfra/lib/python3.14/site-packages/pyinfra_cli/util.py", line 65, in exec_file
    exec(PYTHON_CODES[filename], data)
    ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/routhinator/projects/routh-forgejo/routh-ca/pyinfra/kubernetes_cluster/tasks/node_deploy_preflight.py", line 8, in <module>
    if host.get_fact(SystemdStatus, services=["kubelet"]).kubelet.service:
       ~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: get_fact() got an unexpected keyword argument 'services'

During handling of the above exception, another exception occurred:

pyinfra_cli.exceptions.UnexpectedExternalError: <exception str() failed>

And without kwargs.. trying to use these facts results in:

code:

"""
Node Preflight checks
"""

from pyinfra.api import host
from pyinfra.facts.systemd import SystemdStatus

if host.get_fact(SystemdStatus).kubelet.service:
    print("This system has a running kubelet, and the deployment actions are intended"\
        "solely for new or reset nodes. Please use the upgrade actions for existing nodes.")
    exit(1)

output:

-> % pyinfra inventories/red-squadron.py deploy_node.py --limit green03                                       (⎈|kubernetes-admin@red-squadron:N/A) 
--> Loading config...
--> Loading inventory...
--> Connecting to hosts...
    [green03]      Connected

--> Preparing operation files...
    Loading: deploy_node.py

--> Disconnecting from hosts...
--> An exception occurred in: deploy_node.py:

Traceback (most recent call last):
  File "/home/routhinator/.local/share/uv/tools/pyinfra/lib/python3.14/site-packages/pyinfra_cli/util.py", line 65, in exec_file
    exec(PYTHON_CODES[filename], data)
    ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "deploy_node.py", line 15, in <module>
    local.include(
    ~~~~~~~~~~~~~^
        filename=path.join("tasks", "node_deploy_preflight.py"),
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/home/routhinator/.local/share/uv/tools/pyinfra/lib/python3.14/site-packages/pyinfra/local.py", line 38, in include
    exec_file(filename)
    ~~~~~~~~~^^^^^^^^^^
  File "/home/routhinator/.local/share/uv/tools/pyinfra/lib/python3.14/site-packages/pyinfra_cli/util.py", line 71, in exec_file
    raise UnexpectedExternalError(e, filename)
Traceback (most recent call last):
  File "/home/routhinator/.local/share/uv/tools/pyinfra/lib/python3.14/site-packages/pyinfra_cli/util.py", line 65, in exec_file
    exec(PYTHON_CODES[filename], data)
    ~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/routhinator/projects/routh-forgejo/routh-ca/pyinfra/kubernetes_cluster/tasks/node_deploy_preflight.py", line 8, in <module>
    if host.get_fact(SystemdStatus).kubelet.service:
       ~~~~~~~~~~~~~^^^^^^^^^^^^^^^
TypeError: get_fact() missing 2 required positional arguments: 'host' and 'cls'

During handling of the above exception, another exception occurred:

pyinfra_cli.exceptions.UnexpectedExternalError: <exception str() failed>

[EricDriussi]

Hi there! I think you might be importing the wrong host! Try from pyinfra import host instead (no api).

Also to be clear (and I might not understand what data point you want here), using the services argument you'll get the first matching item.
So for example, on my system I have both 'syslog.service': False and 'syslog.socket': False, but running

print(host.get_fact(SystemdStatus, services=["syslog"]))

only returns

{'syslog.service': False}

To get the socket I need to run

print(host.get_fact(SystemdStatus, services=["syslog.socket"]))

Looking at the resulting dict I'm not sure how your .kubelet.service is supposed to behave (I'm no python expert so take this with a grain of salt), but if I want to get the bool out of it I need to run

print(host.get_fact(SystemdStatus, services=["syslog.socket"])["syslog.socket"])

A bit clunky tbh but seems to work 🤷